Merge branch 'master' into fs_svg

# Conflicts:
#	src/slic3r/GUI/Gizmos/GLGizmoEmboss.hpp

resources/icons/snap.svg

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg id="a" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16">
+  <path fill="none" stroke="#808080" stroke-linecap="round" stroke-miterlimit="10" d="m1.5,11.5V3.5c0-1.104569435119629.895430564880371-2,2-2h9c1.104569435119629,0,2,.895430564880371,2,2v8" />
+  <line x1="1.5" y1="14.5" x2="14.5" y2="14.5" style="fill:none; stroke:#ed6b21; stroke-linecap:round; stroke-miterlimit:10;"/>
+  <path d="m7,15h-3V5.237499999999272c0-.683452377914364.447715250171314-1.237499999999272,1-1.237499999999272h2v11Z" style="fill:#ed6b21; stroke-width:0px;"/>
+  <path d="m9,15h3V5.237499999999272c0-.683452377914364-.447715250171314-1.237499999999272-1-1.237499999999272h-2v11Z" style="fill:#ed6b21; stroke-width:0px;"/>
+</svg>

resources/profiles/PapapiuLab.idx

@@ -0,0 +1,2 @@
+min_slic3r_version = 2.6.0-alpha1
+0.1.0 Initial version

resources/profiles/PapapiuLab.ini

@@ -0,0 +1,505 @@
+# Print profiles for Papapiu printers.
+[vendor]
+name = Papapiu
+config_version = 0.1.0
+config_update_url = https://files.prusa3d.com/wp-content/uploads/repository/PrusaSlicer-settings-master/live/PapapiuLab/
+
+
+
+[printer_model:Papapiu_N1S]
+name = Papapiu N1S
+variants = 0.4
+technology = FFF
+bed_model = Papapiu_N1S_Bed.stl
+bed_texture = Papapiu_N1_Texture.png
+thumbnail = Papapiu_N1S_thumbnail.png
+default_materials = "Generic PLA @Papapiu"; Generic PETG HF @Papapiu; Generic PLA @Papapiu; Esun ePA-CF @Papapiu; Generic ABS @Papapiu; Generic TPU @Papapiu
+
+[print:*common*]
+compatible_printers_condition = printer_model=~/(Papapiu_N1S).*/
+allow_empty_layers = 0
+avoid_crossing_perimeters = 0
+avoid_crossing_perimeters_max_detour = 0
+bottom_fill_pattern = monotonic
+extra_perimeters = 0
+bottom_solid_layers = 8
+bottom_solid_min_thickness = 0
+bridge_acceleration = 0
+bridge_angle = 0
+bridge_speed = 60
+brim_offset = 0
+brim_width = 0
+clip_multipart_objects = 1
+complete_objects = 0
+complete_objects_one_skirt = 0
+complete_objects_sort = object
+default_acceleration = 12000
+dont_support_bridges = 1
+draft_shield = 0
+ensure_vertical_shell_thickness = 1
+exact_last_layer_height = 0
+external_perimeter_extrusion_width = 0.4
+external_perimeter_speed = 90%
+extruder_clearance_height = 25
+extruder_clearance_radius = 45
+extrusion_width = 0.4
+fill_angle = 45
+fill_density = 15%
+fill_pattern = cubic
+first_layer_acceleration = 3000
+first_layer_extrusion_width = 0.45
+first_layer_height = 0.2
+first_layer_speed = 100
+gap_fill = 1
+gap_fill_speed = 50
+gcode_comments = 0
+gcode_label_objects = 1
+infill_acceleration = 12000
+infill_anchor = 600%
+infill_anchor_max = 5
+infill_every_layers = 1
+infill_extruder = 1
+infill_extrusion_width = 0.4
+infill_first = 0
+infill_only_where_needed = 0
+infill_overlap = 18%
+infill_speed = 150
+interface_shells = 0
+ironing = 0
+ironing_flowrate = 15%
+ironing_spacing = 0.1
+ironing_speed = 15
+ironing_type = top
+layer_height = 0.15
+max_print_speed = 300
+max_volumetric_speed = 12
+min_skirt_length = 4
+notes = 
+only_retract_when_crossing_perimeters = 0
+ooze_prevention = 0
+output_filename_format = {input_filename_base}_{layer_height}mm_{filament_type[0]}_{print_time}.gcode
+perimeter_acceleration = 12000
+perimeter_extruder = 1
+perimeter_extrusion_width = 0.4
+perimeter_speed = 120
+perimeters = 2
+post_process = 
+print_settings_id = 
+raft_layers = 0
+resolution = 0
+seam_position = aligned
+skirt_distance = 10
+skirt_height = 1
+skirts = 2
+slice_closing_radius = 0.049
+small_perimeter_speed = 25
+solid_fill_pattern = rectilinear
+solid_infill_below_area = 0
+solid_infill_every_layers = 0
+solid_infill_extruder = 1
+solid_infill_extrusion_width = 0.4
+solid_infill_speed = 80%
+spiral_vase = 0
+standby_temperature_delta = -5
+support_material = 0
+support_material_angle = 0
+support_material_auto = 1
+support_material_buildplate_only = 1
+support_material_contact_distance_bottom = 0.2
+support_material_contact_distance_top = 0.2
+support_material_extruder = 0
+support_material_extrusion_width = 0.38
+support_material_interface_contact_loops = 0
+support_material_interface_extruder = 0
+support_material_interface_layers = 2
+support_material_interface_pattern = rectilinear
+support_material_interface_spacing = 0.2
+support_material_interface_speed = 100%
+support_material_pattern = rectilinear
+support_material_solid_first_layer = 0
+support_material_spacing = 2
+support_material_speed = 50
+support_material_synchronize_layers = 0
+support_material_threshold = 65
+support_material_with_sheath = 0
+support_material_xy_spacing = 60%
+thin_walls = 0
+top_fill_pattern = monotonic
+top_infill_extrusion_width = 0.4
+top_solid_infill_speed = 60%
+top_solid_layers = 8
+top_solid_min_thickness = 0
+travel_speed = 250
+travel_speed_z = 0
+wipe_tower = 0
+wipe_tower_bridging = 10
+wipe_tower_no_sparse_layers = 0
+wipe_tower_rotation_angle = 0
+wipe_tower_width = 60
+wipe_tower_x = 170
+wipe_tower_y = 140
+elefant_foot_compensation = 0.1
+
+[print:*0.15mm*]
+bottom_solid_layers = 7
+top_solid_layers = 7
+layer_height = 0.15
+bridge_flow_ratio = 0.7
+max_print_speed = 250
+solid_infill_speed = 80%
+
+[print:*0.2mm*]
+bottom_solid_layers = 5
+top_solid_layers = 5
+layer_height = 0.2
+bridge_flow_ratio = 0.8
+
+[print:0.15mm NORMAL @Papapiu]
+inherits = *common*; *0.15mm*
+max_print_speed = 300
+bottom_solid_layers = 8
+top_solid_layers = 8
+
+[print:0.15mm FAST @Papapiu]
+inherits = *common*; *0.15mm*
+compatible_printers_condition = printer_model=~/(Papapiu_N1S).*/
+external_perimeter_speed = 140
+first_layer_infill_speed = 60
+first_layer_speed = 100
+gap_fill_speed = 50
+infill_speed = 230
+ironing_speed = 15
+max_print_speed = 300
+max_volumetric_speed = 25
+perimeter_speed = 160
+small_perimeter_speed = 25
+solid_infill_speed = 80%
+top_solid_infill_speed = 60%
+fill_pattern = cubic
+
+[print:0.20mm NORMAL @Papapiu]
+inherits = *common*; *0.2mm*
+fill_pattern = cubic
+external_perimeter_speed = 120
+infill_speed = 160
+compatible_printers_condition = printer_model=~/(Papapiu_N1S).*/
+
+[print:0.20mm FAST @Papapiu]
+inherits = 0.15mm FAST @Papapiu; *0.2mm*
+compatible_printers_condition = printer_model=~/(Papapiu_N1S).*/
+external_perimeter_speed = 140
+first_layer_infill_speed = 60
+first_layer_speed = 100
+gap_fill_speed = 50
+infill_speed = 230
+ironing_speed = 15
+max_print_speed = 300
+max_volumetric_speed = 25
+perimeter_speed = 160
+small_perimeter_speed = 25
+solid_infill_speed = 80%
+top_solid_infill_speed = 60%
+
+
+# Common printer preset
+[printer:*common*]
+before_layer_gcode = ;BEFORE_LAYER_CHANGE\n;[layer_z]\nG92 E0\n;{if layer_num == 2 }SET_FILAMENT_SENSOR SENSOR=my_sensor ENABLE=1{endif}\n\n
+between_objects_gcode = 
+color_change_gcode = M600
+cooling_tube_length = 5
+cooling_tube_retraction = 91.5
+default_filament_profile = "Generic PLA @Papapiu"
+default_print_profile = "0.20mm NORMAL @Papapiu"
+deretract_speed = 40
+end_gcode = PRINT_END
+extra_loading_move = -2
+extruder_colour = ""
+gcode_flavor = marlin
+high_current_on_filament_swap = 0
+layer_gcode = ;AFTER_LAYER_CHANGE\n;[layer_z]\n
+machine_limits_usage = time_estimate_only
+machine_max_acceleration_e = 5000
+machine_max_acceleration_extruding = 9000
+machine_max_acceleration_retracting = 9000
+machine_max_acceleration_travel = 12000,12000
+machine_max_acceleration_x = 12000
+machine_max_acceleration_y = 12000
+machine_max_acceleration_z = 100
+machine_max_feedrate_e = 60
+machine_max_feedrate_x = 500
+machine_max_feedrate_y = 500
+machine_max_feedrate_z = 10
+machine_max_jerk_e = 5
+machine_max_jerk_x = 5
+machine_max_jerk_y = 5
+machine_max_jerk_z = 0.4
+machine_min_extruding_rate = 0
+machine_min_travel_rate = 0
+min_layer_height = 0.05
+nozzle_diameter = 0.4
+parking_pos_retraction = 92
+pause_print_gcode = M601
+print_host = 
+printer_notes = ""
+remaining_times = 1
+retract_before_travel = 1
+retract_before_wipe = 0%
+retract_layer_change = 1
+retract_length = 1
+retract_length_toolchange = 1
+retract_lift = 0
+retract_lift_above = 0
+retract_lift_below = 0
+retract_restart_extra = 0
+retract_restart_extra_toolchange = 0
+retract_speed = 40
+silent_mode = 0
+single_extruder_multi_material = 0
+start_gcode = M104 S0\nM140 S0\nPRINT_START BED={first_layer_bed_temperature[0]} EXTRUDER={first_layer_temperature[0]}
+thumbnails = 64x64,400x300
+toolchange_gcode = 
+use_firmware_retraction = 0
+use_relative_e_distances = 1
+use_volumetric_e = 0
+variable_layer_height = 1
+wipe = 0
+z_offset = 0
+
+
+[printer:*0.4nozzle*]
+nozzle_diameter = 0.4
+max_layer_height = 0.3
+min_layer_height = 0.05
+retract_lift_above = 0.2
+printer_variant = 0.4
+
+[printer:Papapiu N1S]
+inherits = *common*; *0.4nozzle*
+bed_shape = 0x0,299x0,299x300,0x300
+max_print_height = 360
+printer_model = Papapiu_N1S
+
+
+[filament:Generic ABS @Papapiu]
+filament_vendor = Generic
+filament_type = ABS
+bed_temperature = 105
+bridge_fan_speed = 30
+cooling = 0
+disable_fan_first_layers = 2
+end_filament_gcode = "; Filament-specific end gcode \n;END gcode for filament\n"
+extrusion_multiplier = 0.98
+fan_always_on = 0
+fan_below_layer_time = 10
+filament_colour = #3A80CA
+filament_cooling_final_speed = 3.4
+filament_cooling_initial_speed = 2.2
+filament_cooling_moves = 4
+filament_cooling_zone_pause = 0
+filament_cost = 18
+filament_density = 1.04
+filament_deretract_speed = nil
+filament_diameter = 1.75
+filament_load_time = 0
+filament_loading_speed = 28
+filament_loading_speed_start = 3
+filament_max_speed = 0
+filament_max_volumetric_speed = 0
+filament_minimal_purge_on_wipe_tower = 15
+filament_notes = ""
+filament_ramming_parameters = "120 100 6.6 6.8 7.2 7.6 7.9 8.2 8.7 9.4 9.9 10.0| 0.05 6.6 0.45 6.8 0.95 7.8 1.45 8.3 1.95 9.7 2.45 10 2.95 7.6 3.45 7.6 3.95 7.6 4.45 7.6 4.95 7.6"
+filament_retract_layer_change = 0
+filament_retract_length = 0.7
+filament_soluble = 0
+filament_spool_weight = 0
+filament_toolchange_delay = 0
+filament_toolchange_part_fan_speed = 50
+filament_toolchange_temp = 200
+filament_unload_time = 0
+filament_unloading_speed = 90
+filament_unloading_speed_start = 100
+filament_wipe = 1
+first_layer_bed_temperature = 108
+first_layer_temperature = 248
+full_fan_speed_layer = 0
+max_fan_speed = 30
+min_fan_speed = 20
+min_print_speed = 25
+slowdown_below_layer_time = 10
+start_filament_gcode = ""
+temperature = 243
+
+[filament:Generic PETG @Papapiu]
+filament_vendor = Generic
+filament_type = PETG
+bed_temperature = 80
+bridge_fan_speed = 100
+cooling = 0
+disable_fan_first_layers = 3
+end_filament_gcode = "; Filament-specific end gcode \n;END gcode for filament\n"
+extrusion_multiplier = 0.94
+fan_always_on = 1
+fan_below_layer_time = 10
+filament_colour = #FF8000
+filament_cost = 20
+filament_density = 1.27
+filament_diameter = 1.75
+filament_enable_toolchange_part_fan = 0
+filament_enable_toolchange_temp = 0
+filament_load_time = 0
+filament_loading_speed = 28
+filament_loading_speed_start = 3
+filament_max_speed = 0
+filament_max_volumetric_speed = 11
+filament_minimal_purge_on_wipe_tower = 15
+filament_notes = ""
+filament_ramming_parameters = "120 100 6.6 6.8 7.2 7.6 7.9 8.2 8.7 9.4 9.9 10.0| 0.05 6.6 0.45 6.8 0.95 7.8 1.45 8.3 1.95 9.7 2.45 10 2.95 7.6 3.45 7.6 3.95 7.6 4.45 7.6 4.95 7.6"
+filament_retract_layer_change = 1
+filament_retract_length = 1.2
+filament_settings_id = ""
+filament_soluble = 0
+filament_spool_weight = 0
+filament_unload_time = 0
+filament_unloading_speed = 90
+filament_unloading_speed_start = 100
+filament_wipe = 1
+first_layer_bed_temperature = 80
+first_layer_temperature = 240
+full_fan_speed_layer = 0
+max_fan_speed = 100
+min_fan_speed = 40
+min_print_speed = 15
+slowdown_below_layer_time = 10
+start_filament_gcode = ""
+temperature = 235
+
+
+[filament:Generic PLA @Papapiu]
+filament_vendor = Generic
+filament_type = PLA
+bed_temperature = 65
+bridge_fan_speed = 100
+cooling = 0
+disable_fan_first_layers = 2
+end_filament_gcode = "; Filament-specific end gcode \n;END gcode for filament\n"
+extrusion_multiplier = 0.89
+fan_always_on = 1
+fan_below_layer_time = 100
+filament_colour = #FF3232
+filament_cooling_final_speed = 3.4
+filament_cooling_initial_speed = 2.2
+filament_cooling_moves = 4
+filament_cooling_zone_pause = 0
+filament_cost = 20
+filament_density = 1.24
+filament_deretract_speed = nil
+filament_diameter = 1.75
+filament_load_time = 0
+filament_loading_speed = 28
+filament_loading_speed_start = 3
+filament_max_speed = 0
+filament_max_volumetric_speed = 0
+filament_minimal_purge_on_wipe_tower = 15
+filament_notes = ""
+filament_ramming_parameters = "120 100 6.6 6.8 7.2 7.6 7.9 8.2 8.7 9.4 9.9 10.0| 0.05 6.6 0.45 6.8 0.95 7.8 1.45 8.3 1.95 9.7 2.45 10 2.95 7.6 3.45 7.6 3.95 7.6 4.45 7.6 4.95 7.6"
+filament_retract_length = 0.6
+filament_soluble = 0
+filament_spool_weight = 0
+filament_toolchange_delay = 0
+filament_unload_time = 0
+filament_unloading_speed = 90
+filament_unloading_speed_start = 100
+filament_wipe = nil
+first_layer_bed_temperature = 68
+first_layer_temperature = 205
+full_fan_speed_layer = 4
+inherits = 
+max_fan_speed = 100
+min_fan_speed = 100
+min_print_speed = 10
+slowdown_below_layer_time = 15
+start_filament_gcode = ""
+temperature = 195
+
+[filament:Generic TPU @Papapiu]
+inherits = Generic PLA @Papapiu
+bed_temperature = 30
+bridge_fan_speed = 100
+bridge_internal_fan_speed = -1
+chamber_temperature = 0
+compatible_printers = 
+compatible_printers_condition = 
+compatible_prints = 
+compatible_prints_condition = 
+cooling = 0
+disable_fan_first_layers = 2
+end_filament_gcode = "; Filament-specific end gcode \n;END gcode for filament\n"
+external_perimeter_fan_speed = -1
+extrusion_multiplier = 0.89
+fan_always_on = 1
+fan_below_layer_time = 100
+filament_colour = #FF00FF
+filament_cooling_final_speed = 3.4
+filament_cooling_initial_speed = 2.2
+filament_cooling_moves = 4
+filament_cooling_zone_pause = 0
+filament_cost = 20
+filament_custom_variables = ""
+filament_density = 1.24
+filament_deretract_speed = nil
+filament_diameter = 1.75
+filament_dip_extraction_speed = 70
+filament_dip_insertion_speed = 33
+filament_enable_toolchange_part_fan = 0
+filament_enable_toolchange_temp = 0
+filament_load_time = 0
+filament_loading_speed = 28
+filament_loading_speed_start = 3
+filament_max_overlap = 100%
+filament_max_speed = 0
+filament_max_volumetric_speed = 5
+filament_max_wipe_tower_speed = 0
+filament_melt_zone_pause = 0
+filament_minimal_purge_on_wipe_tower = 15
+filament_notes = "This is a profile for TPU95A. It was tested with Anycubic TPU95A, but most of the economy TPU filaments behave pretty similar.\n\nYou will want to optimize the temperature. Even different colors of the same brand can require 10° more or less.\n\nIf you experience clogs or grinding, reduce the maximum volumetric speed!"
+filament_ramming_parameters = "120 100 6.6 6.8 7.2 7.6 7.9 8.2 8.7 9.4 9.9 10.0| 0.05 6.6 0.45 6.8 0.95 7.8 1.45 8.3 1.95 9.7 2.45 10 2.95 7.6 3.45 7.6 3.95 7.6 4.45 7.6 4.95 7.6"
+filament_retract_before_travel = nil
+filament_retract_before_wipe = nil
+filament_retract_layer_change = nil
+filament_retract_length = 1
+filament_retract_lift = 0.1
+filament_retract_lift_above = nil
+filament_retract_lift_below = nil
+filament_retract_restart_extra = nil
+filament_retract_speed = nil
+filament_seam_gap = nil
+filament_shrink = 100%
+filament_skinnydip_distance = 31
+filament_soluble = 0
+filament_spool_weight = 0
+filament_toolchange_delay = 0
+filament_toolchange_part_fan_speed = 50
+filament_toolchange_temp = 200
+filament_type = FLEX
+filament_unload_time = 0
+filament_unloading_speed = 90
+filament_unloading_speed_start = 100
+filament_use_fast_skinnydip = 0
+filament_use_skinnydip = 0
+filament_vendor = Generic
+filament_wipe = nil
+filament_wipe_advanced_pigment = 0.5
+filament_wipe_extra_perimeter = nil
+filament_wipe_only_crossing = nil
+filament_wipe_speed = nil
+first_layer_bed_temperature = 30
+first_layer_temperature = 220
+full_fan_speed_layer = 4
+max_fan_speed = 100
+max_speed_reduction = 95%
+min_fan_speed = 100
+min_print_speed = 10
+slowdown_below_layer_time = 8
+start_filament_gcode = ""
+temperature = 220
+top_fan_speed = -1

resources/profiles/PrusaResearch.idx

@@ -1,4 +1,11 @@
 min_slic3r_version = 2.6.0-beta2
+1.9.8 FW version notification (MK2.5/3 family). Minor update of MK4IS profiles. Updated MK4IS thumbnail.
+1.9.7 MK4 Input Shaper RC firmware notification.
+1.9.6 Added filament profile for Prusament PETG V0.
+1.9.5 Added new profiles for MK4 Input Shaper (Alpha).
+1.9.4 Added profiles for MMU3. Updated PA values for MK4IS. Increased minimal purge on wipe tower for XL Multi-Tool.
+1.9.3 Added material profiles for Prusament Resin Flex80 White.
+1.9.2 Added profiles for Prusa XL Multi-Tool.
 1.9.1 Added new Prusament Resin material profiles.
 1.9.0 Bumped up configuration version.
 1.9.0-beta3 Updated start g-code for MK4 (modified purge line and nozzle cleaning).

sandboxes/CMakeLists.txt

@@ -1,7 +1,8 @@
 #add_subdirectory(slasupporttree)
 #add_subdirectory(openvdb)
 # add_subdirectory(meshboolean)
-add_subdirectory(its_neighbor_index)
+#add_subdirectory(its_neighbor_index)
 # add_subdirectory(opencsg)
 #add_subdirectory(aabb-evaluation)
-add_subdirectory(wx_gl_test)
+#add_subdirectory(wx_gl_test)
+add_subdirectory(print_arrange_polys)

sandboxes/print_arrange_polys/CMakeLists.txt

@@ -0,0 +1,7 @@
+add_executable(print_arrange_polys main.cpp)
+
+target_link_libraries(print_arrange_polys libslic3r admesh)
+
+if (WIN32)
+    prusaslicer_copy_dlls(print_arrange_polys)
+endif()

sandboxes/print_arrange_polys/main.cpp

@@ -0,0 +1,103 @@
+#include <iostream>
+#include <ostream>
+
+#include <libslic3r/TriangleMesh.hpp>
+
+#include <boost/filesystem.hpp>
+
+void print_arrange_polygons(const std::string &dirpath, std::ostream &out)
+{
+    using namespace Slic3r;
+
+    boost::filesystem::path p = dirpath; //"/home/quarky/Workspace/printing/Original-Prusa-i3-MK3/Printed-Parts/stl/";
+
+    if (!boost::filesystem::exists(p) || !boost::filesystem::is_directory(p))
+        return;
+
+    for (const auto& entry : boost::filesystem::directory_iterator(p)) {
+        if (!boost::filesystem::is_regular_file(entry)) {
+            continue;
+        }
+
+        TriangleMesh mesh;
+        mesh.ReadSTLFile(entry.path().c_str());
+        ExPolygons outline = mesh.horizontal_projection();
+
+        out << "// " << entry.path().filename() << ": " << std::endl;
+        for (const ExPolygon &expoly : outline) {
+            out << "MyPoly{\n";  // Start of polygon
+
+            out << "\t{\n";  // Start of contour
+            for (const auto& point : expoly.contour.points) {
+                out << "        {" << point.x() << ", " << point.y() << "},\n";  // Print point coordinates
+            }
+            out << "    },\n";  // End of contour
+
+            out << "    {\n"; // start of holes
+            for (const auto& hole : expoly.holes) {
+                out << "        {\n";  // Start of hole
+                for (const auto& point : hole.points) {
+                    out << "            {" << point.x() << ", " << point.y() << "},\n";  // Print point coordinates
+                }
+                out << "        },\n";  // End of hole Polygon
+            }
+            out << "    }\n"; // end of holes Polygons
+            out << "},\n";  // End of ExPolygon
+        }
+    }
+}
+
+void print_arrange_items(const std::string &dirpath, std::ostream &out)
+{
+    using namespace Slic3r;
+
+    boost::filesystem::path p = dirpath;
+
+    if (!boost::filesystem::exists(p) || !boost::filesystem::is_directory(p))
+        return;
+
+    for (const auto& entry : boost::filesystem::directory_iterator(p)) {
+        if (!boost::filesystem::is_regular_file(entry)) {
+            continue;
+        }
+
+        TriangleMesh mesh;
+        mesh.ReadSTLFile(entry.path().c_str());
+        ExPolygons outline = mesh.horizontal_projection();
+
+        out << "ExPolygons{ " << "// " << entry.path().filename() << ":\n";
+        for (const ExPolygon &expoly : outline) {
+            out << "    MyPoly{\n";  // Start of polygon
+
+            out << "        {\n";  // Start of contour
+            for (const auto& point : expoly.contour.points) {
+                out << "            {" << point.x() << ", " << point.y() << "},\n";  // Print point coordinates
+            }
+            out << "        },\n";  // End of contour
+
+            out << "        {\n"; // start of holes
+            for (const auto& hole : expoly.holes) {
+                out << "            {\n";  // Start of hole
+                for (const auto& point : hole.points) {
+                    out << "                {" << point.x() << ", " << point.y() << "},\n";  // Print point coordinates
+                }
+                out << "            },\n";  // End of hole Polygon
+            }
+            out << "        }\n"; // end of holes Polygons
+            out << "    },\n";  // End of ExPolygon
+        }
+        out << "},\n";
+    }
+}
+
+int main(int argc, const char *argv[])
+{
+    if (argc <= 1)
+        return -1;
+
+    std::string dirpath = argv[1];
+
+    print_arrange_items(dirpath, std::cout);
+
+    return 0;
+}

src/PrusaSlicer.cpp

@@ -40,6 +40,7 @@
 #include "libslic3r/Geometry.hpp"
 #include "libslic3r/GCode/PostProcessor.hpp"
 #include "libslic3r/Model.hpp"
+#include "libslic3r/CutUtils.hpp"
 #include "libslic3r/ModelArrange.hpp"
 #include "libslic3r/Platform.hpp"
 #include "libslic3r/Print.hpp"
@@ -313,10 +314,10 @@ int CLI::run(int argc, char **argv)
     
     // Loop through transform options.
     bool user_center_specified = false;
-    Points bed = get_bed_shape(m_print_config);
-    ArrangeParams arrange_cfg;
-    arrange_cfg.min_obj_distance = scaled(min_object_distance(m_print_config));
-    
+    arr2::ArrangeBed bed = arr2::to_arrange_bed(get_bed_shape(m_print_config));
+    arr2::ArrangeSettings arrange_cfg;
+    arrange_cfg.set_distance_from_objects(min_object_distance(m_print_config));
+
     for (auto const &opt_key : m_transforms) {
         if (opt_key == "merge") {
             Model m;
@@ -329,7 +330,7 @@ int CLI::run(int argc, char **argv)
                 if (this->has_print_action())
                     arrange_objects(m, bed, arrange_cfg);
                 else
-                    arrange_objects(m, InfiniteBed{}, arrange_cfg);
+                    arrange_objects(m, arr2::InfiniteBed{}, arrange_cfg);
             }
             m_models.clear();
             m_models.emplace_back(std::move(m));
@@ -437,8 +438,11 @@ int CLI::run(int argc, char **argv)
                     }
 #else
 //                    model.objects.front()->cut(0, m_config.opt_float("cut"), ModelObjectCutAttribute::KeepLower | ModelObjectCutAttribute::KeepUpper | ModelObjectCutAttribute::FlipLower);
-                    model.objects.front()->cut(0, Geometry::translation_transform(m_config.opt_float("cut") * Vec3d::UnitZ()),
+                    Cut cut(model.objects.front(), 0, Geometry::translation_transform(m_config.opt_float("cut") * Vec3d::UnitZ()),
                                                ModelObjectCutAttribute::KeepLower | ModelObjectCutAttribute::KeepUpper | ModelObjectCutAttribute::PlaceOnCutUpper);
+                    auto cut_objects = cut.perform_with_plane();
+                    for (ModelObject* obj : cut_objects)
+                        model.add_object(*obj);
 #endif
                     model.delete_object(size_t(0));
                 }
@@ -572,7 +576,7 @@ int CLI::run(int argc, char **argv)
                 if (! m_config.opt_bool("dont_arrange")) {
                     if (user_center_specified) {
                         Vec2d c = m_config.option<ConfigOptionPoint>("center")->value;
-                        arrange_objects(model, InfiniteBed{scaled(c)}, arrange_cfg);
+                        arrange_objects(model, arr2::InfiniteBed{scaled(c)}, arrange_cfg);
                     } else
                         arrange_objects(model, bed, arrange_cfg);
                 }

src/imgui/imconfig.h

@@ -152,6 +152,7 @@ namespace ImGui
 //    const wchar_t MmuSegmentationMarker    = 0x1F;
     const wchar_t PlugMarker               = 0x1C;
     const wchar_t DowelMarker              = 0x1D;
+    const wchar_t SnapMarker               = 0x1E;
     // Do not forget use following letters only in wstring
     const wchar_t DocumentationButton      = 0x2600;
     const wchar_t DocumentationHoverButton = 0x2601;

src/libnest2d/CMakeLists.txt

@@ -18,11 +18,10 @@ set(LIBNEST2D_SRCFILES
     include/libnest2d/optimizers/nlopt/simplex.hpp
     include/libnest2d/optimizers/nlopt/subplex.hpp
     include/libnest2d/optimizers/nlopt/genetic.hpp
-    src/libnest2d.cpp
     )
 
-add_library(libnest2d STATIC ${LIBNEST2D_SRCFILES})
+add_library(libnest2d INTERFACE)
 
-target_include_directories(libnest2d PUBLIC ${CMAKE_CURRENT_LIST_DIR}/include)
-target_link_libraries(libnest2d PUBLIC NLopt::nlopt TBB::tbb TBB::tbbmalloc Boost::boost libslic3r)
-target_compile_definitions(libnest2d PUBLIC LIBNEST2D_THREADING_tbb LIBNEST2D_STATIC LIBNEST2D_OPTIMIZER_nlopt LIBNEST2D_GEOMETRIES_libslic3r)
+target_include_directories(libnest2d INTERFACE ${CMAKE_CURRENT_LIST_DIR}/include)
+target_link_libraries(libnest2d INTERFACE NLopt::nlopt TBB::tbb TBB::tbbmalloc Boost::boost libslic3r)
+target_compile_definitions(libnest2d INTERFACE LIBNEST2D_THREADING_tbb LIBNEST2D_STATIC LIBNEST2D_OPTIMIZER_nlopt LIBNEST2D_GEOMETRIES_libslic3r)

src/libnest2d/include/libnest2d/backends/libslic3r/geometries.hpp

@@ -243,6 +243,12 @@ inline void translate(Slic3r::ExPolygon& sh, const Slic3r::Point& offs)
     sh.translate(offs);
 }
 
+template<>
+inline void translate(Slic3r::Polygon& sh, const Slic3r::Point& offs)
+{
+    sh.translate(offs);
+}
+
 #define DISABLE_BOOST_ROTATE
 template<>
 inline void rotate(Slic3r::ExPolygon& sh, const Radians& rads)
@@ -250,6 +256,12 @@ inline void rotate(Slic3r::ExPolygon& sh, const Radians& rads)
     sh.rotate(rads);
 }
 
+template<>
+inline void rotate(Slic3r::Polygon& sh, const Radians& rads)
+{
+    sh.rotate(rads);
+}
+
 } // namespace shapelike
 
 namespace nfp {

src/libslic3r/AnyPtr.hpp

@@ -15,12 +15,19 @@ namespace Slic3r {
 // The stored pointer is not checked for being null when dereferenced.
 //
 // This is a movable only object due to the fact that it can possibly hold
-// a unique_ptr which a non-copy.
+// a unique_ptr which can only be moved.
+//
+// Drawbacks:
+// No custom deleters are supported when storing a unique_ptr, but overloading
+// std::default_delete for a particular type could be a workaround
+//
+// raw array types are problematic, since std::default_delete also does not
+// support them well.
 template<class T>
 class AnyPtr {
-    enum { RawPtr, UPtr, ShPtr, WkPtr };
+    enum { RawPtr, UPtr, ShPtr };
 
-    boost::variant<T*, std::unique_ptr<T>, std::shared_ptr<T>, std::weak_ptr<T>> ptr;
+    boost::variant<T*, std::unique_ptr<T>, std::shared_ptr<T>> ptr;
 
     template<class Self> static T *get_ptr(Self &&s)
     {
@@ -28,91 +35,119 @@ class AnyPtr {
         case RawPtr: return boost::get<T *>(s.ptr);
         case UPtr: return boost::get<std::unique_ptr<T>>(s.ptr).get();
         case ShPtr: return boost::get<std::shared_ptr<T>>(s.ptr).get();
-        case WkPtr: {
-            auto shptr = boost::get<std::weak_ptr<T>>(s.ptr).lock();
-            return shptr.get();
-        }
         }
 
         return nullptr;
     }
 
-public:
-    template<class TT = T, class = std::enable_if_t<std::is_convertible_v<TT*, T*>>>
-    AnyPtr(TT *p = nullptr) : ptr{p}
-    {}
-    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT*, T*>>>
-    AnyPtr(std::unique_ptr<TT> p) : ptr{std::unique_ptr<T>(std::move(p))}
-    {}
-    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT*, T*>>>
-    AnyPtr(std::shared_ptr<TT> p) : ptr{std::shared_ptr<T>(std::move(p))}
-    {}
-    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT*, T*>>>
-    AnyPtr(std::weak_ptr<TT> p) : ptr{std::weak_ptr<T>(std::move(p))}
-    {}
+    template<class TT> friend class AnyPtr;
 
-    ~AnyPtr() = default;
+    template<class TT>
+    using SimilarPtrOnly = std::enable_if_t<std::is_convertible_v<TT*, T*>>;
+
+public:
+
+    AnyPtr() noexcept = default;
+
+    AnyPtr(T *p) noexcept: ptr{p} {}
+
+    AnyPtr(std::nullptr_t) noexcept {};
+
+    template<class TT, class = SimilarPtrOnly<TT>>
+    AnyPtr(TT *p) noexcept : ptr{p}
+    {}
+    template<class TT = T, class = SimilarPtrOnly<TT>>
+    AnyPtr(std::unique_ptr<TT> p) noexcept : ptr{std::unique_ptr<T>(std::move(p))}
+    {}
+    template<class TT = T, class = SimilarPtrOnly<TT>>
+    AnyPtr(std::shared_ptr<TT> p) noexcept : ptr{std::shared_ptr<T>(std::move(p))}
+    {}
 
     AnyPtr(AnyPtr &&other) noexcept : ptr{std::move(other.ptr)} {}
+
+    template<class TT, class = SimilarPtrOnly<TT>>
+    AnyPtr(AnyPtr<TT> &&other) noexcept
+    {
+        this->operator=(std::move(other));
+    }
+
     AnyPtr(const AnyPtr &other) = delete;
 
-    AnyPtr &operator=(AnyPtr &&other) noexcept { ptr = std::move(other.ptr); return *this; }
+    AnyPtr &operator=(AnyPtr &&other) noexcept
+    {
+        ptr = std::move(other.ptr);
+        return *this;
+    }
+
     AnyPtr &operator=(const AnyPtr &other) = delete;
 
-    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT*, T*>>>
-    AnyPtr &operator=(TT *p) { ptr = p; return *this; }
+    template<class TT, class = SimilarPtrOnly<TT>>
+    AnyPtr& operator=(AnyPtr<TT> &&other) noexcept
+    {
+        switch (other.ptr.which()) {
+        case RawPtr: *this = boost::get<TT *>(other.ptr); break;
+        case UPtr: *this = std::move(boost::get<std::unique_ptr<TT>>(other.ptr)); break;
+        case ShPtr: *this = std::move(boost::get<std::shared_ptr<TT>>(other.ptr)); break;
+        }
 
-    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT*, T*>>>
-    AnyPtr &operator=(std::unique_ptr<TT> p) { ptr = std::move(p); return *this; }
+        return *this;
+    }
 
-    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT*, T*>>>
-    AnyPtr &operator=(std::shared_ptr<TT> p) { ptr = p; return *this; }
+    template<class TT, class = SimilarPtrOnly<TT>>
+    AnyPtr &operator=(TT *p) noexcept
+    {
+        ptr = static_cast<T *>(p);
+        return *this;
+    }
 
-    template<class TT, class = std::enable_if_t<std::is_convertible_v<TT*, T*>>>
-    AnyPtr &operator=(std::weak_ptr<TT> p) { ptr = std::move(p); return *this; }
+    template<class TT, class = SimilarPtrOnly<TT>>
+    AnyPtr &operator=(std::unique_ptr<TT> p) noexcept
+    {
+        ptr = std::unique_ptr<T>(std::move(p));
+        return *this;
+    }
 
-    const T &operator*() const { return *get_ptr(*this); }
-    T &operator*() { return *get_ptr(*this); }
+    template<class TT, class = SimilarPtrOnly<TT>>
+    AnyPtr &operator=(std::shared_ptr<TT> p) noexcept
+    {
+        ptr = std::shared_ptr<T>(std::move(p));
+        return *this;
+    }
 
-    T *operator->() { return get_ptr(*this); }
-    const T *operator->() const { return get_ptr(*this); }
+    const T &operator*() const noexcept { return *get_ptr(*this); }
+    T &operator*() noexcept { return *get_ptr(*this); }
 
-    T *get() { return get_ptr(*this); }
-    const T *get() const { return get_ptr(*this); }
+    T *operator->() noexcept { return get_ptr(*this); }
+    const T *operator->() const noexcept { return get_ptr(*this); }
 
-    operator bool() const
+    T *get() noexcept { return get_ptr(*this); }
+    const T *get() const noexcept { return get_ptr(*this); }
+
+    operator bool() const noexcept
     {
         switch (ptr.which()) {
         case RawPtr: return bool(boost::get<T *>(ptr));
         case UPtr: return bool(boost::get<std::unique_ptr<T>>(ptr));
         case ShPtr: return bool(boost::get<std::shared_ptr<T>>(ptr));
-        case WkPtr: {
-            auto shptr = boost::get<std::weak_ptr<T>>(ptr).lock();
-            return bool(shptr);
-        }
         }
 
         return false;
     }
 
-    // If the stored pointer is a shared or weak pointer, returns a reference
+    // If the stored pointer is a shared pointer, returns a reference
     // counted copy. Empty shared pointer is returned otherwise.
-    std::shared_ptr<T> get_shared_cpy() const
+    std::shared_ptr<T> get_shared_cpy() const noexcept
     {
         std::shared_ptr<T> ret;
 
-        switch (ptr.which()) {
-        case ShPtr: ret = boost::get<std::shared_ptr<T>>(ptr); break;
-        case WkPtr: ret = boost::get<std::weak_ptr<T>>(ptr).lock(); break;
-        default:
-            ;
-        }
+        if (ptr.which() == ShPtr)
+            ret = boost::get<std::shared_ptr<T>>(ptr);
 
         return ret;
     }
 
     // If the underlying pointer is unique, convert to shared pointer
-    void convert_unique_to_shared()
+    void convert_unique_to_shared() noexcept
     {
         if (ptr.which() == UPtr)
             ptr = std::shared_ptr<T>{std::move(boost::get<std::unique_ptr<T>>(ptr))};
@@ -125,6 +160,7 @@ public:
     }
 };
 
+
 } // namespace Slic3r
 
 #endif // ANYPTR_HPP

src/libslic3r/Arrange.cpp

@@ -12,6 +12,7 @@
 #include <ClipperUtils.hpp>
 
 #include <boost/geometry/index/rtree.hpp>
+#include <boost/container/small_vector.hpp>
 
 #if defined(_MSC_VER) && defined(__clang__)
 #define BOOST_NO_CXX17_HDR_STRING_VIEW
@@ -258,7 +259,7 @@ protected:
             auto& index = isBig(item.area()) ? spatindex : smalls_spatindex;
 
             // Query the spatial index for the neighbors
-            std::vector<SpatElement> result;
+            boost::container::small_vector<SpatElement, 100> result;
             result.reserve(index.size());
 
             index.query(query, std::back_inserter(result));

src/libslic3r/Arrange/Arrange.hpp

@@ -0,0 +1,268 @@
+#ifndef ARRANGE2_HPP
+#define ARRANGE2_HPP
+
+#include "Scene.hpp"
+#include "Items/MutableItemTraits.hpp"
+#include "Core/NFP/NFPArrangeItemTraits.hpp"
+
+#include "libslic3r/MinAreaBoundingBox.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+template<class ArrItem> class Arranger
+{
+public:
+    class Ctl : public ArrangeTaskCtl {
+    public:
+        virtual void on_packed(ArrItem &item) {};
+    };
+
+    virtual ~Arranger() = default;
+
+    virtual void arrange(std::vector<ArrItem> &items,
+                         const std::vector<ArrItem> &fixed,
+                         const ExtendedBed &bed,
+                         Ctl &ctl) = 0;
+
+    void arrange(std::vector<ArrItem> &items,
+                 const std::vector<ArrItem> &fixed,
+                 const ExtendedBed &bed,
+                 ArrangeTaskCtl &ctl);
+
+    void arrange(std::vector<ArrItem> &items,
+                 const std::vector<ArrItem> &fixed,
+                 const ExtendedBed &bed,
+                 Ctl &&ctl)
+    {
+        arrange(items, fixed, bed, ctl);
+    }
+
+    void arrange(std::vector<ArrItem> &items,
+                 const std::vector<ArrItem> &fixed,
+                 const ExtendedBed &bed,
+                 ArrangeTaskCtl &&ctl)
+    {
+        arrange(items, fixed, bed, ctl);
+    }
+
+    static std::unique_ptr<Arranger> create(const ArrangeSettingsView &settings);
+};
+
+template<class ArrItem> using ArrangerCtl = typename Arranger<ArrItem>::Ctl;
+
+template<class ArrItem>
+class DefaultArrangerCtl : public Arranger<ArrItem>::Ctl {
+    ArrangeTaskCtl *taskctl = nullptr;
+
+public:
+    DefaultArrangerCtl() = default;
+
+    explicit DefaultArrangerCtl(ArrangeTaskBase::Ctl &ctl) : taskctl{&ctl} {}
+
+    void update_status(int st) override
+    {
+        if (taskctl)
+            taskctl->update_status(st);
+    }
+
+    bool was_canceled() const override
+    {
+        if (taskctl)
+            return taskctl->was_canceled();
+
+        return false;
+    }
+};
+
+template<class ArrItem>
+void Arranger<ArrItem>::arrange(std::vector<ArrItem> &items,
+             const std::vector<ArrItem> &fixed,
+             const ExtendedBed &bed,
+             ArrangeTaskCtl &ctl)
+{
+    arrange(items, fixed, bed, DefaultArrangerCtl<ArrItem>{ctl});
+}
+
+class EmptyItemOutlineError: public std::exception {
+    static constexpr const char *Msg = "No outline can be derived for object";
+
+public:
+    const char* what() const noexcept override { return Msg; }
+};
+
+template<class ArrItem> class ArrangeableToItemConverter
+{
+public:
+    virtual ~ArrangeableToItemConverter() = default;
+
+    // May throw EmptyItemOutlineError
+    virtual ArrItem convert(const Arrangeable &arrbl, coord_t offs = 0) const = 0;
+
+    // Returns the extent of simplification that the converter utilizes when
+    // creating arrange items. Zero shall mean no simplification at all.
+    virtual coord_t simplification_tolerance() const { return 0; }
+
+    static std::unique_ptr<ArrangeableToItemConverter> create(
+        ArrangeSettingsView::GeometryHandling geometry_handling,
+        coord_t                               safety_d);
+
+    static std::unique_ptr<ArrangeableToItemConverter> create(
+        const Scene &sc)
+    {
+        return create(sc.settings().get_geometry_handling(),
+                      scaled(sc.settings().get_distance_from_objects()));
+    }
+};
+
+template<class DStore, class = WritableDataStoreOnly<DStore>>
+class AnyWritableDataStore: public AnyWritable
+{
+    DStore &dstore;
+
+public:
+    AnyWritableDataStore(DStore &store): dstore{store} {}
+
+    void write(std::string_view key, std::any d) override
+    {
+        set_data(dstore, std::string{key}, std::move(d));
+    }
+};
+
+template<class ArrItem>
+class BasicItemConverter : public ArrangeableToItemConverter<ArrItem>
+{
+    coord_t m_safety_d;
+    coord_t m_simplify_tol;
+
+public:
+    BasicItemConverter(coord_t safety_d = 0, coord_t simpl_tol = 0)
+        : m_safety_d{safety_d}, m_simplify_tol{simpl_tol}
+    {}
+
+    coord_t safety_dist() const noexcept { return m_safety_d; }
+
+    coord_t simplification_tolerance() const override
+    {
+        return m_simplify_tol;
+    }
+};
+
+template<class ArrItem>
+class ConvexItemConverter : public BasicItemConverter<ArrItem>
+{
+public:
+    using BasicItemConverter<ArrItem>::BasicItemConverter;
+
+    ArrItem convert(const Arrangeable &arrbl, coord_t offs) const override;
+};
+
+template<class ArrItem>
+class AdvancedItemConverter : public BasicItemConverter<ArrItem>
+{
+protected:
+    virtual ArrItem get_arritem(const Arrangeable &arrbl, coord_t eps) const;
+
+public:
+    using BasicItemConverter<ArrItem>::BasicItemConverter;
+
+    ArrItem convert(const Arrangeable &arrbl, coord_t offs) const override;
+};
+
+template<class ArrItem>
+class BalancedItemConverter : public AdvancedItemConverter<ArrItem>
+{
+protected:
+    ArrItem get_arritem(const Arrangeable &arrbl, coord_t offs) const override;
+
+public:
+    using AdvancedItemConverter<ArrItem>::AdvancedItemConverter;
+};
+
+template<class ArrItem, class En = void> struct ImbueableItemTraits_
+{
+    static constexpr const char *Key = "object_id";
+
+    static void imbue_id(ArrItem &itm, const ObjectID &id)
+    {
+        set_arbitrary_data(itm, Key, id);
+    }
+
+    static std::optional<ObjectID> retrieve_id(const ArrItem &itm)
+    {
+        std::optional<ObjectID> ret;
+        auto                    idptr = get_data<const ObjectID>(itm, Key);
+        if (idptr)
+            ret = *idptr;
+
+        return ret;
+    }
+};
+
+template<class ArrItem>
+using ImbueableItemTraits = ImbueableItemTraits_<StripCVRef<ArrItem>>;
+
+template<class ArrItem>
+void imbue_id(ArrItem &itm, const ObjectID &id)
+{
+    ImbueableItemTraits<ArrItem>::imbue_id(itm, id);
+}
+
+template<class ArrItem>
+std::optional<ObjectID> retrieve_id(const ArrItem &itm)
+{
+    return ImbueableItemTraits<ArrItem>::retrieve_id(itm);
+}
+
+template<class ArrItem>
+bool apply_arrangeitem(const ArrItem &itm, ArrangeableModel &mdl)
+{
+    bool ret = false;
+
+    if (auto id = retrieve_id(itm)) {
+        mdl.visit_arrangeable(*id, [&itm, &ret](Arrangeable &arrbl) {
+            if ((ret = arrbl.assign_bed(get_bed_index(itm))))
+                arrbl.transform(unscaled(get_translation(itm)), get_rotation(itm));
+        });
+    }
+
+    return ret;
+}
+
+template<class ArrItem>
+double get_min_area_bounding_box_rotation(const ArrItem &itm)
+{
+    return MinAreaBoundigBox{envelope_convex_hull(itm),
+                             MinAreaBoundigBox::pcConvex}
+        .angle_to_X();
+}
+
+template<class ArrItem>
+double get_fit_into_bed_rotation(const ArrItem &itm, const RectangleBed &bed)
+{
+    double ret = 0.;
+
+    auto bbsz = envelope_bounding_box(itm).size();
+    auto binbb = bounding_box(bed);
+    auto binbbsz = binbb.size();
+
+    if (bbsz.x() >= binbbsz.x() || bbsz.y() >= binbbsz.y())
+        ret = fit_into_box_rotation(envelope_convex_hull(itm), binbb);
+
+    return ret;
+}
+
+template<class ArrItem>
+auto get_corrected_bed(const ExtendedBed &bed,
+                       const ArrangeableToItemConverter<ArrItem> &converter)
+{
+    auto bedcpy = bed;
+    visit_bed([tol = -converter.simplification_tolerance()](auto &rawbed) {
+        rawbed = offset(rawbed, tol);
+    }, bedcpy);
+
+    return bedcpy;
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGE2_HPP

src/libslic3r/Arrange/ArrangeImpl.hpp

@@ -0,0 +1,497 @@
+#ifndef ARRANGEIMPL_HPP
+#define ARRANGEIMPL_HPP
+
+#include <random>
+#include <map>
+
+#include "Arrange.hpp"
+
+#include "Core/ArrangeBase.hpp"
+#include "Core/ArrangeFirstFit.hpp"
+#include "Core/NFP/PackStrategyNFP.hpp"
+#include "Core/NFP/Kernels/TMArrangeKernel.hpp"
+#include "Core/NFP/Kernels/GravityKernel.hpp"
+#include "Core/NFP/RectangleOverfitPackingStrategy.hpp"
+#include "Core/Beds.hpp"
+
+#include "Items/MutableItemTraits.hpp"
+
+#include "SegmentedRectangleBed.hpp"
+
+#include "libslic3r/Execution/ExecutionTBB.hpp"
+#include "libslic3r/Geometry/ConvexHull.hpp"
+
+#ifndef NDEBUG
+#include "Core/NFP/Kernels/SVGDebugOutputKernelWrapper.hpp"
+#endif
+
+namespace Slic3r { namespace arr2 {
+
+// arrange overload for SegmentedRectangleBed which is exactly what is used
+// by XL printers.
+template<class It,
+         class ConstIt,
+         class SelectionStrategy,
+         class PackStrategy, class...SBedArgs>
+void arrange(SelectionStrategy &&selstrategy,
+             PackStrategy &&packingstrategy,
+             const Range<It> &items,
+             const Range<ConstIt> &fixed,
+             const SegmentedRectangleBed<SBedArgs...> &bed)
+{
+    // Dispatch:
+    arrange(std::forward<SelectionStrategy>(selstrategy),
+            std::forward<PackStrategy>(packingstrategy), items, fixed,
+            RectangleBed{bed.bb}, SelStrategyTag<SelectionStrategy>{});
+
+    std::vector<int> bed_indices = get_bed_indices(items, fixed);
+    std::map<int, BoundingBox> pilebb;
+    std::map<int, bool> bed_occupied;
+
+    for (auto &itm : items) {
+        auto bedidx = get_bed_index(itm);
+        if (bedidx >= 0) {
+            pilebb[bedidx].merge(fixed_bounding_box(itm));
+            if (is_wipe_tower(itm))
+                bed_occupied[bedidx] = true;
+        }
+    }
+
+    for (auto &fxitm : fixed) {
+        auto bedidx = get_bed_index(fxitm);
+        if (bedidx >= 0)
+            bed_occupied[bedidx] = true;
+    }
+
+    auto bedbb = bounding_box(bed);
+    auto piecesz = unscaled(bedbb).size();
+    piecesz.x() /= bed.segments_x();
+    piecesz.y() /= bed.segments_y();
+
+    using Pivots = RectPivots;
+
+    Pivots pivot = bed.alignment();
+
+    for (int bedidx : bed_indices) {
+        if (auto occup_it = bed_occupied.find(bedidx);
+            occup_it != bed_occupied.end() && occup_it->second)
+            continue;
+
+        BoundingBox bb;
+        auto pilesz = unscaled(pilebb[bedidx]).size();
+        bb.max.x() = scaled(std::ceil(pilesz.x() / piecesz.x()) * piecesz.x());
+        bb.max.y() = scaled(std::ceil(pilesz.y() / piecesz.y()) * piecesz.y());
+
+        switch (pivot) {
+        case Pivots::BottomLeft:
+            bb.translate(bedbb.min - bb.min);
+            break;
+        case Pivots::TopRight:
+            bb.translate(bedbb.max - bb.max);
+            break;
+        case Pivots::BottomRight: {
+            Point bedref{bedbb.max.x(), bedbb.min.y()};
+            Point bbref {bb.max.x(), bb.min.y()};
+            bb.translate(bedref - bbref);
+            break;
+        }
+        case Pivots::TopLeft: {
+            Point bedref{bedbb.min.x(), bedbb.max.y()};
+            Point bbref {bb.min.x(), bb.max.y()};
+            bb.translate(bedref - bbref);
+            break;
+        }
+        case Pivots::Center: {
+            bb.translate(bedbb.center() - bb.center());
+            break;
+        }
+        default:
+            ;
+        }
+
+        Vec2crd d = bb.center() - pilebb[bedidx].center();
+
+        auto pilebbx = pilebb[bedidx];
+        pilebbx.translate(d);
+
+        Point corr{0, 0};
+        corr.x() = -std::min(0, pilebbx.min.x() - bedbb.min.x())
+                   -std::max(0, pilebbx.max.x() - bedbb.max.x());
+        corr.y() = -std::min(0, pilebbx.min.y() - bedbb.min.y())
+                   -std::max(0, pilebbx.max.y() - bedbb.max.y());
+
+        d += corr;
+
+        for (auto &itm : items)
+            if (get_bed_index(itm) == static_cast<int>(bedidx) && !is_wipe_tower(itm))
+                translate(itm, d);
+    }
+}
+
+
+using VariantKernel =
+    boost::variant<TMArrangeKernel, GravityKernel>;
+
+template<> struct KernelTraits_<VariantKernel> {
+    template<class ArrItem>
+    static double placement_fitness(const VariantKernel &kernel,
+                                    const ArrItem &itm,
+                                    const Vec2crd &transl)
+    {
+        double ret = NaNd;
+        boost::apply_visitor(
+            [&](auto &k) { ret = k.placement_fitness(itm, transl); }, kernel);
+
+        return ret;
+    }
+
+    template<class ArrItem, class Bed, class Ctx, class RemIt>
+    static bool on_start_packing(VariantKernel &kernel,
+                                 ArrItem &itm,
+                                 const Bed &bed,
+                                 const Ctx &packing_context,
+                                 const Range<RemIt> &remaining_items)
+    {
+        bool ret = false;
+
+        boost::apply_visitor([&](auto &k) {
+            ret = k.on_start_packing(itm, bed, packing_context, remaining_items);
+        }, kernel);
+
+        return ret;
+    }
+
+    template<class ArrItem>
+    static bool on_item_packed(VariantKernel &kernel, ArrItem &itm)
+    {
+        bool ret = false;
+        boost::apply_visitor([&](auto &k) { ret = k.on_item_packed(itm); },
+                             kernel);
+
+        return ret;
+    }
+};
+
+template<class ArrItem>
+struct firstfit::ItemArrangedVisitor<ArrItem, DataStoreOnly<ArrItem>> {
+    template<class Bed, class PIt, class RIt>
+    static void on_arranged(ArrItem &itm,
+                            const Bed &bed,
+                            const Range<PIt> &packed,
+                            const Range<RIt> &remaining)
+    {
+        using OnArrangeCb = std::function<void(StripCVRef<ArrItem> &)>;
+
+        auto cb = get_data<OnArrangeCb>(itm, "on_arranged");
+
+        if (cb) {
+            (*cb)(itm);
+        }
+    }
+};
+
+inline RectPivots xlpivots_to_rect_pivots(ArrangeSettingsView::XLPivots xlpivot)
+{
+    if (xlpivot == arr2::ArrangeSettingsView::xlpRandom) {
+        // means it should be random
+        std::random_device rd{};
+        std::mt19937 rng(rd());
+        std::uniform_int_distribution<std::mt19937::result_type>
+            dist(0, arr2::ArrangeSettingsView::xlpRandom - 1);
+        xlpivot = static_cast<ArrangeSettingsView::XLPivots>(dist(rng));
+    }
+
+    RectPivots rectpivot = RectPivots::Center;
+
+    switch(xlpivot) {
+    case arr2::ArrangeSettingsView::xlpCenter: rectpivot = RectPivots::Center; break;
+    case arr2::ArrangeSettingsView::xlpFrontLeft: rectpivot = RectPivots::BottomLeft; break;
+    case arr2::ArrangeSettingsView::xlpFrontRight: rectpivot = RectPivots::BottomRight; break;
+    case arr2::ArrangeSettingsView::xlpRearLeft: rectpivot = RectPivots::TopLeft; break;
+    case arr2::ArrangeSettingsView::xlpRearRight: rectpivot = RectPivots::TopRight; break;
+    default:
+        ;
+    }
+
+    return rectpivot;
+}
+
+template<class It, class Bed>
+void fill_rotations(const Range<It>           &items,
+                    const Bed                 &bed,
+                    const ArrangeSettingsView &settings)
+{
+    if (!settings.is_rotation_enabled())
+        return;
+
+    for (auto &itm : items) {
+        if (is_wipe_tower(itm)) // Rotating the wipe tower is currently problematic
+            continue;
+
+        // Use the minimum bounding box rotation as a starting point.
+        auto minbbr = get_min_area_bounding_box_rotation(itm);
+        std::vector<double> rotations =
+            {minbbr,
+             minbbr + PI / 4., minbbr + PI / 2.,
+             minbbr + PI,      minbbr + 3 * PI / 4.};
+
+        // Add the original rotation of the item if minbbr
+        // is not already the original rotation (zero)
+        if (std::abs(minbbr) > 0.)
+            rotations.emplace_back(0.);
+
+        // Also try to find the rotation that fits the item
+        // into a rectangular bed, given that it cannot fit,
+        // and there exists a rotation which can fit.
+        if constexpr (std::is_convertible_v<Bed, RectangleBed>) {
+            double fitbrot = get_fit_into_bed_rotation(itm, bed);
+            if (std::abs(fitbrot) > 0.)
+                rotations.emplace_back(fitbrot);
+        }
+
+        set_allowed_rotations(itm, rotations);
+    }
+}
+
+// An arranger put together to fulfill all the requirements of PrusaSlicer based
+// on the supplied ArrangeSettings
+template<class ArrItem>
+class DefaultArranger: public Arranger<ArrItem> {
+    ArrangeSettings m_settings;
+
+    static constexpr auto Accuracy = 1.;
+
+    template<class It, class FixIt, class Bed>
+    void arrange_(
+        const Range<It>     &items,
+        const Range<FixIt>  &fixed,
+        const Bed &bed,
+        ArrangerCtl<ArrItem> &ctl)
+    {
+        auto cmpfn = [](const auto &itm1, const auto &itm2) {
+            int pa = get_priority(itm1);
+            int pb = get_priority(itm2);
+
+            return pa == pb ? area(envelope_convex_hull(itm1)) > area(envelope_convex_hull(itm2)) :
+                              pa > pb;
+        };
+
+        auto on_arranged = [&ctl](auto &itm, auto &bed, auto &ctx, auto &rem) {
+            ctl.update_status(rem.size());
+
+            ctl.on_packed(itm);
+
+            firstfit::DefaultOnArrangedFn{}(itm, bed, ctx, rem);
+        };
+
+        auto stop_cond = [&ctl] { return ctl.was_canceled(); };
+
+        firstfit::SelectionStrategy sel{cmpfn, on_arranged, stop_cond};
+
+        constexpr auto ep = ex_tbb;
+
+        VariantKernel basekernel;
+        switch (m_settings.get_arrange_strategy()) {
+        default:
+            [[fallthrough]];
+        case ArrangeSettingsView::asAuto:
+            if constexpr (std::is_convertible_v<Bed, CircleBed>){
+                basekernel = GravityKernel{};
+            } else {
+                basekernel = TMArrangeKernel{items.size(), area(bed)};
+            }
+            break;
+        case ArrangeSettingsView::asPullToCenter:
+            basekernel = GravityKernel{};
+            break;
+        }
+
+#ifndef NDEBUG
+        SVGDebugOutputKernelWrapper<VariantKernel> kernel{bounding_box(bed), basekernel};
+#else
+        auto & kernel = basekernel;
+#endif
+
+        fill_rotations(items, bed, m_settings);
+
+        bool with_wipe_tower = std::any_of(items.begin(), items.end(),
+                                           [](auto &itm) {
+                                               return is_wipe_tower(itm);
+                                           });
+
+        // With rectange bed, and no fixed items, let's use an infinite bed
+        // with RectangleOverfitKernelWrapper. It produces better results than
+        // a pure RectangleBed with inner-fit polygon calculation.
+        if (!with_wipe_tower &&
+            m_settings.get_arrange_strategy() == ArrangeSettingsView::asAuto &&
+            std::is_convertible_v<Bed, RectangleBed>) {
+            PackStrategyNFP base_strategy{std::move(kernel), ep, Accuracy, stop_cond};
+
+            RectangleOverfitPackingStrategy final_strategy{std::move(base_strategy)};
+
+            arr2::arrange(sel, final_strategy, items, fixed, bed);
+        } else {
+            PackStrategyNFP ps{std::move(kernel), ep, Accuracy, stop_cond};
+
+            arr2::arrange(sel, ps, items, fixed, bed);
+        }
+    }
+
+public:
+    explicit DefaultArranger(const ArrangeSettingsView &settings)
+    {
+        m_settings.set_from(settings);
+    }
+
+    void arrange(
+        std::vector<ArrItem> &items,
+        const std::vector<ArrItem> &fixed,
+        const ExtendedBed &bed,
+        ArrangerCtl<ArrItem> &ctl) override
+    {
+        visit_bed([this, &items, &fixed, &ctl](auto rawbed) {
+
+            if constexpr (IsSegmentedBed<decltype(rawbed)>)
+                rawbed.pivot = xlpivots_to_rect_pivots(
+                    m_settings.get_xl_alignment());
+
+            arrange_(range(items), crange(fixed), rawbed, ctl);
+        }, bed);
+    }
+};
+
+template<class ArrItem>
+std::unique_ptr<Arranger<ArrItem>> Arranger<ArrItem>::create(
+    const ArrangeSettingsView &settings)
+{
+    // Currently all that is needed is handled by DefaultArranger
+    return std::make_unique<DefaultArranger<ArrItem>>(settings);
+}
+
+template<class ArrItem>
+ArrItem ConvexItemConverter<ArrItem>::convert(const Arrangeable &arrbl,
+                                              coord_t offs) const
+{
+    auto bed_index = arrbl.get_bed_index();
+    Polygon outline = arrbl.convex_outline();
+
+    if (outline.empty())
+        throw EmptyItemOutlineError{};
+
+    Polygon envelope = arrbl.convex_envelope();
+
+    coord_t infl = offs + coord_t(std::ceil(this->safety_dist() / 2.));
+
+    if (infl != 0) {
+        outline = Geometry::convex_hull(offset(outline, infl));
+        if (! envelope.empty())
+            envelope = Geometry::convex_hull(offset(envelope, infl));
+    }
+
+    ArrItem ret;
+    set_convex_shape(ret, outline);
+    if (! envelope.empty())
+        set_convex_envelope(ret, envelope);
+
+    set_bed_index(ret, bed_index);
+    set_priority(ret, arrbl.priority());
+
+    imbue_id(ret, arrbl.id());
+    if constexpr (IsWritableDataStore<ArrItem>)
+        arrbl.imbue_data(AnyWritableDataStore{ret});
+
+    return ret;
+}
+
+template<class ArrItem>
+ArrItem AdvancedItemConverter<ArrItem>::convert(const Arrangeable &arrbl,
+                                                coord_t offs) const
+{
+    auto bed_index = arrbl.get_bed_index();
+    ArrItem ret = get_arritem(arrbl, offs);
+
+    set_bed_index(ret, bed_index);
+    set_priority(ret, arrbl.priority());
+    imbue_id(ret, arrbl.id());
+    if constexpr (IsWritableDataStore<ArrItem>)
+        arrbl.imbue_data(AnyWritableDataStore{ret});
+
+    return ret;
+}
+
+template<class ArrItem>
+ArrItem AdvancedItemConverter<ArrItem>::get_arritem(const Arrangeable &arrbl,
+                                                    coord_t    offs) const
+{
+    coord_t infl = offs + coord_t(std::ceil(this->safety_dist() / 2.));
+
+    auto outline = arrbl.full_outline();
+
+    if (outline.empty())
+        throw EmptyItemOutlineError{};
+
+    auto envelope = arrbl.full_envelope();
+
+    if (infl != 0) {
+        outline = offset_ex(outline, infl);
+        if (! envelope.empty())
+            envelope = offset_ex(envelope, infl);
+    }
+
+    auto simpl_tol = static_cast<double>(this->simplification_tolerance());
+
+    if (simpl_tol > 0)
+    {
+        outline = expolygons_simplify(outline, simpl_tol);
+        if (!envelope.empty())
+            envelope = expolygons_simplify(envelope, simpl_tol);
+    }
+
+    ArrItem ret;
+    set_shape(ret, outline);
+    if (! envelope.empty())
+        set_envelope(ret, envelope);
+
+    return ret;
+}
+
+template<class ArrItem>
+ArrItem BalancedItemConverter<ArrItem>::get_arritem(const Arrangeable &arrbl,
+                                                    coord_t    offs) const
+{
+    ArrItem ret = AdvancedItemConverter<ArrItem>::get_arritem(arrbl, offs);
+    set_convex_envelope(ret, envelope_convex_hull(ret));
+
+    return ret;
+}
+
+template<class ArrItem>
+std::unique_ptr<ArrangeableToItemConverter<ArrItem>>
+ArrangeableToItemConverter<ArrItem>::create(
+    ArrangeSettingsView::GeometryHandling gh,
+    coord_t safety_d)
+{
+    std::unique_ptr<ArrangeableToItemConverter<ArrItem>> ret;
+
+    constexpr coord_t SimplifyTol = scaled(.2);
+
+    switch(gh) {
+    case arr2::ArrangeSettingsView::ghConvex:
+        ret = std::make_unique<ConvexItemConverter<ArrItem>>(safety_d);
+        break;
+    case arr2::ArrangeSettingsView::ghBalanced:
+        ret = std::make_unique<BalancedItemConverter<ArrItem>>(safety_d, SimplifyTol);
+        break;
+    case arr2::ArrangeSettingsView::ghAdvanced:
+        ret = std::make_unique<AdvancedItemConverter<ArrItem>>(safety_d, SimplifyTol);
+        break;
+    default:
+        ;
+    }
+
+    return ret;
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGEIMPL_HPP

src/libslic3r/Arrange/ArrangeSettingsDb_AppCfg.cpp

@@ -0,0 +1,197 @@
+#include "ArrangeSettingsDb_AppCfg.hpp"
+
+namespace Slic3r {
+
+ArrangeSettingsDb_AppCfg::ArrangeSettingsDb_AppCfg(AppConfig *appcfg) : m_appcfg{appcfg}
+{
+    m_settings_fff.postfix = "_fff";
+    m_settings_fff_seq.postfix = "_fff_seq_print";
+    m_settings_sla.postfix = "_sla";
+
+    std::string dist_fff_str =
+        m_appcfg->get("arrange", "min_object_distance_fff");
+
+    std::string dist_bed_fff_str =
+        m_appcfg->get("arrange", "min_bed_distance_fff");
+
+    std::string dist_fff_seq_print_str =
+        m_appcfg->get("arrange", "min_object_distance_fff_seq_print");
+
+    std::string dist_bed_fff_seq_print_str =
+        m_appcfg->get("arrange", "min_bed_distance_fff_seq_print");
+
+    std::string dist_sla_str =
+        m_appcfg->get("arrange", "min_object_distance_sla");
+
+    std::string dist_bed_sla_str =
+        m_appcfg->get("arrange", "min_bed_distance_sla");
+
+    std::string en_rot_fff_str =
+        m_appcfg->get("arrange", "enable_rotation_fff");
+
+    std::string en_rot_fff_seqp_str =
+        m_appcfg->get("arrange", "enable_rotation_fff_seq_print");
+
+    std::string en_rot_sla_str =
+        m_appcfg->get("arrange", "enable_rotation_sla");
+
+    //    std::string alignment_fff_str =
+    //        m_appcfg->get("arrange", "alignment_fff");
+
+    //    std::string alignment_fff_seqp_str =
+    //        m_appcfg->get("arrange", "alignment_fff_seq_pring");
+
+    //    std::string alignment_sla_str =
+    //        m_appcfg->get("arrange", "alignment_sla");
+
+    // Override default alignment and save save/load it to a temporary slot "alignment_xl"
+    std::string alignment_xl_str =
+        m_appcfg->get("arrange", "alignment_xl");
+
+    std::string geom_handling_str =
+        m_appcfg->get("arrange", "geometry_handling");
+
+    std::string strategy_str =
+        m_appcfg->get("arrange", "arrange_strategy");
+
+    if (!dist_fff_str.empty())
+        m_settings_fff.vals.d_obj = string_to_float_decimal_point(dist_fff_str);
+
+    if (!dist_bed_fff_str.empty())
+        m_settings_fff.vals.d_bed = string_to_float_decimal_point(dist_bed_fff_str);
+
+    if (!dist_fff_seq_print_str.empty())
+        m_settings_fff_seq.vals.d_obj = string_to_float_decimal_point(dist_fff_seq_print_str);
+
+    if (!dist_bed_fff_seq_print_str.empty())
+        m_settings_fff_seq.vals.d_bed = string_to_float_decimal_point(dist_bed_fff_seq_print_str);
+
+    if (!dist_sla_str.empty())
+        m_settings_sla.vals.d_obj = string_to_float_decimal_point(dist_sla_str);
+
+    if (!dist_bed_sla_str.empty())
+        m_settings_sla.vals.d_bed = string_to_float_decimal_point(dist_bed_sla_str);
+
+    if (!en_rot_fff_str.empty())
+        m_settings_fff.vals.rotations = (en_rot_fff_str == "1" || en_rot_fff_str == "yes");
+
+    if (!en_rot_fff_seqp_str.empty())
+        m_settings_fff_seq.vals.rotations = (en_rot_fff_seqp_str == "1" || en_rot_fff_seqp_str == "yes");
+
+    if (!en_rot_sla_str.empty())
+        m_settings_sla.vals.rotations = (en_rot_sla_str == "1" || en_rot_sla_str == "yes");
+
+    //    if (!alignment_sla_str.empty())
+    //        m_arrange_settings_sla.alignment = std::stoi(alignment_sla_str);
+
+    //    if (!alignment_fff_str.empty())
+    //        m_arrange_settings_fff.alignment = std::stoi(alignment_fff_str);
+
+    //    if (!alignment_fff_seqp_str.empty())
+    //        m_arrange_settings_fff_seq_print.alignment = std::stoi(alignment_fff_seqp_str);
+
+    // Override default alignment and save save/load it to a temporary slot "alignment_xl"
+    ArrangeSettingsView::XLPivots arr_alignment = ArrangeSettingsView::xlpFrontLeft;
+    if (!alignment_xl_str.empty()) {
+        int align_val = std::stoi(alignment_xl_str);
+
+        if (align_val >= 0 && align_val < ArrangeSettingsView::xlpCount)
+            arr_alignment =
+                static_cast<ArrangeSettingsView::XLPivots>(align_val);
+    }
+
+    m_settings_sla.vals.xl_align = arr_alignment ;
+    m_settings_fff.vals.xl_align = arr_alignment ;
+    m_settings_fff_seq.vals.xl_align = arr_alignment ;
+
+    ArrangeSettingsView::GeometryHandling geom_handl = arr2::ArrangeSettingsView::ghConvex;
+    if (!geom_handling_str.empty()) {
+        int gh = std::stoi(geom_handling_str);
+        if(gh >= 0 && gh < ArrangeSettingsView::GeometryHandling::ghCount)
+            geom_handl = static_cast<ArrangeSettingsView::GeometryHandling>(gh);
+    }
+
+    m_settings_sla.vals.geom_handling = geom_handl;
+    m_settings_fff.vals.geom_handling = geom_handl;
+    m_settings_fff_seq.vals.geom_handling = geom_handl;
+
+    ArrangeSettingsView::ArrangeStrategy arr_strategy = arr2::ArrangeSettingsView::asAuto;
+    if (!strategy_str.empty()) {
+        int strateg = std::stoi(strategy_str);
+        if(strateg >= 0 && strateg < ArrangeSettingsView::ArrangeStrategy::asCount)
+            arr_strategy = static_cast<ArrangeSettingsView::ArrangeStrategy>(strateg);
+    }
+
+    m_settings_sla.vals.arr_strategy = arr_strategy;
+    m_settings_fff.vals.arr_strategy = arr_strategy;
+    m_settings_fff_seq.vals.arr_strategy = arr_strategy;
+}
+
+void ArrangeSettingsDb_AppCfg::distance_from_obj_range(float &min,
+                                                       float &max) const
+{
+    min = get_slot(this).dobj_range.minval;
+    max = get_slot(this).dobj_range.maxval;
+}
+
+void ArrangeSettingsDb_AppCfg::distance_from_bed_range(float &min,
+                                                       float &max) const
+{
+    min = get_slot(this).dbed_range.minval;
+    max = get_slot(this).dbed_range.maxval;
+}
+
+arr2::ArrangeSettingsDb& ArrangeSettingsDb_AppCfg::set_distance_from_objects(float v)
+{
+    Slot &slot = get_slot(this);
+    slot.vals.d_obj = v;
+    m_appcfg->set("arrange", "min_object_distance" + slot.postfix,
+                  float_to_string_decimal_point(v));
+
+    return *this;
+}
+
+arr2::ArrangeSettingsDb& ArrangeSettingsDb_AppCfg::set_distance_from_bed(float v)
+{
+    Slot &slot = get_slot(this);
+    slot.vals.d_bed = v;
+    m_appcfg->set("arrange", "min_bed_distance" + slot.postfix,
+                  float_to_string_decimal_point(v));
+
+    return *this;
+}
+
+arr2::ArrangeSettingsDb& ArrangeSettingsDb_AppCfg::set_rotation_enabled(bool v)
+{
+    Slot &slot = get_slot(this);
+    slot.vals.rotations = v;
+    m_appcfg->set("arrange", "enable_rotation" + slot.postfix, v ? "1" : "0");
+
+    return *this;
+}
+
+arr2::ArrangeSettingsDb& ArrangeSettingsDb_AppCfg::set_xl_alignment(XLPivots v)
+{
+    m_settings_fff.vals.xl_align = v;
+    m_appcfg->set("arrange", "alignment_xl", std::to_string(v));
+
+    return *this;
+}
+
+arr2::ArrangeSettingsDb& ArrangeSettingsDb_AppCfg::set_geometry_handling(GeometryHandling v)
+{
+    m_settings_fff.vals.geom_handling = v;
+    m_appcfg->set("arrange", "geometry_handling", std::to_string(v));
+
+    return *this;
+}
+
+arr2::ArrangeSettingsDb& ArrangeSettingsDb_AppCfg::set_arrange_strategy(ArrangeStrategy v)
+{
+    m_settings_fff.vals.arr_strategy = v;
+    m_appcfg->set("arrange", "arrange_strategy", std::to_string(v));
+
+    return *this;
+}
+
+} // namespace Slic3r

src/libslic3r/Arrange/ArrangeSettingsDb_AppCfg.hpp

@@ -0,0 +1,91 @@
+#ifndef ARRANGESETTINGSDB_APPCFG_HPP
+#define ARRANGESETTINGSDB_APPCFG_HPP
+
+#include "ArrangeSettingsView.hpp"
+#include "libslic3r/AppConfig.hpp"
+#include "libslic3r/PrintConfig.hpp"
+
+namespace Slic3r {
+
+class ArrangeSettingsDb_AppCfg: public arr2::ArrangeSettingsDb
+{
+public:
+    enum Slots { slotFFF, slotFFFSeqPrint, slotSLA };
+
+private:
+    AppConfig *m_appcfg;
+    Slots m_current_slot = slotFFF;
+
+    struct FloatRange { float minval = 0.f, maxval = 100.f; };
+    struct Slot
+    {
+        Values      vals;
+        Values      defaults;
+        FloatRange  dobj_range, dbed_range;
+        std::string postfix;
+    };
+
+    // Settings and their defaults are stored separately for fff,
+    // sla and fff sequential mode
+    Slot m_settings_fff, m_settings_fff_seq, m_settings_sla;
+
+    template<class Self>
+    static auto & get_slot(Self *self, Slots slot) {
+        switch(slot) {
+        case slotFFF: return self->m_settings_fff;
+        case slotFFFSeqPrint: return self->m_settings_fff_seq;
+        case slotSLA: return self->m_settings_sla;
+        }
+
+        return self->m_settings_fff;
+    }
+
+    template<class Self> static auto &get_slot(Self *self)
+    {
+        return get_slot(self, self->m_current_slot);
+    }
+
+    template<class Self>
+    static auto& get_ref(Self *self) { return get_slot(self).vals; }
+
+public:
+    explicit ArrangeSettingsDb_AppCfg(AppConfig *appcfg);
+
+    float get_distance_from_objects() const override { return get_ref(this).d_obj; }
+    float get_distance_from_bed() const  override { return get_ref(this).d_bed; }
+    bool  is_rotation_enabled() const override { return get_ref(this).rotations; }
+
+    XLPivots get_xl_alignment() const override { return m_settings_fff.vals.xl_align; }
+    GeometryHandling get_geometry_handling() const override { return m_settings_fff.vals.geom_handling; }
+    ArrangeStrategy get_arrange_strategy() const override { return m_settings_fff.vals.arr_strategy; }
+
+    void distance_from_obj_range(float &min, float &max) const override;
+    void distance_from_bed_range(float &min, float &max) const override;
+
+    ArrangeSettingsDb& set_distance_from_objects(float v) override;
+    ArrangeSettingsDb& set_distance_from_bed(float v) override;
+    ArrangeSettingsDb& set_rotation_enabled(bool v) override;
+
+    ArrangeSettingsDb& set_xl_alignment(XLPivots v) override;
+    ArrangeSettingsDb& set_geometry_handling(GeometryHandling v) override;
+    ArrangeSettingsDb& set_arrange_strategy(ArrangeStrategy v) override;
+
+    Values get_defaults() const override { return get_slot(this).defaults; }
+
+    void set_active_slot(Slots slot) noexcept { m_current_slot = slot; }
+    void set_distance_from_obj_range(Slots slot, float min, float max)
+    {
+        get_slot(this, slot).dobj_range = FloatRange{min, max};
+    }
+
+    void set_distance_from_bed_range(Slots slot, float min, float max)
+    {
+        get_slot(this, slot).dbed_range = FloatRange{min, max};
+    }
+
+    Values &get_defaults(Slots slot) { return get_slot(this, slot).defaults; }
+};
+
+} // namespace Slic3r
+
+#endif // ARRANGESETTINGSDB_APPCFG_HPP

src/libslic3r/Arrange/ArrangeSettingsView.hpp

@@ -0,0 +1,118 @@
+#ifndef ARRANGESETTINGSVIEW_HPP
+#define ARRANGESETTINGSVIEW_HPP
+
+namespace Slic3r { namespace arr2 {
+
+class ArrangeSettingsView
+{
+public:
+    enum GeometryHandling { ghConvex, ghBalanced, ghAdvanced, ghCount };
+    enum ArrangeStrategy { asAuto, asPullToCenter, asCount };
+    enum XLPivots {
+        xlpCenter,
+        xlpRearLeft,
+        xlpFrontLeft,
+        xlpFrontRight,
+        xlpRearRight,
+        xlpRandom,
+        xlpCount
+    };
+
+    virtual ~ArrangeSettingsView() = default;
+
+    virtual float get_distance_from_objects() const = 0;
+    virtual float get_distance_from_bed() const     = 0;
+    virtual bool  is_rotation_enabled() const       = 0;
+
+    virtual XLPivots         get_xl_alignment() const      = 0;
+    virtual GeometryHandling get_geometry_handling() const = 0;
+    virtual ArrangeStrategy  get_arrange_strategy() const  = 0;
+};
+
+class ArrangeSettingsDb: public ArrangeSettingsView
+{
+public:
+
+    virtual void distance_from_obj_range(float &min, float &max) const = 0;
+    virtual void distance_from_bed_range(float &min, float &max) const = 0;
+
+    virtual ArrangeSettingsDb& set_distance_from_objects(float v) = 0;
+    virtual ArrangeSettingsDb& set_distance_from_bed(float v) = 0;
+    virtual ArrangeSettingsDb& set_rotation_enabled(bool v) = 0;
+
+    virtual ArrangeSettingsDb& set_xl_alignment(XLPivots v) = 0;
+    virtual ArrangeSettingsDb& set_geometry_handling(GeometryHandling v) = 0;
+    virtual ArrangeSettingsDb& set_arrange_strategy(ArrangeStrategy v) = 0;
+
+    struct Values {
+        float d_obj = 6.f, d_bed = 0.f;
+        bool rotations = false;
+        XLPivots xl_align = XLPivots::xlpFrontLeft;
+        GeometryHandling geom_handling = GeometryHandling::ghConvex;
+        ArrangeStrategy  arr_strategy = ArrangeStrategy::asAuto;
+
+        Values() = default;
+        Values(const ArrangeSettingsView &sv)
+        {
+            d_bed = sv.get_distance_from_bed();
+            d_obj = sv.get_distance_from_objects();
+            arr_strategy = sv.get_arrange_strategy();
+            geom_handling = sv.get_geometry_handling();
+            rotations = sv.is_rotation_enabled();
+            xl_align = sv.get_xl_alignment();
+        }
+    };
+
+    virtual Values get_defaults() const { return {}; }
+
+    ArrangeSettingsDb& set_from(const ArrangeSettingsView &sv)
+    {
+        set_distance_from_bed(sv.get_distance_from_bed());
+        set_distance_from_objects(sv.get_distance_from_objects());
+        set_arrange_strategy(sv.get_arrange_strategy());
+        set_geometry_handling(sv.get_geometry_handling());
+        set_rotation_enabled(sv.is_rotation_enabled());
+        set_xl_alignment(sv.get_xl_alignment());
+
+        return *this;
+    }
+};
+
+class ArrangeSettings: public Slic3r::arr2::ArrangeSettingsDb
+{
+    ArrangeSettingsDb::Values m_v = {};
+
+public:
+    explicit ArrangeSettings(
+        const ArrangeSettingsDb::Values &v = {})
+        : m_v{v}
+    {}
+
+    explicit ArrangeSettings(const ArrangeSettingsView &v)
+        : m_v{v}
+    {}
+
+    float get_distance_from_objects() const override { return m_v.d_obj; }
+    float get_distance_from_bed() const override { return m_v.d_bed; }
+    bool  is_rotation_enabled() const override { return m_v.rotations; }
+    XLPivots get_xl_alignment() const override { return m_v.xl_align; }
+    GeometryHandling get_geometry_handling() const override { return m_v.geom_handling; }
+    ArrangeStrategy get_arrange_strategy() const override { return m_v.arr_strategy; }
+
+    void distance_from_obj_range(float &min, float &max) const override { min = 0.f; max = 100.f; }
+    void distance_from_bed_range(float &min, float &max) const override { min = 0.f; max = 100.f; }
+
+    ArrangeSettings& set_distance_from_objects(float v) override { m_v.d_obj = v; return *this; }
+    ArrangeSettings& set_distance_from_bed(float v) override { m_v.d_bed = v; return *this; }
+    ArrangeSettings& set_rotation_enabled(bool v) override { m_v.rotations = v; return *this; }
+    ArrangeSettings& set_xl_alignment(XLPivots v) override { m_v.xl_align = v; return *this; }
+    ArrangeSettings& set_geometry_handling(GeometryHandling v) override { m_v.geom_handling = v; return *this; }
+    ArrangeSettings& set_arrange_strategy(ArrangeStrategy v) override { m_v.arr_strategy = v; return *this; }
+
+    auto & values() const { return m_v; }
+    auto & values() { return m_v; }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGESETTINGSVIEW_HPP

src/libslic3r/Arrange/Core/ArrangeBase.hpp

@@ -0,0 +1,294 @@
+#ifndef ARRANGEBASE_HPP
+#define ARRANGEBASE_HPP
+
+#include <iterator>
+#include <type_traits>
+
+#include "ArrangeItemTraits.hpp"
+#include "PackingContext.hpp"
+
+#include "libslic3r/Point.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+namespace detail_is_const_it {
+
+template<class It, class En = void>
+struct IsConstIt_ { static constexpr bool value = false; };
+
+template<class It>
+using iterator_category_t = typename std::iterator_traits<It>::iterator_category;
+
+template<class It>
+using iterator_reference_t = typename std::iterator_traits<It>::reference;
+
+template<class It>
+struct IsConstIt_ <It, std::enable_if_t<std::is_class_v<iterator_category_t<It>>> >
+{
+    static constexpr bool value =
+        std::is_const_v<std::remove_reference_t<iterator_reference_t<It>>>;
+};
+
+} // namespace detail_is_const_it
+
+template<class It>
+static constexpr bool IsConstIterator = detail_is_const_it::IsConstIt_<It>::value;
+
+template<class It>
+constexpr bool is_const_iterator(const It &it) noexcept { return IsConstIterator<It>; }
+
+// The pack() function will use tag dispatching, based on the given strategy
+// object that is used as its first argument.
+
+// This tag is derived for a packing strategy as default, and will be used
+// to cast a compile error.
+struct UnimplementedPacking {};
+
+// PackStrategyTag_ needs to be specialized for any valid packing strategy class
+template<class PackStrategy> struct PackStrategyTag_ {
+    using Tag = UnimplementedPacking;
+};
+
+// Helper metafunc to derive packing strategy tag from a strategy object.
+template<class Strategy>
+using PackStrategyTag =
+    typename PackStrategyTag_<remove_cvref_t<Strategy>>::Tag;
+
+
+template<class PackStrategy, class En = void> struct PackStrategyTraits_ {
+    template<class ArrItem> using Context = DefaultPackingContext<ArrItem>;
+
+    template<class ArrItem, class Bed>
+    static Context<ArrItem> create_context(PackStrategy &ps,
+                                           const Bed &bed,
+                                           int bed_index)
+    {
+        return {};
+    }
+};
+
+template<class PS> using PackStrategyTraits = PackStrategyTraits_<StripCVRef<PS>>;
+
+template<class PS, class ArrItem>
+using PackStrategyContext =
+    typename PackStrategyTraits<PS>::template Context<StripCVRef<ArrItem>>;
+
+template<class ArrItem, class PackStrategy, class Bed>
+PackStrategyContext<PackStrategy, ArrItem> create_context(PackStrategy &&ps,
+                                                          const Bed &bed,
+                                                          int bed_index)
+{
+    return PackStrategyTraits<PackStrategy>::template create_context<
+        StripCVRef<ArrItem>>(ps, bed, bed_index);
+}
+
+// Function to pack one item into a bed.
+// strategy parameter holds clue to what packing strategy to use. This function
+//          needs to be overloaded for the strategy tag belonging to the given
+//          strategy.
+// 'bed' parameter is the type of bed into which the new item should be packed.
+//       See beds.hpp for valid bed classes.
+// 'item' parameter is the item to be packed. After succesful arrangement
+//        (see return value) the item will have it's translation and rotation
+//        set correctly. If the function returns false, the translation and
+//        rotation of the input item might be changed to arbitrary values.
+// 'fixed_items' paramter holds a range of ArrItem type objects that are already
+//               on the bed and need to be avoided by the newly packed item.
+// 'remaining_items' is a range of ArrItem type objects that are intended to be
+//                   packed in the future. This information can be leveradged by
+//                   the packing strategy to make more intelligent placement
+//                   decisions for the input item.
+template<class Strategy, class Bed, class ArrItem, class RemIt>
+bool pack(Strategy &&strategy,
+          const Bed &bed,
+          ArrItem &item,
+          const PackStrategyContext<Strategy, ArrItem> &context,
+          const Range<RemIt> &remaining_items)
+{
+    static_assert(IsConstIterator<RemIt>, "Remaining item iterator is not const!");
+
+    // Dispatch:
+    return pack(std::forward<Strategy>(strategy), bed, item, context,
+                remaining_items, PackStrategyTag<Strategy>{});
+}
+
+// Overload without fixed items:
+template<class Strategy, class Bed, class ArrItem>
+bool pack(Strategy &&strategy, const Bed &bed, ArrItem &item)
+{
+    std::vector<ArrItem> dummy;
+    auto context = create_context<ArrItem>(strategy, bed, PhysicalBedId);
+    return pack(std::forward<Strategy>(strategy), bed, item, context,
+                crange(dummy));
+}
+
+// Overload when strategy is unkown, yields compile error:
+template<class Strategy, class Bed, class ArrItem, class RemIt>
+bool pack(Strategy &&strategy,
+          const Bed &bed,
+          ArrItem &item,
+          const PackStrategyContext<Strategy, ArrItem> &context,
+          const Range<RemIt> &remaining_items,
+          const UnimplementedPacking &)
+{
+    static_assert(always_false<Strategy>::value,
+                  "Packing unimplemented for this placement strategy");
+
+    return false;
+}
+
+// Helper function to remove unpackable items from the input container.
+template<class PackStrategy, class Container, class Bed, class StopCond>
+void remove_unpackable_items(PackStrategy  &&ps,
+                             Container      &c,
+                             const Bed      &bed,
+                             const StopCond &stopcond)
+{
+    // Safety test: try to pack each item into an empty bed. If it fails
+    // then it should be removed from the list
+    auto it = c.begin();
+    while (it != c.end() && !stopcond()) {
+        StripCVRef<decltype(*it)> &itm = *it;
+        auto cpy{itm};
+
+        if (!pack(ps, bed, cpy)) {
+            set_bed_index(itm, Unarranged);
+            it = c.erase(it);
+        } else
+            it++;
+    }
+}
+
+// arrange() function will use tag dispatching based on the selection strategy
+// given as its first argument.
+
+// This tag is derived for a selection strategy as default, and will be used
+// to cast a compile error.
+struct UnimplementedSelection {};
+
+// SelStrategyTag_ needs to be specialized for any valid selection strategy class
+template<class SelStrategy> struct SelStrategyTag_ {
+    using Tag = UnimplementedSelection;
+};
+
+// Helper metafunc to derive the selection strategy tag from a strategy object.
+template<class Strategy>
+using SelStrategyTag = typename SelStrategyTag_<remove_cvref_t<Strategy>>::Tag;
+
+// Main function to start the arrangement. Takes a selection and a packing
+// strategy object as the first two parameters. An implementation
+// (function overload) must exist for this function that takes the coresponding
+// selection strategy tag belonging to the given selstrategy argument.
+//
+// items parameter is a range of arrange items to arrange.
+// fixed parameter is a range of arrange items that have fixed position and will
+//                 not move during the arrangement but need to be avoided by the
+//                 moving items.
+// bed parameter is the type of bed into which the items need to fit.
+template<class It,
+         class ConstIt,
+         class TBed,
+         class SelectionStrategy,
+         class PackStrategy>
+void arrange(SelectionStrategy &&selstrategy,
+             PackStrategy &&packingstrategy,
+             const Range<It> &items,
+             const Range<ConstIt> &fixed,
+             const TBed &bed)
+{
+    static_assert(IsConstIterator<ConstIt>, "Fixed item iterator is not const!");
+
+    // Dispatch:
+    arrange(std::forward<SelectionStrategy>(selstrategy),
+            std::forward<PackStrategy>(packingstrategy), items, fixed, bed,
+            SelStrategyTag<SelectionStrategy>{});
+}
+
+template<class It, class TBed, class SelectionStrategy, class PackStrategy>
+void arrange(SelectionStrategy &&selstrategy,
+             PackStrategy &&packingstrategy,
+             const Range<It> &items,
+             const TBed &bed)
+{
+    std::vector<typename std::iterator_traits<It>::value_type> dummy;
+    arrange(std::forward<SelectionStrategy>(selstrategy),
+            std::forward<PackStrategy>(packingstrategy), items, crange(dummy),
+            bed);
+}
+
+// Overload for unimplemented selection strategy, yields compile error:
+template<class It,
+         class ConstIt,
+         class TBed,
+         class SelectionStrategy,
+         class PackStrategy>
+void arrange(SelectionStrategy &&selstrategy,
+             PackStrategy &&packingstrategy,
+             const Range<It> &items,
+             const Range<ConstIt> &fixed,
+             const TBed &bed,
+             const UnimplementedSelection &)
+{
+    static_assert(always_false<SelectionStrategy>::value,
+                  "Arrange unimplemented for this selection strategy");
+}
+
+template<class It>
+std::vector<int> get_bed_indices(const Range<It> &items)
+{
+    auto bed_indices = reserve_vector<int>(items.size());
+
+    for (auto &itm : items)
+        bed_indices.emplace_back(get_bed_index(itm));
+
+    std::sort(bed_indices.begin(), bed_indices.end());
+    auto endit = std::unique(bed_indices.begin(), bed_indices.end());
+
+    bed_indices.erase(endit, bed_indices.end());
+
+    return bed_indices;
+}
+
+template<class It, class CIt>
+std::vector<int> get_bed_indices(const Range<It> &items, const Range<CIt> &fixed)
+{
+    std::vector<int> ret;
+
+    auto iitems = get_bed_indices(items);
+    auto ifixed = get_bed_indices(fixed);
+    ret.reserve(std::max(iitems.size(), ifixed.size()));
+    std::set_union(iitems.begin(), iitems.end(),
+                   ifixed.begin(), ifixed.end(),
+                   std::back_inserter(ret));
+
+    return ret;
+}
+
+template<class It>
+size_t get_bed_count(const Range<It> &items)
+{
+    return get_bed_indices(items).size();
+}
+
+template<class It> int get_max_bed_index(const Range<It> &items)
+{
+    auto it = std::max_element(items.begin(),
+                               items.end(),
+                               [](auto &i1, auto &i2) {
+                                   return get_bed_index(i1) < get_bed_index(i2);
+                               });
+
+    int ret = Unarranged;
+    if (it != items.end())
+        ret = get_bed_index(*it);
+
+    return ret;
+}
+
+struct DefaultStopCondition {
+    constexpr bool operator()() const noexcept { return false; }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGEBASE_HPP

src/libslic3r/Arrange/Core/ArrangeFirstFit.hpp

@@ -0,0 +1,165 @@
+#ifndef ARRANGEFIRSTFIT_HPP
+#define ARRANGEFIRSTFIT_HPP
+
+#include <iterator>
+#include <map>
+
+#include <libslic3r/Arrange/Core/ArrangeBase.hpp>
+
+namespace Slic3r { namespace arr2 { namespace firstfit {
+
+struct SelectionTag {};
+
+// Can be specialized by Items
+template<class ArrItem, class En = void>
+struct ItemArrangedVisitor {
+    template<class Bed, class PIt, class RIt>
+    static void on_arranged(ArrItem &itm,
+                            const Bed &bed,
+                            const Range<PIt> &packed_items,
+                            const Range<RIt> &remaining_items)
+    {}
+};
+
+// Use the the visitor baked into the ArrItem type by default
+struct DefaultOnArrangedFn {
+    template<class ArrItem, class Bed, class PIt, class RIt>
+    void operator()(ArrItem &itm,
+                    const Bed &bed,
+                    const Range<PIt> &packed,
+                    const Range<RIt> &remaining)
+    {
+        ItemArrangedVisitor<StripCVRef<ArrItem>>::on_arranged(itm, bed, packed,
+                                                              remaining);
+    }
+};
+
+struct DefaultItemCompareFn {
+    template<class ArrItem>
+    bool operator() (const ArrItem &ia, const ArrItem &ib)
+    {
+        return get_priority(ia) > get_priority(ib);
+    }
+};
+
+template<class CompareFn  = DefaultItemCompareFn,
+         class OnArrangedFn = DefaultOnArrangedFn,
+         class StopCondition = DefaultStopCondition>
+struct SelectionStrategy
+{
+    CompareFn  cmpfn;
+    OnArrangedFn on_arranged_fn;
+    StopCondition cancel_fn;
+
+    SelectionStrategy(CompareFn cmp = {},
+             OnArrangedFn on_arranged = {},
+             StopCondition stopcond = {})
+        : cmpfn{cmp},
+          on_arranged_fn{std::move(on_arranged)},
+          cancel_fn{std::move(stopcond)}
+    {}
+};
+
+} // namespace firstfit
+
+template<class... Args> struct SelStrategyTag_<firstfit::SelectionStrategy<Args...>> {
+    using Tag = firstfit::SelectionTag;
+};
+
+template<class It,
+         class ConstIt,
+         class TBed,
+         class SelStrategy,
+         class PackStrategy>
+void arrange(
+    SelStrategy &&sel,
+    PackStrategy &&ps,
+    const Range<It> &items,
+    const Range<ConstIt> &fixed,
+    const TBed &bed,
+    const firstfit::SelectionTag &)
+{
+    using ArrItem = typename std::iterator_traits<It>::value_type;
+    using ArrItemRef = std::reference_wrapper<ArrItem>;
+
+    auto sorted_items = reserve_vector<ArrItemRef>(items.size());
+
+    for (auto &itm : items) {
+        set_bed_index(itm, Unarranged);
+        sorted_items.emplace_back(itm);
+    }
+
+    using Context = PackStrategyContext<PackStrategy, ArrItem>;
+
+    std::map<int, Context> bed_contexts;
+    auto get_or_init_context = [&ps, &bed, &bed_contexts](int bedidx) -> Context& {
+        auto ctx_it = bed_contexts.find(bedidx);
+        if (ctx_it == bed_contexts.end()) {
+            auto res = bed_contexts.emplace(
+                bedidx, create_context<ArrItem>(ps, bed, bedidx));
+
+            assert(res.second);
+
+            ctx_it = res.first;
+        }
+
+        return ctx_it->second;
+    };
+
+    for (auto &itm : fixed) {
+        auto bedidx = get_bed_index(itm);
+        if (bedidx >= 0) {
+            Context &ctx = get_or_init_context(bedidx);
+            add_fixed_item(ctx, itm);
+        }
+    }
+
+    if constexpr (!std::is_null_pointer_v<decltype(sel.cmpfn)>) {
+        std::stable_sort(sorted_items.begin(), sorted_items.end(), sel.cmpfn);
+    }
+
+    auto is_cancelled = [&sel]() {
+        return sel.cancel_fn();
+    };
+
+    remove_unpackable_items(ps, sorted_items, bed, [&is_cancelled]() {
+        return is_cancelled();
+    });
+
+    auto it = sorted_items.begin();
+
+    using SConstIt = typename std::vector<ArrItemRef>::const_iterator;
+
+    while (it != sorted_items.end() && !is_cancelled()) {
+        bool was_packed = false;
+        int bedidx = 0;
+        while (!was_packed && !is_cancelled()) {
+            for (; !was_packed && !is_cancelled(); bedidx++) {
+                set_bed_index(*it, bedidx);
+
+                auto remaining = Range{std::next(static_cast<SConstIt>(it)),
+                                       sorted_items.cend()};
+
+                Context &ctx = get_or_init_context(bedidx);
+
+                was_packed = pack(ps, bed, *it, ctx, remaining);
+
+                if(was_packed) {
+                    add_packed_item(ctx, *it);
+
+                    auto packed_range = Range{sorted_items.cbegin(),
+                                              static_cast<SConstIt>(it)};
+
+                    sel.on_arranged_fn(*it, bed, packed_range, remaining);
+                } else {
+                    set_bed_index(*it, Unarranged);
+                }
+            }
+        }
+        ++it;
+    }
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGEFIRSTFIT_HPP

src/libslic3r/Arrange/Core/ArrangeItemTraits.hpp

@@ -0,0 +1,113 @@
+#ifndef ARRANGE_ITEM_TRAITS_HPP
+#define ARRANGE_ITEM_TRAITS_HPP
+
+#include <libslic3r/Point.hpp>
+
+namespace Slic3r { namespace arr2 {
+
+// A logical bed representing an object not being arranged. Either the arrange
+// has not yet successfully run on this ArrangePolygon or it could not fit the
+// object due to overly large size or invalid geometry.
+const constexpr int Unarranged = -1;
+
+const constexpr int PhysicalBedId = 0;
+
+// Basic interface of an arrange item. This struct can be specialized for any
+// type that is arrangeable.
+template<class ArrItem, class En = void> struct ArrangeItemTraits_ {
+    static Vec2crd get_translation(const ArrItem &ap)
+    {
+        return ap.get_translation();
+    }
+
+    static double get_rotation(const ArrItem &ap)
+    {
+        return ap.get_rotation();
+    }
+
+    static int get_bed_index(const ArrItem &ap) { return ap.get_bed_index(); }
+
+    static int get_priority(const ArrItem &ap) { return ap.get_priority(); }
+
+    // Setters:
+
+    static void set_translation(ArrItem &ap, const Vec2crd &v)
+    {
+        ap.set_translation(v);
+    }
+
+    static void set_rotation(ArrItem &ap, double v) { ap.set_rotation(v); }
+
+    static void set_bed_index(ArrItem &ap, int v) { ap.set_bed_index(v); }
+};
+
+template<class T> using ArrangeItemTraits = ArrangeItemTraits_<StripCVRef<T>>;
+
+// Getters:
+
+template<class T> Vec2crd get_translation(const T &itm)
+{
+    return ArrangeItemTraits<T>::get_translation(itm);
+}
+
+template<class T> double get_rotation(const T &itm)
+{
+    return ArrangeItemTraits<T>::get_rotation(itm);
+}
+
+template<class T> int get_bed_index(const T &itm)
+{
+    return ArrangeItemTraits<T>::get_bed_index(itm);
+}
+
+template<class T> int get_priority(const T &itm)
+{
+    return ArrangeItemTraits<T>::get_priority(itm);
+}
+
+// Setters:
+
+template<class T> void set_translation(T &itm, const Vec2crd &v)
+{
+    ArrangeItemTraits<T>::set_translation(itm, v);
+}
+
+template<class T> void set_rotation(T &itm, double v)
+{
+    ArrangeItemTraits<T>::set_rotation(itm, v);
+}
+
+template<class T> void set_bed_index(T &itm, int v)
+{
+    ArrangeItemTraits<T>::set_bed_index(itm, v);
+}
+
+// Helper functions for arrange items
+template<class ArrItem> bool is_arranged(const ArrItem &ap)
+{
+    return get_bed_index(ap) > Unarranged;
+}
+
+template<class ArrItem> bool is_fixed(const ArrItem &ap)
+{
+    return get_bed_index(ap) >= PhysicalBedId;
+}
+
+template<class ArrItem> bool is_on_physical_bed(const ArrItem &ap)
+{
+    return get_bed_index(ap) == PhysicalBedId;
+}
+
+template<class ArrItem> void translate(ArrItem &ap, const Vec2crd &t)
+{
+    set_translation(ap, get_translation(ap) + t);
+}
+
+template<class ArrItem> void rotate(ArrItem &ap, double rads)
+{
+    set_rotation(ap, get_rotation(ap) + rads);
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGE_ITEM_HPP

src/libslic3r/Arrange/Core/Beds.cpp

@@ -0,0 +1,129 @@
+#include "Beds.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+BoundingBox bounding_box(const InfiniteBed &bed)
+{
+    BoundingBox ret;
+    using C = coord_t;
+
+    // It is important for Mx and My to be strictly less than half of the
+    // range of type C. width(), height() and area() will not overflow this way.
+    C Mx = C((std::numeric_limits<C>::lowest() + 2 * bed.center.x()) / 4.01);
+    C My = C((std::numeric_limits<C>::lowest() + 2 * bed.center.y()) / 4.01);
+
+    ret.max = bed.center - Point{Mx, My};
+    ret.min = bed.center + Point{Mx, My};
+
+    return ret;
+}
+
+Polygon to_rectangle(const BoundingBox &bb)
+{
+    Polygon ret;
+    ret.points = {
+        bb.min,
+        Point{bb.max.x(), bb.min.y()},
+        bb.max,
+        Point{bb.min.x(), bb.max.y()}
+    };
+
+    return ret;
+}
+
+Polygon approximate_circle_with_polygon(const arr2::CircleBed &bed, int nedges)
+{
+    Polygon ret;
+
+    double angle_incr = (2 * M_PI) / nedges; // Angle increment for each edge
+    double angle = 0; // Starting angle
+
+    // Loop to generate vertices for each edge
+    for (int i = 0; i < nedges; i++) {
+        // Calculate coordinates of the vertices using trigonometry
+        auto x = bed.center().x() + static_cast<coord_t>(bed.radius() * std::cos(angle));
+        auto y = bed.center().y() + static_cast<coord_t>(bed.radius() * std::sin(angle));
+
+        // Add vertex to the vector
+        ret.points.emplace_back(x, y);
+
+        // Update the angle for the next iteration
+        angle += angle_incr;
+    }
+
+    return ret;
+}
+
+inline coord_t width(const BoundingBox &box)
+{
+    return box.max.x() - box.min.x();
+}
+inline coord_t height(const BoundingBox &box)
+{
+    return box.max.y() - box.min.y();
+}
+inline double poly_area(const Points &pts)
+{
+    return std::abs(Polygon::area(pts));
+}
+inline double distance_to(const Point &p1, const Point &p2)
+{
+    double dx = p2.x() - p1.x();
+    double dy = p2.y() - p1.y();
+    return std::sqrt(dx * dx + dy * dy);
+}
+
+static CircleBed to_circle(const Point &center, const Points &points)
+{
+    std::vector<double> vertex_distances;
+    double              avg_dist = 0;
+
+    for (const Point &pt : points) {
+        double distance = distance_to(center, pt);
+        vertex_distances.push_back(distance);
+        avg_dist += distance;
+    }
+
+    avg_dist /= vertex_distances.size();
+
+    CircleBed ret(center, avg_dist);
+    for (auto el : vertex_distances) {
+        if (std::abs(el - avg_dist) > 10 * SCALED_EPSILON) {
+            ret = {};
+            break;
+        }
+    }
+
+    return ret;
+}
+
+template<class Fn> auto call_with_bed(const Points &bed, Fn &&fn)
+{
+    if (bed.empty())
+        return fn(InfiniteBed{});
+    else if (bed.size() == 1)
+        return fn(InfiniteBed{bed.front()});
+    else {
+        auto      bb    = BoundingBox(bed);
+        CircleBed circ  = to_circle(bb.center(), bed);
+        auto      parea = poly_area(bed);
+
+        if ((1.0 - parea / area(bb)) < 1e-3) {
+            return fn(RectangleBed{bb});
+        } else if (!std::isnan(circ.radius()) && (1.0 - parea / area(circ)) < 1e-2)
+            return fn(circ);
+        else
+            return fn(IrregularBed{{ExPolygon(bed)}});
+    }
+}
+
+ArrangeBed to_arrange_bed(const Points &bedpts)
+{
+    ArrangeBed ret;
+
+    call_with_bed(bedpts, [&](const auto &bed) { ret = bed; });
+
+    return ret;
+}
+
+}} // namespace Slic3r::arr2

src/libslic3r/Arrange/Core/Beds.hpp

@@ -0,0 +1,191 @@
+#ifndef BEDS_HPP
+#define BEDS_HPP
+
+#include <numeric>
+
+#include <libslic3r/Point.hpp>
+#include <libslic3r/ExPolygon.hpp>
+#include <libslic3r/BoundingBox.hpp>
+#include <libslic3r/ClipperUtils.hpp>
+
+#include <boost/variant.hpp>
+
+namespace Slic3r { namespace arr2 {
+
+// Bed types to be used with arrangement. Most generic bed is a simple polygon
+// with holes, but other special bed types are also valid, like a bed without
+// boundaries, or a special case of a rectangular or circular bed which leaves
+// a lot of room for optimizations.
+
+// Representing an unbounded bed.
+struct InfiniteBed {
+    Point center;
+    explicit InfiniteBed(const Point &p = {0, 0}): center{p} {}
+};
+
+BoundingBox bounding_box(const InfiniteBed &bed);
+
+inline InfiniteBed offset(const InfiniteBed &bed, coord_t) { return bed; }
+
+struct RectangleBed {
+    BoundingBox bb;
+
+    explicit RectangleBed(const BoundingBox &bedbb) : bb{bedbb} {}
+    explicit RectangleBed(coord_t w, coord_t h, Point c = {0, 0}):
+        bb{{c.x() - w / 2, c.y() - h / 2}, {c.x() + w / 2, c.y() + h / 2}}
+    {}
+
+    coord_t width() const { return bb.size().x(); }
+    coord_t height() const { return bb.size().y(); }
+};
+
+inline BoundingBox bounding_box(const RectangleBed &bed) { return bed.bb; }
+inline RectangleBed offset(RectangleBed bed, coord_t v)
+{
+    bed.bb.offset(v);
+    return bed;
+}
+
+Polygon to_rectangle(const BoundingBox &bb);
+
+inline Polygon to_rectangle(const RectangleBed &bed)
+{
+    return to_rectangle(bed.bb);
+}
+
+class CircleBed {
+    Point  m_center;
+    double m_radius;
+
+public:
+    CircleBed(): m_center(0, 0), m_radius(NaNd) {}
+    explicit CircleBed(const Point& c, double r)
+        : m_center(c)
+        , m_radius(r)
+    {}
+
+    double radius() const { return m_radius; }
+    const Point& center() const { return m_center; }
+};
+
+// Function to approximate a circle with a convex polygon
+Polygon approximate_circle_with_polygon(const CircleBed &bed, int nedges = 24);
+
+inline BoundingBox bounding_box(const CircleBed &bed)
+{
+    auto r = static_cast<coord_t>(std::round(bed.radius()));
+    Point R{r, r};
+
+    return {bed.center() - R, bed.center() + R};
+}
+inline CircleBed offset(const CircleBed &bed, coord_t v)
+{
+    return CircleBed{bed.center(), bed.radius() + v};
+}
+
+struct IrregularBed { ExPolygons poly; };
+inline BoundingBox bounding_box(const IrregularBed &bed)
+{
+    return get_extents(bed.poly);
+}
+
+inline IrregularBed offset(IrregularBed bed, coord_t v)
+{
+    bed.poly = offset_ex(bed.poly, v);
+    return bed;
+}
+
+using ArrangeBed =
+    boost::variant<InfiniteBed, RectangleBed, CircleBed, IrregularBed>;
+
+inline BoundingBox bounding_box(const ArrangeBed &bed)
+{
+    BoundingBox ret;
+    auto visitor = [&ret](const auto &b) { ret = bounding_box(b); };
+    boost::apply_visitor(visitor, bed);
+
+    return ret;
+}
+
+inline ArrangeBed offset(ArrangeBed bed, coord_t v)
+{
+    auto visitor = [v](auto &b) { b = offset(b, v); };
+    boost::apply_visitor(visitor, bed);
+
+    return bed;
+}
+
+inline double area(const BoundingBox &bb)
+{
+    auto bbsz = bb.size();
+    return double(bbsz.x()) * bbsz.y();
+}
+
+inline double area(const RectangleBed &bed)
+{
+    auto bbsz = bed.bb.size();
+    return double(bbsz.x()) * bbsz.y();
+}
+
+inline double area(const InfiniteBed &bed)
+{
+    return std::numeric_limits<double>::infinity();
+}
+
+inline double area(const IrregularBed &bed)
+{
+    return std::accumulate(bed.poly.begin(), bed.poly.end(), 0.,
+                           [](double s, auto &p) { return s + p.area(); });
+}
+
+inline double area(const CircleBed &bed)
+{
+    return bed.radius() * bed.radius() * PI;
+}
+
+inline double area(const ArrangeBed &bed)
+{
+    double ret = 0.;
+    auto visitor = [&ret](auto &b) { ret = area(b); };
+    boost::apply_visitor(visitor, bed);
+
+    return ret;
+}
+
+inline ExPolygons to_expolygons(const InfiniteBed &bed)
+{
+    return {ExPolygon{to_rectangle(RectangleBed{scaled(1000.), scaled(1000.)})}};
+}
+
+inline ExPolygons to_expolygons(const RectangleBed &bed)
+{
+    return {ExPolygon{to_rectangle(bed)}};
+}
+
+inline ExPolygons to_expolygons(const CircleBed &bed)
+{
+    return {ExPolygon{approximate_circle_with_polygon(bed)}};
+}
+
+inline ExPolygons to_expolygons(const IrregularBed &bed) { return bed.poly; }
+
+inline ExPolygons to_expolygons(const ArrangeBed &bed)
+{
+    ExPolygons ret;
+    auto visitor = [&ret](const auto &b) { ret = to_expolygons(b); };
+    boost::apply_visitor(visitor, bed);
+
+    return ret;
+}
+
+ArrangeBed to_arrange_bed(const Points &bedpts);
+
+} // namespace arr2
+
+inline BoundingBox &bounding_box(BoundingBox &bb) { return bb; }
+inline const BoundingBox &bounding_box(const BoundingBox &bb) { return bb; }
+inline BoundingBox bounding_box(const Polygon &p) { return get_extents(p); }
+
+} // namespace Slic3r
+
+#endif // BEDS_HPP

src/libslic3r/Arrange/Core/DataStoreTraits.hpp

@@ -0,0 +1,78 @@
+#ifndef DATASTORETRAITS_HPP
+#define DATASTORETRAITS_HPP
+
+#include <string_view>
+
+#include "libslic3r/libslic3r.h"
+
+namespace Slic3r { namespace arr2 {
+
+// Some items can be containers of arbitrary data stored under string keys.
+template<class ArrItem, class En = void> struct DataStoreTraits_
+{
+    static constexpr bool Implemented = false;
+
+    template<class T> static const T *get(const ArrItem &, const std::string &key)
+    {
+        return nullptr;
+    }
+
+    // Same as above just not const.
+    template<class T> static T *get(ArrItem &, const std::string &key)
+    {
+        return nullptr;
+    }
+
+    static bool has_key(const ArrItem &itm, const std::string &key)
+    {
+        return false;
+    }
+};
+
+template<class ArrItem, class En = void> struct WritableDataStoreTraits_
+{
+    static constexpr bool Implemented = false;
+
+    template<class T> static void set(ArrItem &, const std::string &key, T &&data)
+    {
+    }
+};
+
+template<class T> using DataStoreTraits = DataStoreTraits_<StripCVRef<T>>;
+template<class T> constexpr bool IsDataStore = DataStoreTraits<StripCVRef<T>>::Implemented;
+template<class T, class TT = T> using DataStoreOnly = std::enable_if_t<IsDataStore<T>, TT>;
+
+template<class T, class ArrItem>
+const T *get_data(const ArrItem &itm, const std::string &key)
+{
+    return DataStoreTraits<ArrItem>::template get<T>(itm, key);
+}
+
+template<class ArrItem>
+bool has_key(const ArrItem &itm, const std::string &key)
+{
+    return DataStoreTraits<ArrItem>::has_key(itm, key);
+}
+
+template<class T, class ArrItem>
+T *get_data(ArrItem &itm, const std::string &key)
+{
+    return DataStoreTraits<ArrItem>::template get<T>(itm, key);
+}
+
+template<class T> using WritableDataStoreTraits = WritableDataStoreTraits_<StripCVRef<T>>;
+template<class T> constexpr bool IsWritableDataStore = WritableDataStoreTraits<StripCVRef<T>>::Implemented;
+template<class T, class TT = T> using WritableDataStoreOnly = std::enable_if_t<IsWritableDataStore<T>, TT>;
+
+template<class T, class ArrItem>
+void set_data(ArrItem &itm, const std::string &key, T &&data)
+{
+    WritableDataStoreTraits<ArrItem>::template set(itm, key, std::forward<T>(data));
+}
+
+template<class T> constexpr bool IsReadWritableDataStore = IsDataStore<T> && IsWritableDataStore<T>;
+template<class T, class TT = T> using ReadWritableDataStoreOnly = std::enable_if_t<IsReadWritableDataStore<T>, TT>;
+
+}} // namespace Slic3r::arr2
+
+#endif // DATASTORETRAITS_HPP

src/libslic3r/Arrange/Core/NFP/CircularEdgeIterator.hpp

@@ -0,0 +1,110 @@
+#ifndef CIRCULAR_EDGEITERATOR_HPP
+#define CIRCULAR_EDGEITERATOR_HPP
+
+#include <libslic3r/Polygon.hpp>
+#include <libslic3r/Line.hpp>
+
+namespace Slic3r {
+
+// Circular iterator over a polygon yielding individual edges as Line objects
+// if flip_lines is true, the orientation of each line is flipped (not the
+// direction of traversal)
+template<bool flip_lines = false>
+class CircularEdgeIterator_ {
+    const Polygon *m_poly = nullptr;
+    size_t m_i = 0;
+    size_t m_c = 0; // counting how many times the iterator has circled over
+
+public:
+
+    // i: vertex position of first line's starting vertex
+    // poly: target polygon
+    CircularEdgeIterator_(size_t i, const Polygon &poly)
+        : m_poly{&poly}
+        , m_i{!poly.empty() ? i % poly.size() : 0}
+        , m_c{!poly.empty() ? i / poly.size() : 0}
+    {}
+
+    explicit CircularEdgeIterator_ (const Polygon &poly)
+        : CircularEdgeIterator_(0, poly) {}
+
+    using iterator_category = std::forward_iterator_tag;
+    using difference_type   = std::ptrdiff_t;
+    using value_type        = Line;
+    using pointer           = Line*;
+    using reference         = Line&;
+
+    CircularEdgeIterator_ & operator++()
+    {
+        assert (m_poly);
+        ++m_i;
+        if (m_i == m_poly->size()) { // faster than modulo (?)
+            m_i = 0;
+            ++m_c;
+        }
+
+        return *this;
+    }
+
+    CircularEdgeIterator_ operator++(int)
+    {
+        auto cpy = *this; ++(*this); return cpy;
+    }
+
+    Line operator*() const
+    {
+        size_t nx = m_i == m_poly->size() - 1 ? 0 : m_i + 1;
+        Line ret;
+        if constexpr (flip_lines)
+            ret = Line((*m_poly)[nx], (*m_poly)[m_i]);
+        else
+            ret = Line((*m_poly)[m_i], (*m_poly)[nx]);
+
+        return ret;
+    }
+
+    Line operator->() const { return *(*this); }
+
+    bool operator==(const CircularEdgeIterator_& other) const
+    {
+        return m_i == other.m_i && m_c == other.m_c;
+    }
+
+    bool operator!=(const CircularEdgeIterator_& other) const
+    {
+        return !(*this == other);
+    }
+
+    CircularEdgeIterator_& operator +=(size_t dist)
+    {
+        m_i = (m_i + dist) % m_poly->size();
+        m_c = (m_i + (m_c * m_poly->size()) + dist) / m_poly->size();
+
+        return *this;
+    }
+
+    CircularEdgeIterator_ operator +(size_t dist)
+    {
+        auto cpy = *this;
+        cpy += dist;
+
+        return cpy;
+    }
+};
+
+using CircularEdgeIterator = CircularEdgeIterator_<>;
+using CircularReverseEdgeIterator = CircularEdgeIterator_<true>;
+
+inline Range<CircularEdgeIterator> line_range(const Polygon &poly)
+{
+    return Range{CircularEdgeIterator{0, poly}, CircularEdgeIterator{poly.size(), poly}};
+}
+
+inline Range<CircularReverseEdgeIterator> line_range_flp(const Polygon &poly)
+{
+    return Range{CircularReverseEdgeIterator{0, poly}, CircularReverseEdgeIterator{poly.size(), poly}};
+}
+
+} // namespace Slic3r
+
+#endif // CIRCULAR_EDGEITERATOR_HPP

src/libslic3r/Arrange/Core/NFP/EdgeCache.cpp

@@ -0,0 +1,92 @@
+#include "EdgeCache.hpp"
+#include "CircularEdgeIterator.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+void EdgeCache::create_cache(const ExPolygon &sh)
+{
+    m_contour.distances.reserve(sh.contour.size());
+    m_holes.reserve(sh.holes.size());
+
+    m_contour.poly = &sh.contour;
+
+    fill_distances(sh.contour, m_contour.distances);
+
+    for (const Polygon &hole : sh.holes) {
+        auto &hc = m_holes.emplace_back();
+        hc.poly = &hole;
+        fill_distances(hole, hc.distances);
+    }
+}
+
+Vec2crd EdgeCache::coords(const ContourCache &cache, double distance) const
+{
+    assert(cache.poly);
+    return arr2::coords(*cache.poly, cache.distances, distance);
+}
+
+void EdgeCache::sample_contour(double accuracy, std::vector<ContourLocation> &samples)
+{
+    const auto N = m_contour.distances.size();
+    const auto S = stride(N, accuracy);
+
+    samples.reserve(N / S + 1);
+    for(size_t i = 0; i < N; i += S) {
+        samples.emplace_back(
+            ContourLocation{0, m_contour.distances[i] / m_contour.distances.back()});
+    }
+
+    for (size_t hidx = 1; hidx <= m_holes.size(); ++hidx) {
+        auto& hc = m_holes[hidx - 1];
+
+        const auto NH = hc.distances.size();
+        const auto SH = stride(NH, accuracy);
+        samples.reserve(samples.size() + NH / SH + 1);
+        for (size_t i = 0; i < NH; i += SH) {
+            samples.emplace_back(
+                ContourLocation{hidx, hc.distances[i] / hc.distances.back()});
+        }
+    }
+}
+
+Vec2crd coords(const Polygon &poly, const std::vector<double> &distances, double distance)
+{
+    assert(poly.size() > 1 && distance >= .0 && distance <= 1.0);
+
+    // distance is from 0.0 to 1.0, we scale it up to the full length of
+    // the circumference
+    double d = distance * distances.back();
+
+    // Magic: we find the right edge in log time
+    auto it = std::lower_bound(distances.begin(), distances.end(), d);
+
+    assert(it != distances.end());
+
+    auto idx  = it - distances.begin(); // get the index of the edge
+    auto &pts = poly.points;
+    auto edge = idx == long(pts.size() - 1) ? Line(pts.back(), pts.front()) :
+                                              Line(pts[idx], pts[idx + 1]);
+
+    // Get the remaining distance on the target edge
+    auto ed = d - (idx > 0 ? *std::prev(it) : 0 );
+
+    double t = ed / edge.length();
+    Vec2d n {double(edge.b.x()) - edge.a.x(), double(edge.b.y()) - edge.a.y()};
+    Vec2crd ret = (edge.a.cast<double>() + t * n).cast<coord_t>();
+
+    return ret;
+}
+
+void fill_distances(const Polygon &poly, std::vector<double> &distances)
+{
+    distances.reserve(poly.size());
+
+    double dist = 0.;
+    auto lrange = line_range(poly);
+    for (const Line &l : lrange) {
+        dist += l.length();
+        distances.emplace_back(dist);
+    }
+}
+
+}} // namespace Slic3r::arr2

src/libslic3r/Arrange/Core/NFP/EdgeCache.hpp

@@ -0,0 +1,70 @@
+#ifndef EDGECACHE_HPP
+#define EDGECACHE_HPP
+
+#include <vector>
+
+#include <libslic3r/ExPolygon.hpp>
+
+namespace Slic3r { namespace arr2 {
+
+// Position on the circumference of an ExPolygon.
+// countour_id:  0th is contour, 1..N are holes
+// dist: position given as a floating point number within <0., 1.>
+struct ContourLocation { size_t contour_id; double dist; };
+
+void fill_distances(const Polygon &poly, std::vector<double> &distances);
+
+Vec2crd coords(const Polygon &poly, const std::vector<double>& distances, double distance);
+
+// A class for getting a point on the circumference of the polygon (in log time)
+//
+// This is a transformation of the provided polygon to be able to pinpoint
+// locations on the circumference. The optimizer will pass a floating point
+// value e.g. within <0,1> and we have to transform this value quickly into a
+// coordinate on the circumference. By definition 0 should yield the first
+// vertex and 1.0 would be the last (which should coincide with first).
+//
+// We also have to make this work for the holes of the captured polygon.
+class EdgeCache {
+    struct ContourCache {
+        const Polygon *poly;
+        std::vector<double> distances;
+    } m_contour;
+
+    std::vector<ContourCache> m_holes;
+
+    void create_cache(const ExPolygon& sh);
+
+    Vec2crd coords(const ContourCache& cache, double distance) const;
+
+public:
+
+    explicit EdgeCache(const ExPolygon *sh)
+    {
+        create_cache(*sh);
+    }
+
+    // Given coeff for accuracy <0., 1.>, return the number of vertices to skip
+    // when fetching corners.
+    static inline size_t stride(const size_t N, double accuracy)
+    {
+        return static_cast<coord_t>(
+            std::round(N / std::pow(N, std::pow(accuracy, 1./3.)))
+            );
+    }
+
+    void sample_contour(double accuracy, std::vector<ContourLocation> &samples);
+
+    Vec2crd coords(const ContourLocation &loc) const
+    {
+        assert(loc.contour_id <= m_holes.size());
+
+        return loc.contour_id > 0 ?
+                   coords(m_holes[loc.contour_id - 1], loc.dist) :
+                   coords(m_contour, loc.dist);
+    }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // EDGECACHE_HPP

src/libslic3r/Arrange/Core/NFP/Kernels/CompactifyKernel.hpp

@@ -0,0 +1,61 @@
+#ifndef COMPACTIFYKERNEL_HPP
+#define COMPACTIFYKERNEL_HPP
+
+#include <numeric>
+
+#include "libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/Beds.hpp"
+
+#include <libslic3r/Geometry/ConvexHull.hpp>
+#include <libslic3r/ClipperUtils.hpp>
+
+#include "KernelUtils.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+struct CompactifyKernel {
+    ExPolygons merged_pile;
+
+    template<class ArrItem>
+    double placement_fitness(const ArrItem &itm, const Vec2crd &transl) const
+    {
+        auto pile = merged_pile;
+
+        ExPolygons itm_tr = to_expolygons(envelope_outline(itm));
+        for (auto &p : itm_tr)
+            p.translate(transl);
+
+        append(pile, std::move(itm_tr));
+
+        pile = union_ex(pile);
+
+        Polygon chull = Geometry::convex_hull(pile);
+
+        return -(chull.area());
+    }
+
+    template<class ArrItem, class Bed, class Context, class RemIt>
+    bool on_start_packing(ArrItem &itm,
+                          const Bed &bed,
+                          const Context &packing_context,
+                          const Range<RemIt> & /*remaining_items*/)
+    {
+        bool ret = find_initial_position(itm, bounding_box(bed).center(), bed,
+                                         packing_context);
+
+        merged_pile.clear();
+        for (const auto &gitm : all_items_range(packing_context)) {
+            append(merged_pile, to_expolygons(fixed_outline(gitm)));
+        }
+        merged_pile = union_ex(merged_pile);
+
+        return ret;
+    }
+
+    template<class ArrItem>
+    bool on_item_packed(ArrItem &itm) { return true; }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // COMPACTIFYKERNEL_HPP

src/libslic3r/Arrange/Core/NFP/Kernels/GravityKernel.hpp

@@ -0,0 +1,58 @@
+#ifndef GRAVITYKERNEL_HPP
+#define GRAVITYKERNEL_HPP
+
+#include "libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/Beds.hpp"
+
+#include "KernelUtils.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+struct GravityKernel {
+    std::optional<Vec2crd> sink;
+    std::optional<Vec2crd> item_sink;
+    Vec2d active_sink;
+
+    GravityKernel(Vec2crd gravity_center) : sink{gravity_center} {}
+    GravityKernel() = default;
+
+    template<class ArrItem>
+    double placement_fitness(const ArrItem &itm, const Vec2crd &transl) const
+    {
+        Vec2d center = unscaled(envelope_centroid(itm));
+
+        center += unscaled(transl);
+
+        return - (center - active_sink).squaredNorm();
+    }
+
+    template<class ArrItem, class Bed, class Ctx, class RemIt>
+    bool on_start_packing(ArrItem &itm,
+                          const Bed &bed,
+                          const Ctx &packing_context,
+                          const Range<RemIt> & /*remaining_items*/)
+    {
+        bool ret = false;
+
+        item_sink = get_gravity_sink(itm);
+
+        if (!sink) {
+            sink = bounding_box(bed).center();
+        }
+
+        if (item_sink)
+            active_sink = unscaled(*item_sink);
+        else
+            active_sink = unscaled(*sink);
+
+        ret = find_initial_position(itm, scaled(active_sink), bed, packing_context);
+
+        return ret;
+    }
+
+    template<class ArrItem> bool on_item_packed(ArrItem &itm) { return true; }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // GRAVITYKERNEL_HPP

src/libslic3r/Arrange/Core/NFP/Kernels/KernelTraits.hpp

@@ -0,0 +1,57 @@
+#ifndef KERNELTRAITS_HPP
+#define KERNELTRAITS_HPP
+
+#include "libslic3r/Arrange/Core/ArrangeItemTraits.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+// An arrangement kernel that specifies the object function to the arrangement
+// optimizer and additional callback functions to be able to track the state
+// of the arranged pile during arrangement.
+template<class Kernel, class En = void> struct KernelTraits_
+{
+    // Has to return a score value marking the quality of the arrangement. The
+    // higher this value is, the better a particular placement of the item is.
+    // parameter transl is the translation needed for the item to be moved to
+    // the candidate position.
+    // To discard the item, return NaN as score for every translation.
+    template<class ArrItem>
+    static double placement_fitness(const Kernel  &k,
+                                    const ArrItem &itm,
+                                    const Vec2crd &transl)
+    {
+        return k.placement_fitness(itm, transl);
+    }
+
+    // Called whenever a new item is about to be processed by the optimizer.
+    // The current state of the arrangement can be saved by the kernel: the
+    // already placed items and the remaining items that need to fit into a
+    // particular bed.
+    // Returns true if the item is can be packed immediately, false if it
+    // should be processed further. This way, a kernel have the power to
+    // choose an initial position for the item that is not on the NFP.
+    template<class ArrItem, class Bed, class Ctx, class RemIt>
+    static bool on_start_packing(Kernel &k,
+                                 ArrItem &itm,
+                                 const Bed &bed,
+                                 const Ctx &packing_context,
+                                 const Range<RemIt> &remaining_items)
+    {
+        return k.on_start_packing(itm, bed, packing_context, remaining_items);
+    }
+
+    // Called when an item has been succesfully packed. itm should have the
+    // final translation and rotation already set.
+    // Can return false to discard the item after the optimization.
+    template<class ArrItem>
+    static bool on_item_packed(Kernel &k, ArrItem &itm)
+    {
+        return k.on_item_packed(itm);
+    }
+};
+
+template<class K> using KernelTraits = KernelTraits_<StripCVRef<K>>;
+
+}} // namespace Slic3r::arr2
+
+#endif // KERNELTRAITS_HPP

src/libslic3r/Arrange/Core/NFP/Kernels/KernelUtils.hpp

@@ -0,0 +1,75 @@
+#ifndef ARRANGEKERNELUTILS_HPP
+#define ARRANGEKERNELUTILS_HPP
+
+#include <type_traits>
+
+#include "libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/Beds.hpp"
+#include "libslic3r/Arrange/Core/DataStoreTraits.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+template<class Itm, class Bed, class Context>
+bool find_initial_position(Itm &itm,
+                           const Vec2crd &sink,
+                           const Bed &bed,
+                           const Context &packing_context)
+{
+    bool ret = false;
+
+    if constexpr (std::is_convertible_v<Bed, RectangleBed> ||
+                  std::is_convertible_v<Bed, InfiniteBed> ||
+                  std::is_convertible_v<Bed, CircleBed>)
+    {
+        if (all_items_range(packing_context).empty()) {
+            auto rotations = allowed_rotations(itm);
+            auto chull     = envelope_convex_hull(itm);
+
+            for (double rot : rotations) {
+                auto chullcpy = chull;
+                chullcpy.rotate(rot);
+                auto bbitm = bounding_box(chullcpy);
+
+                Vec2crd cb = sink;
+                Vec2crd ci = bbitm.center();
+
+                Vec2crd d = cb - ci;
+                bbitm.translate(d);
+
+                if (bounding_box(bed).contains(bbitm)) {
+                    rotate(itm, rot);
+                    translate(itm, d);
+                    ret = true;
+                    break;
+                }
+            }
+        }
+    }
+
+    return ret;
+}
+
+template<class ArrItem> std::optional<Vec2crd> get_gravity_sink(const ArrItem &itm)
+{
+    constexpr const char * SinkKey = "sink";
+
+    std::optional<Vec2crd> ret;
+
+    auto ptr = get_data<Vec2crd>(itm, SinkKey);
+
+    if (ptr)
+        ret = *ptr;
+
+    return ret;
+}
+
+template<class ArrItem> bool is_wipe_tower(const ArrItem &itm)
+{
+    constexpr const char * Key = "is_wipe_tower";
+
+    return has_key(itm, Key);
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGEKERNELUTILS_HPP

src/libslic3r/Arrange/Core/NFP/Kernels/RectangleOverfitKernelWrapper.hpp

@@ -0,0 +1,94 @@
+#ifndef RECTANGLEOVERFITKERNELWRAPPER_HPP
+#define RECTANGLEOVERFITKERNELWRAPPER_HPP
+
+#include "KernelTraits.hpp"
+
+#include "libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/Beds.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+// This is a kernel wrapper that will apply a penality to the object function
+// if the result cannot fit into the given rectangular bounds. This can be used
+// to arrange into rectangular boundaries without calculating the IFP of the
+// rectangle bed. Note that after the arrangement, what is garanteed is that
+// the resulting pile will fit into the rectangular boundaries, but it will not
+// be within the given rectangle. The items need to be moved afterwards manually.
+// Use RectangeOverfitPackingStrategy to automate this post process step.
+template<class Kernel>
+struct RectangleOverfitKernelWrapper {
+    Kernel &k;
+    BoundingBox binbb;
+    BoundingBox pilebb;
+
+    RectangleOverfitKernelWrapper(Kernel &kern, const BoundingBox &limits)
+        : k{kern}
+          , binbb{limits}
+    {}
+
+    double overfit(const BoundingBox &itmbb) const
+    {
+        auto fullbb = pilebb;
+        fullbb.merge(itmbb);
+        auto fullbbsz = fullbb.size();
+        auto binbbsz  = binbb.size();
+
+        auto wdiff = fullbbsz.x() - binbbsz.x() - SCALED_EPSILON;
+        auto hdiff = fullbbsz.y() - binbbsz.y() - SCALED_EPSILON;
+        double miss = .0;
+        if (wdiff > 0)
+            miss += double(wdiff);
+        if (hdiff > 0)
+            miss += double(hdiff);
+
+        miss = miss > 0? miss : 0;
+
+        return miss;
+    }
+
+    template<class ArrItem>
+    double placement_fitness(const ArrItem &item, const Vec2crd &transl) const
+    {
+        double score = KernelTraits<Kernel>::placement_fitness(k, item, transl);
+
+        auto itmbb = envelope_bounding_box(item);
+        itmbb.translate(transl);
+        double miss = overfit(itmbb);
+        score -= miss * miss;
+
+        return score;
+    }
+
+    template<class ArrItem, class Bed, class Ctx, class RemIt>
+    bool on_start_packing(ArrItem &itm,
+                          const Bed &bed,
+                          const Ctx &packing_context,
+                          const Range<RemIt> &remaining_items)
+    {
+        pilebb = BoundingBox{};
+
+        for (auto &fitm : all_items_range(packing_context))
+            pilebb.merge(fixed_bounding_box(fitm));
+
+        return KernelTraits<Kernel>::on_start_packing(k, itm, RectangleBed{binbb},
+                                                      packing_context,
+                                                      remaining_items);
+    }
+
+    template<class ArrItem>
+    bool on_item_packed(ArrItem &itm)
+    {
+        bool ret = KernelTraits<Kernel>::on_item_packed(k, itm);
+
+        double miss = overfit(envelope_bounding_box(itm));
+
+        if (miss > 0.)
+            ret = false;
+
+        return ret;
+    }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // RECTANGLEOVERFITKERNELWRAPPER_H

src/libslic3r/Arrange/Core/NFP/Kernels/SVGDebugOutputKernelWrapper.hpp

@@ -0,0 +1,96 @@
+#ifndef SVGDEBUGOUTPUTKERNELWRAPPER_HPP
+#define SVGDEBUGOUTPUTKERNELWRAPPER_HPP
+
+#include <memory>
+
+#include "KernelTraits.hpp"
+
+#include "libslic3r/Arrange/Core/PackingContext.hpp"
+#include "libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/Beds.hpp"
+
+#include <libslic3r/SVG.hpp>
+
+namespace Slic3r { namespace arr2 {
+
+template<class Kernel>
+struct SVGDebugOutputKernelWrapper {
+    Kernel &k;
+    std::unique_ptr<Slic3r::SVG> svg;
+    BoundingBox drawbounds;
+
+    template<class... Args>
+    SVGDebugOutputKernelWrapper(const BoundingBox &bounds, Kernel &kern)
+        : k{kern}, drawbounds{bounds}
+    {}
+
+    template<class ArrItem, class Bed, class Context, class RemIt>
+    bool on_start_packing(ArrItem &itm,
+                          const Bed &bed,
+                          const Context &packing_context,
+                          const Range<RemIt> &rem)
+    {
+        using namespace Slic3r;
+
+        bool ret = KernelTraits<Kernel>::on_start_packing(k, itm, bed,
+                                                          packing_context,
+                                                          rem);
+
+        if (arr2::get_bed_index(itm) < 0)
+            return ret;
+
+        svg.reset();
+        auto bounds = drawbounds;
+        auto fixed = all_items_range(packing_context);
+        svg = std::make_unique<SVG>(std::string("arrange_bed") +
+                                        std::to_string(
+                                            arr2::get_bed_index(itm)) +
+                                        "_" + std::to_string(fixed.size()) +
+                                        ".svg",
+                                    bounds, 0, false);
+
+        svg->draw(ExPolygon{arr2::to_rectangle(drawbounds)}, "blue", .2f);
+
+        auto nfp = calculate_nfp(itm, packing_context, bed);
+        svg->draw_outline(nfp);
+        svg->draw(nfp, "green", 0.2f);
+
+        for (const auto &fixeditm : fixed) {
+            ExPolygons fixeditm_outline = to_expolygons(fixed_outline(fixeditm));
+            svg->draw_outline(fixeditm_outline);
+            svg->draw(fixeditm_outline, "yellow", 0.5f);
+        }
+
+        return ret;
+    }
+
+    template<class ArrItem>
+    double placement_fitness(const ArrItem &item, const Vec2crd &transl) const
+    {
+        return KernelTraits<Kernel>::placement_fitness(k, item, transl);
+    }
+
+    template<class ArrItem>
+    bool on_item_packed(ArrItem &itm)
+    {
+        using namespace Slic3r;
+        using namespace Slic3r::arr2;
+
+        bool ret = KernelTraits<Kernel>::on_item_packed(k, itm);
+
+        if (svg) {
+            ExPolygons itm_outline = to_expolygons(fixed_outline(itm));
+
+            svg->draw_outline(itm_outline);
+            svg->draw(itm_outline, "grey");
+
+            svg->Close();
+        }
+
+        return ret;
+    }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // SVGDEBUGOUTPUTKERNELWRAPPER_HPP

src/libslic3r/Arrange/Core/NFP/Kernels/TMArrangeKernel.hpp

@@ -0,0 +1,270 @@
+#ifndef TMARRANGEKERNEL_HPP
+#define TMARRANGEKERNEL_HPP
+
+#include "libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/Beds.hpp"
+
+#include "KernelUtils.hpp"
+
+#include <boost/geometry/index/rtree.hpp>
+#include <libslic3r/BoostAdapter.hpp>
+
+namespace Slic3r { namespace arr2 {
+
+// Summon the spatial indexing facilities from boost
+namespace bgi = boost::geometry::index;
+using SpatElement = std::pair<BoundingBox, unsigned>;
+using SpatIndex = bgi::rtree<SpatElement, bgi::rstar<16, 4> >;
+
+class TMArrangeKernel {
+    SpatIndex   m_rtree;        // spatial index for the normal (bigger) objects
+    SpatIndex   m_smallsrtree;  // spatial index for only the smaller items
+    BoundingBox m_pilebb;
+    double      m_bin_area = NaNd;
+    double      m_norm;
+    size_t      m_rem_cnt = 0;
+    size_t      m_item_cnt = 0;
+
+
+    struct ItemStats { double area = 0.; BoundingBox bb; };
+    std::vector<ItemStats> m_itemstats;
+
+    // A coefficient used in separating bigger items and smaller items.
+    static constexpr double BigItemTreshold = 0.02;
+
+    template<class T> ArithmeticOnly<T, double> norm(T val) const
+    {
+        return double(val) / m_norm;
+    }
+
+    // Treat big items (compared to the print bed) differently
+    bool is_big(double a) const { return a / m_bin_area > BigItemTreshold; }
+
+protected:
+    std::optional<Point> sink;
+    std::optional<Point> item_sink;
+    Point                active_sink;
+
+    const BoundingBox & pilebb() const { return m_pilebb; }
+
+public:
+    TMArrangeKernel() = default;
+    TMArrangeKernel(Vec2crd gravity_center, size_t itm_cnt, double bedarea = NaNd)
+        : sink{gravity_center}
+        , m_bin_area(bedarea)
+        , m_item_cnt{itm_cnt}
+    {}
+
+    TMArrangeKernel(size_t itm_cnt, double bedarea = NaNd)
+        : m_bin_area(bedarea), m_item_cnt{itm_cnt}
+    {}
+
+    template<class ArrItem>
+    double placement_fitness(const ArrItem &item, const Vec2crd &transl) const
+    {
+        // Candidate item bounding box
+        auto ibb = envelope_bounding_box(item);
+        ibb.translate(transl);
+        auto itmcntr = envelope_centroid(item);
+        itmcntr += transl;
+
+        // Calculate the full bounding box of the pile with the candidate item
+        auto fullbb = m_pilebb;
+        fullbb.merge(ibb);
+
+        // The bounding box of the big items (they will accumulate in the center
+        // of the pile
+        BoundingBox bigbb;
+        if(m_rtree.empty()) {
+            bigbb = fullbb;
+        }
+        else {
+            auto boostbb = m_rtree.bounds();
+            boost::geometry::convert(boostbb, bigbb);
+        }
+
+        // Will hold the resulting score
+        double score = 0;
+
+        // Density is the pack density: how big is the arranged pile
+        double density = 0;
+
+        // Distinction of cases for the arrangement scene
+        enum e_cases {
+            // This branch is for big items in a mixed (big and small) scene
+            // OR for all items in a small-only scene.
+            BIG_ITEM,
+
+            // This branch is for the last big item in a mixed scene
+            LAST_BIG_ITEM,
+
+            // For small items in a mixed scene.
+            SMALL_ITEM,
+
+            WIPE_TOWER,
+        } compute_case;
+
+        bool is_wt = is_wipe_tower(item);
+        bool bigitems = is_big(envelope_area(item)) || m_rtree.empty();
+        if (is_wt)
+            compute_case = WIPE_TOWER;
+        else if (bigitems && m_rem_cnt > 0)
+            compute_case = BIG_ITEM;
+        else if (bigitems && m_rem_cnt == 0)
+            compute_case = LAST_BIG_ITEM;
+        else
+            compute_case = SMALL_ITEM;
+
+        switch (compute_case) {
+        case WIPE_TOWER: {
+            score = (unscaled(itmcntr) - unscaled(active_sink)).squaredNorm();
+            break;
+        }
+        case BIG_ITEM: {
+            const Point& minc = ibb.min; // bottom left corner
+            const Point& maxc = ibb.max; // top right corner
+
+            // top left and bottom right corners
+            Point top_left{minc.x(), maxc.y()};
+            Point bottom_right{maxc.x(), minc.y()};
+
+            // Now the distance of the gravity center will be calculated to the
+            // five anchor points and the smallest will be chosen.
+            std::array<double, 5> dists;
+            auto cc = fullbb.center(); // The gravity center
+            dists[0] = (minc - cc).cast<double>().norm();
+            dists[1] = (maxc - cc).cast<double>().norm();
+            dists[2] = (itmcntr - cc).template cast<double>().norm();
+            dists[3] = (top_left - cc).cast<double>().norm();
+            dists[4] = (bottom_right - cc).cast<double>().norm();
+
+            // The smalles distance from the arranged pile center:
+            double dist = norm(*(std::min_element(dists.begin(), dists.end())));
+            double bindist = norm((ibb.center() - active_sink).template cast<double>().norm());
+            dist = 0.8 * dist + 0.2 * bindist;
+
+            // Prepare a variable for the alignment score.
+            // This will indicate: how well is the candidate item
+            // aligned with its neighbors. We will check the alignment
+            // with all neighbors and return the score for the best
+            // alignment. So it is enough for the candidate to be
+            // aligned with only one item.
+            auto alignment_score = 1.0;
+
+            auto query = bgi::intersects(ibb);
+            auto& index = is_big(envelope_area(item)) ? m_rtree : m_smallsrtree;
+
+            // Query the spatial index for the neighbors
+            std::vector<SpatElement> result;
+            result.reserve(index.size());
+
+            index.query(query, std::back_inserter(result));
+
+            // now get the score for the best alignment
+            for(auto& e : result) {
+                auto idx = e.second;
+                const ItemStats& p = m_itemstats[idx];
+                auto parea = p.area;
+                if(std::abs(1.0 - parea / fixed_area(item)) < 1e-6) {
+                    auto bb = p.bb;
+                    bb.merge(ibb);
+                    auto bbarea = area(bb);
+                    auto ascore = 1.0 - (fixed_area(item) + parea) / bbarea;
+
+                    if(ascore < alignment_score)
+                        alignment_score = ascore;
+                }
+            }
+
+            auto fullbbsz = fullbb.size();
+            density = std::sqrt(norm(fullbbsz.x()) * norm(fullbbsz.y()));
+            double R = double(m_rem_cnt) / (m_item_cnt);
+
+            // The final mix of the score is the balance between the
+            // distance from the full pile center, the pack density and
+            // the alignment with the neighbors
+            if (result.empty())
+                score = 0.50 * dist + 0.50 * density;
+            else
+                // Let the density matter more when fewer objects remain
+                score = 0.50 * dist + (1.0 - R) * 0.20 * density +
+                        0.30 * alignment_score;
+
+            break;
+        }
+        case LAST_BIG_ITEM: {
+            score = norm((itmcntr - m_pilebb.center()).template cast<double>().norm());
+            break;
+        }
+        case SMALL_ITEM: {
+            // Here there are the small items that should be placed around the
+            // already processed bigger items.
+            // No need to play around with the anchor points, the center will be
+            // just fine for small items
+            score = norm((itmcntr - bigbb.center()).template cast<double>().norm());
+            break;
+        }
+        }
+
+        return -score;
+    }
+
+    template<class ArrItem, class Bed, class Context, class RemIt>
+    bool on_start_packing(ArrItem &itm,
+                          const Bed &bed,
+                          const Context &packing_context,
+                          const Range<RemIt> &remaining_items)
+    {
+        item_sink = get_gravity_sink(itm);
+
+        if (!sink) {
+            sink = bounding_box(bed).center();
+        }
+
+        if (item_sink)
+            active_sink = *item_sink;
+        else
+            active_sink = *sink;
+
+        auto fixed = all_items_range(packing_context);
+
+        bool ret = find_initial_position(itm, active_sink, bed, packing_context);
+
+        m_rem_cnt = remaining_items.size();
+
+        if (m_item_cnt == 0)
+            m_item_cnt = m_rem_cnt + fixed.size() + 1;
+
+        if (std::isnan(m_bin_area))
+            m_bin_area = area(bed);
+
+        m_norm = std::sqrt(m_bin_area);
+
+        m_itemstats.clear();
+        m_itemstats.reserve(fixed.size());
+        m_rtree.clear();
+        m_smallsrtree.clear();
+        m_pilebb = {};
+        unsigned idx = 0;
+        for (auto &fixitem : fixed) {
+            auto fixitmbb = fixed_bounding_box(fixitem);
+            m_itemstats.emplace_back(ItemStats{fixed_area(fixitem), fixitmbb});
+            m_pilebb.merge(fixitmbb);
+
+            if(is_big(fixed_area(fixitem)))
+                m_rtree.insert({fixitmbb, idx});
+
+            m_smallsrtree.insert({fixitmbb, idx});
+            idx++;
+        }
+
+        return ret;
+    }
+
+    template<class ArrItem>
+    bool on_item_packed(ArrItem &itm) { return true; }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // TMARRANGEKERNEL_HPP

src/libslic3r/Arrange/Core/NFP/NFP.cpp

@@ -0,0 +1,418 @@
+#ifndef NFP_CPP
+#define NFP_CPP
+
+#include "NFP.hpp"
+#include "CircularEdgeIterator.hpp"
+
+#include "NFPConcave_Tesselate.hpp"
+
+#if !defined(_MSC_VER) && defined(__SIZEOF_INT128__) && !defined(__APPLE__)
+namespace Slic3r { using LargeInt = __int128; }
+#else
+#include <boost/multiprecision/integer.hpp>
+namespace Slic3r { using LargeInt = boost::multiprecision::int128_t; }
+#endif
+
+#include <boost/rational.hpp>
+
+namespace Slic3r {
+
+static bool line_cmp(const Line& e1, const Line& e2)
+{
+    using Ratio = boost::rational<LargeInt>;
+
+    const Vec<2, int64_t> ax(1, 0); // Unit vector for the X axis
+
+    Vec<2, int64_t> p1 = (e1.b - e1.a).cast<int64_t>();
+    Vec<2, int64_t> p2 = (e2.b - e2.a).cast<int64_t>();
+
+    // Quadrant mapping array. The quadrant of a vector can be determined
+    // from the dot product of the vector and its perpendicular pair
+    // with the unit vector X axis. The products will carry the values
+    // lcos = dot(p, ax) = l * cos(phi) and
+    // lsin = -dotperp(p, ax) = l * sin(phi) where
+    // l is the length of vector p. From the signs of these values we can
+    // construct an index which has the sign of lcos as MSB and the
+    // sign of lsin as LSB. This index can be used to retrieve the actual
+    // quadrant where vector p resides using the following map:
+    // (+ is 0, - is 1)
+    // cos | sin | decimal | quadrant
+    //  +  |  +  |    0    |    0
+    //  +  |  -  |    1    |    3
+    //  -  |  +  |    2    |    1
+    //  -  |  -  |    3    |    2
+    std::array<int, 4> quadrants {0, 3, 1, 2 };
+
+    std::array<int, 2> q {0, 0}; // Quadrant indices for p1 and p2
+
+    using TDots = std::array<int64_t, 2>;
+    TDots lcos { p1.dot(ax), p2.dot(ax) };
+    TDots lsin { -dotperp(p1, ax), -dotperp(p2, ax) };
+
+    // Construct the quadrant indices for p1 and p2
+    for(size_t i = 0; i < 2; ++i) {
+        if (lcos[i] == 0)
+            q[i] = lsin[i] > 0 ? 1 : 3;
+        else if (lsin[i] == 0)
+            q[i] = lcos[i] > 0 ? 0 : 2;
+        else
+            q[i] = quadrants[((lcos[i] < 0) << 1) + (lsin[i] < 0)];
+    }
+
+    if (q[0] == q[1]) { // only bother if p1 and p2 are in the same quadrant
+        auto lsq1 = p1.squaredNorm();     // squared magnitudes, avoid sqrt
+        auto lsq2 = p2.squaredNorm();     // squared magnitudes, avoid sqrt
+
+        // We will actually compare l^2 * cos^2(phi) which saturates the
+        // cos function. But with the quadrant info we can get the sign back
+        int sign = q[0] == 1 || q[0] == 2 ? -1 : 1;
+
+        // If Ratio is an actual rational type, there is no precision loss
+        auto pcos1 = Ratio(lcos[0]) / lsq1 * sign * lcos[0];
+        auto pcos2 = Ratio(lcos[1]) / lsq2 * sign * lcos[1];
+
+        return q[0] < 2 ? pcos1 > pcos2 : pcos1 < pcos2;
+    }
+
+    // If in different quadrants, compare the quadrant indices only.
+    return q[0] < q[1];
+}
+
+static inline bool vsort(const Vec2crd& v1, const Vec2crd& v2)
+{
+    return v1.y() == v2.y() ? v1.x() < v2.x() : v1.y() < v2.y();
+}
+
+ExPolygons ifp_convex(const arr2::RectangleBed &obed, const Polygon &convexpoly)
+{
+    ExPolygon ret;
+
+    auto sbox = bounding_box(convexpoly);
+    auto sboxsize = sbox.size();
+    coord_t sheight = sboxsize.y();
+    coord_t swidth  = sboxsize.x();
+    Point   sliding_top = reference_vertex(convexpoly);
+    auto    leftOffset   = sliding_top.x() - sbox.min.x();
+    auto    rightOffset  = sliding_top.x() - sbox.max.x();
+    coord_t topOffset    = 0;
+    auto    bottomOffset = sheight;
+
+    auto bedbb = obed.bb;
+//    bedbb.offset(1);
+    auto bedsz = bedbb.size();
+    auto boxWidth  = bedsz.x();
+    auto boxHeight = bedsz.y();
+
+    auto bedMinx = bedbb.min.x();
+    auto bedMiny = bedbb.min.y();
+    auto bedMaxx = bedbb.max.x();
+    auto bedMaxy = bedbb.max.y();
+
+    Polygon innerNfp{ Point{bedMinx + leftOffset, bedMaxy + topOffset},
+                      Point{bedMaxx + rightOffset, bedMaxy + topOffset},
+                      Point{bedMaxx + rightOffset, bedMiny + bottomOffset},
+                      Point{bedMinx + leftOffset, bedMiny + bottomOffset},
+                      Point{bedMinx + leftOffset, bedMaxy + topOffset} };
+
+    if (sheight <= boxHeight && swidth <= boxWidth)
+        ret.contour = std::move(innerNfp);
+
+    return {ret};
+}
+
+Polygon ifp_convex_convex(const Polygon &fixed, const Polygon &movable)
+{
+    auto subnfps = reserve_polygons(fixed.size());
+
+    // For each edge of the bed polygon, determine the nfp of convexpoly and
+    // the zero area polygon formed by the edge. The union of all these sub-nfps
+    // will contain a hole that is the actual ifp.
+    auto lrange = line_range(fixed);
+    for (const Line &l : lrange) { // Older mac compilers generate warnging if line_range is called in-place
+        Polygon fixed = {l.a, l.b};
+        subnfps.emplace_back(nfp_convex_convex_legacy(fixed, movable));
+    }
+
+    // Do the union and then keep only the holes (should be only one or zero, if
+    // the convexpoly cannot fit into the bed)
+    Polygons ifp = union_(subnfps);
+    Polygon ret;
+
+    // find the first hole
+    auto it = std::find_if(ifp.begin(), ifp.end(), [](const Polygon &subifp){
+        return subifp.is_clockwise();
+    });
+
+    if (it != ifp.end()) {
+        ret = std::move(*it);
+        std::reverse(ret.begin(), ret.end());
+    }
+
+    return ret;
+}
+
+ExPolygons ifp_convex(const arr2::CircleBed &bed, const Polygon &convexpoly)
+{
+    Polygon circle = approximate_circle_with_polygon(bed);
+
+    return {ExPolygon{ifp_convex_convex(circle, convexpoly)}};
+}
+
+ExPolygons ifp_convex(const arr2::IrregularBed &bed, const Polygon &convexpoly)
+{
+    auto bb = get_extents(bed.poly);
+    bb.offset(scaled(1.));
+
+    Polygon rect = arr2::to_rectangle(bb);
+
+    ExPolygons blueprint = diff_ex(rect, bed.poly);
+    Polygons ifp;
+    for (const ExPolygon &part : blueprint) {
+        Polygons triangles = Slic3r::convex_decomposition_tess(part);
+        for (const Polygon &tr : triangles) {
+            Polygon subifp = nfp_convex_convex_legacy(tr, convexpoly);
+            ifp.emplace_back(std::move(subifp));
+        }
+    }
+
+    ifp = union_(ifp);
+
+    Polygons ret;
+
+    std::copy_if(ifp.begin(), ifp.end(), std::back_inserter(ret),
+                 [](const Polygon &p) { return p.is_clockwise(); });
+
+    for (Polygon &p : ret)
+        std::reverse(p.begin(), p.end());
+
+    return to_expolygons(ret);
+}
+
+Vec2crd reference_vertex(const Polygon &poly)
+{
+    Vec2crd ret{std::numeric_limits<coord_t>::min(),
+                std::numeric_limits<coord_t>::min()};
+
+    auto it = std::max_element(poly.points.begin(), poly.points.end(), vsort);
+    if (it != poly.points.end())
+        ret = std::max(ret, static_cast<const Vec2crd &>(*it), vsort);
+
+    return ret;
+}
+
+Vec2crd reference_vertex(const ExPolygon &expoly)
+{
+    return reference_vertex(expoly.contour);
+}
+
+Vec2crd reference_vertex(const Polygons &outline)
+{
+    Vec2crd ret{std::numeric_limits<coord_t>::min(),
+                std::numeric_limits<coord_t>::min()};
+
+    for (const Polygon &poly : outline)
+        ret = std::max(ret, reference_vertex(poly), vsort);
+
+    return ret;
+}
+
+Vec2crd reference_vertex(const ExPolygons &outline)
+{
+    Vec2crd ret{std::numeric_limits<coord_t>::min(),
+                std::numeric_limits<coord_t>::min()};
+
+    for (const ExPolygon &expoly : outline)
+        ret = std::max(ret, reference_vertex(expoly), vsort);
+
+    return ret;
+}
+
+Vec2crd min_vertex(const Polygon &poly)
+{
+    Vec2crd ret{std::numeric_limits<coord_t>::max(),
+                std::numeric_limits<coord_t>::max()};
+
+    auto it = std::min_element(poly.points.begin(), poly.points.end(), vsort);
+    if (it != poly.points.end())
+        ret = std::min(ret, static_cast<const Vec2crd&>(*it), vsort);
+
+    return ret;
+}
+
+// Find the vertex corresponding to the edge with minimum angle to X axis.
+// Only usable with CircularEdgeIterator<> template.
+template<class It> It find_min_anglex_edge(It from)
+{
+    bool found = false;
+    auto it = from;
+    while (!found ) {
+        found = !line_cmp(*it, *std::next(it));
+        ++it;
+    }
+
+    return it;
+}
+
+// Only usable if both fixed and movable polygon is convex. In that case,
+// their edges are already sorted by angle to X axis, only the starting
+// (lowest X axis) edge needs to be found first.
+void nfp_convex_convex(const Polygon &fixed, const Polygon &movable, Polygon &poly)
+{
+    if (fixed.empty() || movable.empty())
+        return;
+
+    // Clear poly and adjust its capacity. Nothing happens if poly is
+    // already sufficiently large and and empty.
+    poly.clear();
+    poly.points.reserve(fixed.size() + movable.size());
+
+    // Find starting positions on the fixed and moving polygons
+    auto it_fx = find_min_anglex_edge(CircularEdgeIterator{fixed});
+    auto it_mv = find_min_anglex_edge(CircularReverseEdgeIterator{movable});
+
+    // End positions are at the same vertex after completing one full circle
+    auto end_fx = it_fx + fixed.size();
+    auto end_mv = it_mv + movable.size();
+
+    // Pos zero is just fine as starting point:
+    poly.points.emplace_back(0, 0);
+
+    // Output iterator adapter for std::merge
+    struct OutItAdaptor {
+        using value_type [[maybe_unused]] = Line;
+        using difference_type [[maybe_unused]] = std::ptrdiff_t;
+        using pointer [[maybe_unused]] = Line*;
+        using reference [[maybe_unused]] = Line& ;
+        using iterator_category [[maybe_unused]] = std::output_iterator_tag;
+
+        Polygon *outpoly;
+        OutItAdaptor(Polygon &out) : outpoly{&out} {}
+
+        OutItAdaptor &operator *() { return *this; }
+        void operator=(const Line &l)
+        {
+            // Yielding l.b, offsetted so that l.a touches the last vertex in
+            // in outpoly
+            outpoly->points.emplace_back(l.b + outpoly->back() - l.a);
+        }
+
+        OutItAdaptor& operator++() { return *this; };
+    };
+
+    // Use std algo to merge the edges from the two polygons
+    std::merge(it_fx, end_fx, it_mv, end_mv, OutItAdaptor{poly}, line_cmp);
+}
+
+Polygon nfp_convex_convex(const Polygon &fixed, const Polygon &movable)
+{
+    Polygon ret;
+    nfp_convex_convex(fixed, movable, ret);
+
+    return ret;
+}
+
+static void buildPolygon(const std::vector<Line>& edgelist,
+                         Polygon& rpoly,
+                         Point& top_nfp)
+{
+    auto& rsh = rpoly.points;
+
+    rsh.reserve(2 * edgelist.size());
+
+    // Add the two vertices from the first edge into the final polygon.
+    rsh.emplace_back(edgelist.front().a);
+    rsh.emplace_back(edgelist.front().b);
+
+    // Sorting function for the nfp reference vertex search
+
+    // the reference (rightmost top) vertex so far
+    top_nfp = *std::max_element(std::cbegin(rsh), std::cend(rsh), vsort);
+
+    auto tmp = std::next(std::begin(rsh));
+
+    // Construct final nfp by placing each edge to the end of the previous
+    for(auto eit = std::next(edgelist.begin()); eit != edgelist.end(); ++eit) {
+        auto d = *tmp - eit->a;
+        Vec2crd p = eit->b + d;
+
+        rsh.emplace_back(p);
+
+        // Set the new reference vertex
+        if (vsort(top_nfp, p))
+            top_nfp = p;
+
+        tmp = std::next(tmp);
+    }
+}
+
+Polygon nfp_convex_convex_legacy(const Polygon &fixed, const Polygon &movable)
+{
+    assert (!fixed.empty());
+    assert (!movable.empty());
+
+    Polygon rsh;   // Final nfp placeholder
+    Point   max_nfp;
+    std::vector<Line> edgelist;
+
+    auto cap = fixed.points.size() + movable.points.size();
+
+    // Reserve the needed memory
+    edgelist.reserve(cap);
+    rsh.points.reserve(cap);
+
+    auto add_edge = [&edgelist](const Point &v1, const Point &v2) {
+        Line e{v1, v2};
+        if ((e.b - e.a).cast<int64_t>().squaredNorm() > 0)
+            edgelist.emplace_back(e);
+    };
+
+    Point max_fixed = fixed.points.front();
+    { // place all edges from fixed into edgelist
+        auto first = std::cbegin(fixed);
+        auto next = std::next(first);
+
+        while(next != std::cend(fixed)) {
+            add_edge(*(first), *(next));
+            max_fixed = std::max(max_fixed, *first, vsort);
+
+            ++first; ++next;
+        }
+
+        add_edge(*std::crbegin(fixed), *std::cbegin(fixed));
+        max_fixed = std::max(max_fixed, *std::crbegin(fixed), vsort);
+    }
+
+    Point max_movable = movable.points.front();
+    Point min_movable = movable.points.front();
+    { // place all edges from movable into edgelist
+        auto first = std::cbegin(movable);
+        auto next = std::next(first);
+
+        while(next != std::cend(movable)) {
+            add_edge(*(next), *(first));
+            min_movable = std::min(min_movable, *first, vsort);
+            max_movable = std::max(max_movable, *first, vsort);
+
+            ++first; ++next;
+        }
+
+        add_edge(*std::cbegin(movable), *std::crbegin(movable));
+        min_movable = std::min(min_movable, *std::crbegin(movable), vsort);
+        max_movable = std::max(max_movable, *std::crbegin(movable), vsort);
+    }
+
+    std::sort(edgelist.begin(), edgelist.end(), line_cmp);
+
+    buildPolygon(edgelist, rsh, max_nfp);
+
+    auto dtouch = max_fixed - min_movable;
+    auto top_other = max_movable + dtouch;
+    auto dnfp = top_other - max_nfp;
+    rsh.translate(dnfp);
+
+    return rsh;
+}
+
+} // namespace Slic3r
+
+#endif // NFP_CPP

src/libslic3r/Arrange/Core/NFP/NFP.hpp

@@ -0,0 +1,50 @@
+#ifndef NFP_HPP
+#define NFP_HPP
+
+#include <libslic3r/ExPolygon.hpp>
+#include <libslic3r/Arrange/Core/Beds.hpp>
+
+namespace Slic3r {
+
+template<class Unit = int64_t, class T>
+Unit dotperp(const Vec<2, T> &a, const Vec<2, T> &b)
+{
+    return Unit(a.x()) * Unit(b.y()) - Unit(a.y()) * Unit(b.x());
+}
+
+// Convex-Convex nfp in linear time (fixed.size() + movable.size()),
+// no memory allocations (if out param is used).
+// FIXME: Currently broken for very sharp triangles.
+Polygon nfp_convex_convex(const Polygon &fixed, const Polygon &movable);
+void nfp_convex_convex(const Polygon &fixed, const Polygon &movable, Polygon &out);
+Polygon nfp_convex_convex_legacy(const Polygon &fixed, const Polygon &movable);
+
+Polygon ifp_convex_convex(const Polygon &fixed, const Polygon &movable);
+
+ExPolygons ifp_convex(const arr2::RectangleBed &bed, const Polygon &convexpoly);
+ExPolygons ifp_convex(const arr2::CircleBed &bed, const Polygon &convexpoly);
+ExPolygons ifp_convex(const arr2::IrregularBed &bed, const Polygon &convexpoly);
+inline ExPolygons ifp_convex(const arr2::InfiniteBed &bed, const Polygon &convexpoly)
+{
+    return {};
+}
+
+inline ExPolygons ifp_convex(const arr2::ArrangeBed &bed, const Polygon &convexpoly)
+{
+    ExPolygons ret;
+    auto visitor = [&ret, &convexpoly](const auto &b) { ret = ifp_convex(b, convexpoly); };
+    boost::apply_visitor(visitor, bed);
+
+    return ret;
+}
+
+Vec2crd reference_vertex(const Polygon &outline);
+Vec2crd reference_vertex(const ExPolygon &outline);
+Vec2crd reference_vertex(const Polygons &outline);
+Vec2crd reference_vertex(const ExPolygons &outline);
+
+Vec2crd min_vertex(const Polygon &outline);
+
+} // namespace Slic3r
+
+#endif // NFP_HPP

src/libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp

@@ -0,0 +1,196 @@
+#ifndef NFPARRANGEITEMTRAITS_HPP
+#define NFPARRANGEITEMTRAITS_HPP
+
+#include <numeric>
+
+#include "libslic3r/Arrange/Core/ArrangeBase.hpp"
+
+#include "libslic3r/ExPolygon.hpp"
+#include "libslic3r/BoundingBox.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+// Additional methods that an ArrangeItem object has to implement in order
+// to be usable with PackStrategyNFP.
+template<class ArrItem, class En = void> struct NFPArrangeItemTraits_
+{
+    template<class Context, class Bed, class StopCond = DefaultStopCondition>
+    static ExPolygons calculate_nfp(const ArrItem &item,
+                                    const Context &packing_context,
+                                    const Bed &bed,
+                                    StopCond stop_condition = {})
+    {
+        static_assert(always_false<ArrItem>::value,
+                      "NFP unimplemented for this item type.");
+        return {};
+    }
+
+    static Vec2crd reference_vertex(const ArrItem &item)
+    {
+        return item.reference_vertex();
+    }
+
+    static BoundingBox envelope_bounding_box(const ArrItem &itm)
+    {
+        return itm.envelope_bounding_box();
+    }
+
+    static BoundingBox fixed_bounding_box(const ArrItem &itm)
+    {
+        return itm.fixed_bounding_box();
+    }
+
+    static const Polygons & envelope_outline(const ArrItem &itm)
+    {
+        return itm.envelope_outline();
+    }
+
+    static const Polygons & fixed_outline(const ArrItem &itm)
+    {
+        return itm.fixed_outline();
+    }
+
+    static const Polygon & envelope_convex_hull(const ArrItem &itm)
+    {
+        return itm.envelope_convex_hull();
+    }
+
+    static const Polygon & fixed_convex_hull(const ArrItem &itm)
+    {
+        return itm.fixed_convex_hull();
+    }
+
+    static double envelope_area(const ArrItem &itm)
+    {
+        return itm.envelope_area();
+    }
+
+    static double fixed_area(const ArrItem &itm)
+    {
+        return itm.fixed_area();
+    }
+
+    static auto allowed_rotations(const ArrItem &)
+    {
+        return std::array{0.};
+    }
+
+    static Vec2crd fixed_centroid(const ArrItem &itm)
+    {
+        return fixed_bounding_box(itm).center();
+    }
+
+    static Vec2crd envelope_centroid(const ArrItem &itm)
+    {
+        return envelope_bounding_box(itm).center();
+    }
+};
+
+template<class T>
+using NFPArrangeItemTraits = NFPArrangeItemTraits_<StripCVRef<T>>;
+
+template<class ArrItem,
+         class Context,
+         class Bed,
+         class StopCond = DefaultStopCondition>
+ExPolygons calculate_nfp(const ArrItem &itm,
+                         const Context &context,
+                         const Bed &bed,
+                         StopCond stopcond = {})
+{
+    return NFPArrangeItemTraits<ArrItem>::calculate_nfp(itm, context, bed,
+                                                        std::move(stopcond));
+}
+
+template<class ArrItem> Vec2crd reference_vertex(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::reference_vertex(itm);
+}
+
+template<class ArrItem> BoundingBox envelope_bounding_box(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::envelope_bounding_box(itm);
+}
+
+template<class ArrItem> BoundingBox fixed_bounding_box(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::fixed_bounding_box(itm);
+}
+
+template<class ArrItem> decltype(auto) envelope_convex_hull(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::envelope_convex_hull(itm);
+}
+
+template<class ArrItem> decltype(auto) fixed_convex_hull(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::fixed_convex_hull(itm);
+}
+
+template<class ArrItem> decltype(auto) envelope_outline(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::envelope_outline(itm);
+}
+
+template<class ArrItem> decltype(auto) fixed_outline(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::fixed_outline(itm);
+}
+
+template<class ArrItem> double envelope_area(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::envelope_area(itm);
+}
+
+template<class ArrItem> double fixed_area(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::fixed_area(itm);
+}
+
+template<class ArrItem> Vec2crd fixed_centroid(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::fixed_centroid(itm);
+}
+
+template<class ArrItem> Vec2crd envelope_centroid(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::envelope_centroid(itm);
+}
+
+template<class ArrItem>
+auto allowed_rotations(const ArrItem &itm)
+{
+    return NFPArrangeItemTraits<ArrItem>::allowed_rotations(itm);
+}
+
+template<class It>
+BoundingBox bounding_box(const Range<It> &itms) noexcept
+{
+    auto pilebb =
+        std::accumulate(itms.begin(), itms.end(), BoundingBox{},
+                        [](BoundingBox bb, const auto &itm) {
+                            bb.merge(fixed_bounding_box(itm));
+                            return bb;
+                        });
+
+    return pilebb;
+}
+
+template<class It>
+BoundingBox bounding_box_on_bedidx(const Range<It> &itms, int bed_index) noexcept
+{
+    auto pilebb =
+        std::accumulate(itms.begin(), itms.end(), BoundingBox{},
+                        [bed_index](BoundingBox bb, const auto &itm) {
+                            if (bed_index == get_bed_index(itm))
+                                bb.merge(fixed_bounding_box(itm));
+
+                            return bb;
+                        });
+
+    return pilebb;
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGEITEMTRAITSNFP_HPP

src/libslic3r/Arrange/Core/NFP/NFPConcave_CGAL.cpp

@@ -0,0 +1,111 @@
+#include "NFP.hpp"
+#include "NFPConcave_CGAL.hpp"
+
+#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
+#include <CGAL/partition_2.h>
+#include <CGAL/Partition_traits_2.h>
+#include <CGAL/property_map.h>
+#include <CGAL/Polygon_vertical_decomposition_2.h>
+
+#include "libslic3r/ClipperUtils.hpp"
+
+namespace Slic3r {
+
+using K = CGAL::Exact_predicates_inexact_constructions_kernel;
+using Partition_traits_2 = CGAL::Partition_traits_2<K, CGAL::Pointer_property_map<K::Point_2>::type >;
+using Point_2 = Partition_traits_2::Point_2;
+using Polygon_2 = Partition_traits_2::Polygon_2;  // a polygon of indices
+
+ExPolygons nfp_concave_concave_cgal(const ExPolygon &fixed, const ExPolygon &movable)
+{
+    Polygons fixed_decomp = convex_decomposition_cgal(fixed);
+    Polygons movable_decomp = convex_decomposition_cgal(movable);
+
+    auto refs_mv = reserve_vector<Vec2crd>(movable_decomp.size());
+
+    for (const Polygon &p : movable_decomp)
+        refs_mv.emplace_back(reference_vertex(p));
+
+    auto nfps = reserve_polygons(fixed_decomp.size() *movable_decomp.size());
+
+    Vec2crd ref_whole = reference_vertex(movable);
+    for (const Polygon &fixed_part : fixed_decomp) {
+        size_t mvi = 0;
+        for (const Polygon &movable_part : movable_decomp) {
+            Polygon subnfp = nfp_convex_convex(fixed_part, movable_part);
+            const Vec2crd &ref_mp = refs_mv[mvi];
+            auto d = ref_whole - ref_mp;
+            subnfp.translate(d);
+            nfps.emplace_back(subnfp);
+            mvi++;
+        }
+    }
+
+    return union_ex(nfps);
+}
+
+// TODO: holes
+Polygons convex_decomposition_cgal(const ExPolygon &expoly)
+{
+    CGAL::Polygon_vertical_decomposition_2<K> decomp;
+
+    CGAL::Polygon_2<K> contour;
+    for (auto &p : expoly.contour.points)
+        contour.push_back({unscaled(p.x()), unscaled(p.y())});
+
+    CGAL::Polygon_with_holes_2<K> cgalpoly{contour};
+    for (const Polygon &h : expoly.holes) {
+        CGAL::Polygon_2<K> hole;
+        for (auto &p : h.points)
+            hole.push_back({unscaled(p.x()), unscaled(p.y())});
+
+        cgalpoly.add_hole(hole);
+    }
+
+    std::vector<CGAL::Polygon_2<K>> out;
+    decomp(cgalpoly, std::back_inserter(out));
+
+    Polygons ret;
+    for (auto &pwh : out) {
+        Polygon poly;
+        for (auto &p : pwh)
+            poly.points.emplace_back(scaled(p.x()), scaled(p.y()));
+        ret.emplace_back(std::move(poly));
+    }
+
+    return ret; //convex_decomposition_cgal(expoly.contour);
+}
+
+Polygons convex_decomposition_cgal(const Polygon &poly)
+{
+    auto pts = reserve_vector<K::Point_2>(poly.size());
+
+    for (const Point &p : poly.points)
+        pts.emplace_back(unscaled(p.x()), unscaled(p.y()));
+
+    Partition_traits_2 traits(CGAL::make_property_map(pts));
+
+    Polygon_2 polyidx;
+    for (size_t i = 0; i < pts.size(); ++i)
+        polyidx.push_back(i);
+
+    std::vector<Polygon_2> outp;
+
+    CGAL::optimal_convex_partition_2(polyidx.vertices_begin(),
+                                     polyidx.vertices_end(),
+                                     std::back_inserter(outp),
+                                     traits);
+
+    Polygons ret;
+    for (const Polygon_2& poly : outp){
+        Polygon r;
+        for(Point_2 p : poly.container())
+            r.points.emplace_back(scaled(pts[p].x()), scaled(pts[p].y()));
+
+        ret.emplace_back(std::move(r));
+    }
+
+    return ret;
+}
+
+} // namespace Slic3r

src/libslic3r/Arrange/Core/NFP/NFPConcave_CGAL.hpp

@@ -0,0 +1,14 @@
+#ifndef NFPCONCAVE_CGAL_HPP
+#define NFPCONCAVE_CGAL_HPP
+
+#include <libslic3r/ExPolygon.hpp>
+
+namespace Slic3r {
+
+Polygons convex_decomposition_cgal(const Polygon &expoly);
+Polygons convex_decomposition_cgal(const ExPolygon &expoly);
+ExPolygons nfp_concave_concave_cgal(const ExPolygon &fixed, const ExPolygon &movable);
+
+} // namespace Slic3r
+
+#endif // NFPCONCAVE_CGAL_HPP

src/libslic3r/Arrange/Core/NFP/NFPConcave_Tesselate.cpp

@@ -0,0 +1,70 @@
+#include "NFPConcave_Tesselate.hpp"
+
+#include <libslic3r/ClipperUtils.hpp>
+#include <libslic3r/Tesselate.hpp>
+
+#include "NFP.hpp"
+
+namespace Slic3r {
+
+Polygons convex_decomposition_tess(const Polygon &expoly)
+{
+    return convex_decomposition_tess(ExPolygon{expoly});
+}
+
+Polygons convex_decomposition_tess(const ExPolygon &expoly)
+{
+    std::vector<Vec2d> tr = Slic3r::triangulate_expolygon_2d(expoly);
+
+    auto ret = Slic3r::reserve_polygons(tr.size() / 3);
+    for (size_t i = 0; i < tr.size(); i += 3) {
+        ret.emplace_back(
+            Polygon{scaled(tr[i]), scaled(tr[i + 1]), scaled(tr[i + 2])});
+    }
+
+    return ret;
+}
+
+Polygons convex_decomposition_tess(const ExPolygons &expolys)
+{
+    constexpr size_t AvgTriangleCountGuess = 50;
+
+    auto ret = reserve_polygons(AvgTriangleCountGuess * expolys.size());
+    for (const ExPolygon &expoly : expolys) {
+        Polygons convparts = convex_decomposition_tess(expoly);
+        std::move(convparts.begin(), convparts.end(), std::back_inserter(ret));
+    }
+
+    return ret;
+}
+
+ExPolygons nfp_concave_concave_tess(const ExPolygon &fixed,
+                                    const ExPolygon &movable)
+{
+    Polygons fixed_decomp = convex_decomposition_tess(fixed);
+    Polygons movable_decomp = convex_decomposition_tess(movable);
+
+    auto refs_mv = reserve_vector<Vec2crd>(movable_decomp.size());
+
+    for (const Polygon &p : movable_decomp)
+        refs_mv.emplace_back(reference_vertex(p));
+
+    auto nfps = reserve_polygons(fixed_decomp.size() * movable_decomp.size());
+
+    Vec2crd ref_whole = reference_vertex(movable);
+    for (const Polygon &fixed_part : fixed_decomp) {
+        size_t mvi = 0;
+        for (const Polygon &movable_part : movable_decomp) {
+            Polygon subnfp = nfp_convex_convex(fixed_part, movable_part);
+            const Vec2crd &ref_mp = refs_mv[mvi];
+            auto d = ref_whole - ref_mp;
+            subnfp.translate(d);
+            nfps.emplace_back(subnfp);
+            mvi++;
+        }
+    }
+
+    return union_ex(nfps);
+}
+
+} // namespace Slic3r

src/libslic3r/Arrange/Core/NFP/NFPConcave_Tesselate.hpp

@@ -0,0 +1,15 @@
+#ifndef NFPCONCAVE_TESSELATE_HPP
+#define NFPCONCAVE_TESSELATE_HPP
+
+#include <libslic3r/ExPolygon.hpp>
+
+namespace Slic3r {
+
+Polygons convex_decomposition_tess(const Polygon &expoly);
+Polygons convex_decomposition_tess(const ExPolygon &expoly);
+Polygons convex_decomposition_tess(const ExPolygons &expolys);
+ExPolygons nfp_concave_concave_tess(const ExPolygon &fixed, const ExPolygon &movable);
+
+} // namespace Slic3r
+
+#endif // NFPCONCAVE_TESSELATE_HPP

src/libslic3r/Arrange/Core/NFP/PackStrategyNFP.hpp

@@ -0,0 +1,285 @@
+#ifndef PACKSTRATEGYNFP_HPP
+#define PACKSTRATEGYNFP_HPP
+
+#include "libslic3r/Arrange/Core/ArrangeBase.hpp"
+
+#include "EdgeCache.hpp"
+#include "Kernels/KernelTraits.hpp"
+
+#include "NFPArrangeItemTraits.hpp"
+
+#include "libslic3r/Optimize/NLoptOptimizer.hpp"
+#include "libslic3r/Execution/ExecutionSeq.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+struct NFPPackingTag{};
+
+struct DummyArrangeKernel
+{
+    template<class ArrItem>
+    double placement_fitness(const ArrItem &itm, const Vec2crd &dest_pos) const
+    {
+        return NaNd;
+    }
+
+    template<class ArrItem, class Bed, class Context, class RemIt>
+    bool on_start_packing(ArrItem            &itm,
+                          const Bed          &bed,
+                          const Context      &packing_context,
+                          const Range<RemIt> &remaining_items)
+    {
+        return true;
+    }
+
+    template<class ArrItem> bool on_item_packed(ArrItem &itm) { return true; }
+};
+
+template<class Strategy> using OptAlg = typename Strategy::OptAlg;
+
+template<class ArrangeKernel = DummyArrangeKernel,
+         class ExecPolicy = ExecutionSeq,
+         class OptMethod = opt::AlgNLoptSubplex,
+         class StopCond  = DefaultStopCondition>
+struct PackStrategyNFP {
+    using OptAlg = OptMethod;
+
+    ArrangeKernel kernel;
+    ExecPolicy ep;
+    double accuracy = 1.;
+    opt::Optimizer<OptMethod> solver;
+    StopCond stop_condition;
+
+    PackStrategyNFP(opt::Optimizer<OptMethod> slv,
+                    ArrangeKernel k = {},
+                    ExecPolicy execpolicy = {},
+                    double accur = 1.,
+                    StopCond stop_cond = {})
+        : kernel{std::move(k)},
+          ep{std::move(execpolicy)},
+          accuracy{accur},
+          solver{std::move(slv)},
+          stop_condition{std::move(stop_cond)}
+    {}
+
+    PackStrategyNFP(ArrangeKernel k = {},
+                    ExecPolicy execpolicy = {},
+                    double accur = 1.,
+                    StopCond stop_cond = {})
+        : PackStrategyNFP{opt::Optimizer<OptMethod>{}, std::move(k),
+                          std::move(execpolicy), accur, std::move(stop_cond)}
+    {
+        // Defaults for AlgNLoptSubplex
+        auto iters = static_cast<unsigned>(std::floor(1000 * accuracy));
+        auto optparams =
+            opt::StopCriteria{}.max_iterations(iters).rel_score_diff(
+                1e-20) /*.abs_score_diff(1e-20)*/;
+
+        solver.set_criteria(optparams);
+    }
+};
+
+template<class...Args>
+struct PackStrategyTag_<PackStrategyNFP<Args...>>
+{
+    using Tag = NFPPackingTag;
+};
+
+
+template<class ArrItem, class Bed, class PStrategy>
+double pick_best_spot_on_nfp_verts_only(ArrItem            &item,
+                                        const ExPolygons   &nfp,
+                                        const Bed          &bed,
+                                        const PStrategy    &strategy)
+{
+    using KernelT = KernelTraits<decltype(strategy.kernel)>;
+
+    auto    score   = -std::numeric_limits<double>::infinity();
+    Vec2crd orig_tr = get_translation(item);
+    Vec2crd translation{0, 0};
+
+    auto eval_fitness = [&score, &strategy, &item, &translation,
+                         &orig_tr](const Vec2crd &p) {
+        set_translation(item, orig_tr);
+        Vec2crd ref_v = reference_vertex(item);
+        Vec2crd tr    = p - ref_v;
+        double fitness = KernelT::placement_fitness(strategy.kernel, item, tr);
+        if (fitness > score) {
+            score       = fitness;
+            translation = tr;
+        }
+    };
+
+    for (const ExPolygon &expoly : nfp) {
+        for (const Point &p : expoly.contour) {
+            eval_fitness(p);
+        }
+
+        for (const Polygon &h : expoly.holes)
+            for (const Point &p : h.points)
+                eval_fitness(p);
+    }
+
+    set_translation(item, orig_tr + translation);
+
+    return score;
+}
+
+struct CornerResult
+{
+    size_t         contour_id;
+    opt::Result<1> oresult;
+};
+
+template<class ArrItem, class Bed, class... Args>
+double pick_best_spot_on_nfp(ArrItem                        &item,
+                             const ExPolygons               &nfp,
+                             const Bed                      &bed,
+                             const PackStrategyNFP<Args...> &strategy)
+{
+    auto &ex_policy = strategy.ep;
+    using KernelT = KernelTraits<decltype(strategy.kernel)>;
+
+    auto score = -std::numeric_limits<double>::infinity();
+    Vec2crd orig_tr = get_translation(item);
+    Vec2crd translation{0, 0};
+    Vec2crd ref_v = reference_vertex(item);
+
+    auto edge_caches = reserve_vector<EdgeCache>(nfp.size());
+    auto sample_sets = reserve_vector<std::vector<ContourLocation>>(
+        nfp.size());
+
+    for (const ExPolygon &expoly : nfp) {
+        edge_caches.emplace_back(EdgeCache{&expoly});
+        edge_caches.back().sample_contour(strategy.accuracy,
+                                          sample_sets.emplace_back());
+    }
+
+    auto nthreads = execution::max_concurrency(ex_policy);
+
+    std::vector<CornerResult> gresults(edge_caches.size());
+
+    auto resultcmp = [](auto &a, auto &b) {
+        return a.oresult.score < b.oresult.score;
+    };
+
+    execution::for_each(
+        ex_policy, size_t(0), edge_caches.size(),
+        [&](size_t edge_cache_idx) {
+            auto &ec_contour = edge_caches[edge_cache_idx];
+            auto &corners = sample_sets[edge_cache_idx];
+            std::vector<CornerResult> results(corners.size());
+
+            auto cornerfn = [&](size_t i) {
+                ContourLocation cr = corners[i];
+                auto objfn = [&](opt::Input<1> &in) {
+                    Vec2crd p = ec_contour.coords(ContourLocation{cr.contour_id, in[0]});
+                    Vec2crd tr = p - ref_v;
+
+                    return KernelT::placement_fitness(strategy.kernel, item, tr);
+                };
+
+                // Assuming that solver is a lightweight object
+                auto solver = strategy.solver;
+                solver.to_max();
+                auto oresult = solver.optimize(objfn,
+                                               opt::initvals({cr.dist}),
+                                               opt::bounds({{0., 1.}}));
+
+                results[i] = CornerResult{cr.contour_id, oresult};
+            };
+
+            execution::for_each(ex_policy, size_t(0), results.size(),
+                                cornerfn, nthreads);
+
+            auto it = std::max_element(results.begin(), results.end(),
+                                       resultcmp);
+
+            if (it != results.end())
+                gresults[edge_cache_idx] = *it;
+        },
+        nthreads);
+
+    auto it = std::max_element(gresults.begin(), gresults.end(), resultcmp);
+    if (it != gresults.end()) {
+        score = it->oresult.score;
+        size_t path_id = std::distance(gresults.begin(), it);
+        size_t contour_id = it->contour_id;
+        double dist = it->oresult.optimum[0];
+
+        Vec2crd pos = edge_caches[path_id].coords(ContourLocation{contour_id, dist});
+        Vec2crd tr = pos - ref_v;
+
+        set_translation(item, orig_tr + tr);
+    }
+
+    return score;
+}
+
+template<class Strategy, class ArrItem, class Bed, class RemIt>
+bool pack(Strategy &strategy,
+          const Bed &bed,
+          ArrItem &item,
+          const PackStrategyContext<Strategy, ArrItem> &packing_context,
+          const Range<RemIt> &remaining_items,
+          const NFPPackingTag &)
+{
+    using KernelT = KernelTraits<decltype(strategy.kernel)>;
+
+    // The kernel might pack the item immediately
+    bool packed = KernelT::on_start_packing(strategy.kernel, item, bed,
+                                            packing_context, remaining_items);
+
+    double  orig_rot    = get_rotation(item);
+    double  final_rot   = 0.;
+    double  final_score = -std::numeric_limits<double>::infinity();
+    Vec2crd orig_tr     = get_translation(item);
+    Vec2crd final_tr    = orig_tr;
+
+    bool cancelled = strategy.stop_condition();
+    const auto & rotations = allowed_rotations(item);
+
+    // Check all rotations but only if item is not already packed
+    for (auto rot_it = rotations.begin();
+         !cancelled && !packed && rot_it != rotations.end(); ++rot_it) {
+
+        double rot = *rot_it;
+
+        set_rotation(item, orig_rot + rot);
+        set_translation(item, orig_tr);
+
+        auto nfp = calculate_nfp(item, packing_context, bed,
+                                 strategy.stop_condition);
+        double score = NaNd;
+        if (!nfp.empty()) {
+            score = pick_best_spot_on_nfp(item, nfp, bed, strategy);
+
+            cancelled = strategy.stop_condition();
+            if (score > final_score) {
+                final_score = score;
+                final_rot   = rot;
+                final_tr    = get_translation(item);
+            }
+        }
+    }
+
+    // If the score is not valid, and the item is not already packed, or
+    // the packing was cancelled asynchronously by stop condition, then
+    // discard the packing
+    bool is_score_valid = !std::isnan(final_score) && !std::isinf(final_score);
+    packed = !cancelled && (packed || is_score_valid);
+
+    if (packed) {
+        set_translation(item, final_tr);
+        set_rotation(item, orig_rot + final_rot);
+
+        // Finally, consult the kernel if the packing is sane
+        packed = KernelT::on_item_packed(strategy.kernel, item);
+    }
+
+    return packed;
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // PACKSTRATEGYNFP_HPP

src/libslic3r/Arrange/Core/NFP/RectangleOverfitPackingStrategy.hpp

@@ -0,0 +1,141 @@
+#ifndef RECTANGLEOVERFITPACKINGSTRATEGY_HPP
+#define RECTANGLEOVERFITPACKINGSTRATEGY_HPP
+
+#include "Kernels/RectangleOverfitKernelWrapper.hpp"
+
+#include "libslic3r/Arrange/Core/NFP/PackStrategyNFP.hpp"
+#include "libslic3r/Arrange/Core/Beds.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+using PostAlignmentFn = std::function<Vec2crd(const BoundingBox &bedbb,
+                                              const BoundingBox &pilebb)>;
+
+struct CenterAlignmentFn {
+    Vec2crd operator() (const BoundingBox &bedbb,
+                        const BoundingBox &pilebb)
+    {
+        return bedbb.center() - pilebb.center();
+    }
+};
+
+template<class ArrItem>
+struct RectangleOverfitPackingContext : public DefaultPackingContext<ArrItem>
+{
+    BoundingBox limits;
+    int bed_index;
+    PostAlignmentFn post_alignment_fn;
+
+    explicit RectangleOverfitPackingContext(const BoundingBox limits,
+                     int bedidx,
+                     PostAlignmentFn alignfn = CenterAlignmentFn{})
+        : limits{limits}, bed_index{bedidx}, post_alignment_fn{alignfn}
+    {}
+
+    void align_pile()
+    {
+        // Here, the post alignment can be safely done. No throwing
+        // functions are called!
+        if (fixed_items_range(*this).empty()) {
+            auto itms = packed_items_range(*this);
+            auto pilebb = bounding_box(itms);
+
+            for (auto &itm : itms) {
+                translate(itm, post_alignment_fn(limits, pilebb));
+            }
+        }
+    }
+
+    ~RectangleOverfitPackingContext() { align_pile(); }
+};
+
+// With rectange bed, and no fixed items, an infinite bed with
+// RectangleOverfitKernelWrapper can produce better results than a pure
+// RectangleBed with inner-fit polygon calculation.
+template<class ...Args>
+struct RectangleOverfitPackingStrategy {
+    PackStrategyNFP<Args...> base_strategy;
+
+    PostAlignmentFn post_alignment_fn = CenterAlignmentFn{};
+
+    template<class ArrItem>
+    using Context = RectangleOverfitPackingContext<ArrItem>;
+
+    RectangleOverfitPackingStrategy(PackStrategyNFP<Args...> s,
+                                    PostAlignmentFn post_align_fn)
+        : base_strategy{std::move(s)}, post_alignment_fn{post_align_fn}
+    {}
+
+    RectangleOverfitPackingStrategy(PackStrategyNFP<Args...> s)
+        : base_strategy{std::move(s)}
+    {}
+};
+
+struct RectangleOverfitPackingStrategyTag {};
+
+template<class... Args>
+struct PackStrategyTag_<RectangleOverfitPackingStrategy<Args...>> {
+    using Tag = RectangleOverfitPackingStrategyTag;
+};
+
+template<class... Args>
+struct PackStrategyTraits_<RectangleOverfitPackingStrategy<Args...>> {
+    template<class ArrItem>
+    using Context = typename RectangleOverfitPackingStrategy<
+        Args...>::template Context<StripCVRef<ArrItem>>;
+
+    template<class ArrItem, class Bed>
+    static Context<ArrItem> create_context(
+        RectangleOverfitPackingStrategy<Args...> &ps,
+        const Bed &bed,
+        int bed_index)
+    {
+        return Context<ArrItem>{bounding_box(bed), bed_index,
+                                ps.post_alignment_fn};
+    }
+};
+
+template<class ArrItem>
+struct PackingContextTraits_<RectangleOverfitPackingContext<ArrItem>>
+    : public PackingContextTraits_<DefaultPackingContext<ArrItem>>
+{
+    static void add_packed_item(RectangleOverfitPackingContext<ArrItem> &ctx, ArrItem &itm)
+    {
+        ctx.add_packed_item(itm);
+
+        // to prevent coords going out of range
+        ctx.align_pile();
+    }
+};
+
+template<class Strategy, class ArrItem, class Bed, class RemIt>
+bool pack(Strategy &strategy,
+          const Bed &bed,
+          ArrItem &item,
+          const PackStrategyContext<Strategy, ArrItem> &packing_context,
+          const Range<RemIt> &remaining_items,
+          const RectangleOverfitPackingStrategyTag &)
+{
+    bool ret = false;
+
+    if (fixed_items_range(packing_context).empty()) {
+        auto &base = strategy.base_strategy;
+        PackStrategyNFP modded_strategy{
+            base.solver,
+            RectangleOverfitKernelWrapper{base.kernel, packing_context.limits},
+            base.ep, base.accuracy};
+
+        ret = pack(modded_strategy,
+                   InfiniteBed{packing_context.limits.center()}, item,
+                   packing_context, remaining_items, NFPPackingTag{});
+    } else {
+        ret = pack(strategy.base_strategy, bed, item, packing_context,
+                   remaining_items, NFPPackingTag{});
+    }
+
+    return ret;
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // RECTANGLEOVERFITPACKINGSTRATEGY_HPP

src/libslic3r/Arrange/Core/PackingContext.hpp

@@ -0,0 +1,124 @@
+#ifndef PACKINGCONTEXT_HPP
+#define PACKINGCONTEXT_HPP
+
+#include "ArrangeItemTraits.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+template<class Ctx, class En = void>
+struct PackingContextTraits_ {
+    template<class ArrItem>
+    static void add_fixed_item(Ctx &ctx, const ArrItem &itm)
+    {
+        ctx.add_fixed_item(itm);
+    }
+
+    template<class ArrItem>
+    static void add_packed_item(Ctx &ctx, ArrItem &itm)
+    {
+        ctx.add_packed_item(itm);
+    }
+
+    // returns a range of all packed items in the context ctx
+    static auto all_items_range(const Ctx &ctx)
+    {
+        return ctx.all_items_range();
+    }
+
+    static auto fixed_items_range(const Ctx &ctx)
+    {
+        return ctx.fixed_items_range();
+    }
+
+    static auto packed_items_range(const Ctx &ctx)
+    {
+        return ctx.packed_items_range();
+    }
+
+    static auto packed_items_range(Ctx &ctx)
+    {
+        return ctx.packed_items_range();
+    }
+};
+
+template<class Ctx, class ArrItem>
+void add_fixed_item(Ctx &ctx, const ArrItem &itm)
+{
+    PackingContextTraits_<StripCVRef<Ctx>>::add_fixed_item(ctx, itm);
+}
+
+template<class Ctx, class ArrItem>
+void add_packed_item(Ctx &ctx, ArrItem &itm)
+{
+    PackingContextTraits_<StripCVRef<Ctx>>::add_packed_item(ctx, itm);
+}
+
+template<class Ctx>
+auto all_items_range(const Ctx &ctx)
+{
+    return PackingContextTraits_<StripCVRef<Ctx>>::all_items_range(ctx);
+}
+
+template<class Ctx>
+auto fixed_items_range(const Ctx &ctx)
+{
+    return PackingContextTraits_<StripCVRef<Ctx>>::fixed_items_range(ctx);
+}
+
+template<class Ctx>
+auto packed_items_range(Ctx &&ctx)
+{
+    return PackingContextTraits_<StripCVRef<Ctx>>::packed_items_range(ctx);
+}
+
+template<class ArrItem>
+class DefaultPackingContext {
+    using ArrItemRaw = StripCVRef<ArrItem>;
+    std::vector<std::reference_wrapper<const ArrItemRaw>> m_fixed;
+    std::vector<std::reference_wrapper<ArrItemRaw>> m_packed;
+    std::vector<std::reference_wrapper<const ArrItemRaw>> m_items;
+
+public:
+    DefaultPackingContext() = default;
+
+    template<class It>
+    explicit DefaultPackingContext(const Range<It> &fixed_items)
+    {
+        std::copy(fixed_items.begin(), fixed_items.end(), std::back_inserter(m_fixed));
+        std::copy(fixed_items.begin(), fixed_items.end(), std::back_inserter(m_items));
+    }
+
+    auto all_items_range() const noexcept { return crange(m_items); }
+    auto fixed_items_range() const noexcept { return crange(m_fixed); }
+    auto packed_items_range() const noexcept { return crange(m_packed); }
+    auto packed_items_range() noexcept { return range(m_packed); }
+
+    void add_fixed_item(const ArrItem &itm)
+    {
+        m_fixed.emplace_back(itm);
+        m_items.emplace_back(itm);
+    }
+
+    void add_packed_item(ArrItem &itm)
+    {
+        m_packed.emplace_back(itm);
+        m_items.emplace_back(itm);
+    }
+};
+
+template<class It>
+auto default_context(const Range<It> &items)
+{
+    using ArrItem = StripCVRef<typename std::iterator_traits<It>::value_type>;
+    return DefaultPackingContext<ArrItem>{items};
+}
+
+template<class Cont, class ArrItem = typename Cont::value_type>
+auto default_context(const Cont &container)
+{
+    return DefaultPackingContext<ArrItem>{crange(container)};
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // PACKINGCONTEXT_HPP

src/libslic3r/Arrange/Items/ArbitraryDataStore.hpp

@@ -0,0 +1,91 @@
+#ifndef ARBITRARYDATASTORE_HPP
+#define ARBITRARYDATASTORE_HPP
+
+#include <string>
+#include <map>
+#include <any>
+
+#include "libslic3r/Arrange/Core/DataStoreTraits.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+// An associative container able to store and retrieve any data type.
+// Based on std::any
+class ArbitraryDataStore {
+    std::map<std::string, std::any> m_data;
+
+public:
+    template<class T> void add(const std::string &key, T &&data)
+    {
+        m_data[key] = std::any{std::forward<T>(data)};
+    }
+
+    void add(const std::string &key, std::any &&data)
+    {
+        m_data[key] = std::move(data);
+    }
+
+    // Return nullptr if the key does not exist or the stored data has a
+    // type other then T. Otherwise returns a pointer to the stored data.
+    template<class T> const T *get(const std::string &key) const
+    {
+        auto it = m_data.find(key);
+        return it != m_data.end() ? std::any_cast<T>(&(it->second)) :
+                                    nullptr;
+    }
+
+    // Same as above just not const.
+    template<class T> T *get(const std::string &key)
+    {
+        auto it = m_data.find(key);
+        return it != m_data.end() ? std::any_cast<T>(&(it->second)) : nullptr;
+    }
+
+    bool has_key(const std::string &key) const
+    {
+        auto it = m_data.find(key);
+        return it != m_data.end();
+    }
+};
+
+// Some items can be containers of arbitrary data stored under string keys.
+template<> struct DataStoreTraits_<ArbitraryDataStore>
+{
+    static constexpr bool Implemented = true;
+
+    template<class T>
+    static const T *get(const ArbitraryDataStore &s, const std::string &key)
+    {
+        return s.get<T>(key);
+    }
+
+    // Same as above just not const.
+    template<class T>
+    static T *get(ArbitraryDataStore &s, const std::string &key)
+    {
+        return s.get<T>(key);
+    }
+
+    template<class T>
+    static bool has_key(ArbitraryDataStore &s, const std::string &key)
+    {
+        return s.has_key(key);
+    }
+};
+
+template<> struct WritableDataStoreTraits_<ArbitraryDataStore>
+{
+    static constexpr bool Implemented = true;
+
+    template<class T>
+    static void set(ArbitraryDataStore &store,
+                    const std::string &key,
+                    T &&data)
+    {
+        store.add(key, std::forward<T>(data));
+    }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // ARBITRARYDATASTORE_HPP

src/libslic3r/Arrange/Items/ArrangeItem.cpp

@@ -0,0 +1,205 @@
+#include "ArrangeItem.hpp"
+
+#include "libslic3r/Arrange/Core/NFP/NFPConcave_Tesselate.hpp"
+
+#include "libslic3r/Arrange/ArrangeImpl.hpp"
+#include "libslic3r/Arrange/Tasks/ArrangeTaskImpl.hpp"
+#include "libslic3r/Arrange/Tasks/FillBedTaskImpl.hpp"
+#include "libslic3r/Arrange/Tasks/MultiplySelectionTaskImpl.hpp"
+
+#include "libslic3r/Geometry/ConvexHull.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+const Polygons &DecomposedShape::transformed_outline() const
+{
+    constexpr auto sc = scaled<double>(1.) * scaled<double>(1.);
+
+    if (!m_transformed_outline_valid) {
+        m_transformed_outline = contours();
+        for (Polygon &poly : m_transformed_outline) {
+            poly.rotate(rotation());
+            poly.translate(translation());
+        }
+
+        m_area = std::accumulate(m_transformed_outline.begin(),
+                                 m_transformed_outline.end(), 0.,
+                                 [sc](double s, const auto &p) {
+                                     return s + p.area() / sc;
+                                 });
+
+        m_convex_hull = Geometry::convex_hull(m_transformed_outline);
+        m_bounding_box = get_extents(m_convex_hull);
+
+        m_transformed_outline_valid = true;
+    }
+
+    return m_transformed_outline;
+}
+
+const Polygon &DecomposedShape::convex_hull() const
+{
+    if (!m_transformed_outline_valid)
+        transformed_outline();
+
+    return m_convex_hull;
+}
+
+const BoundingBox &DecomposedShape::bounding_box() const
+{
+    if (!m_transformed_outline_valid)
+        transformed_outline();
+
+    return m_bounding_box;
+}
+
+const Vec2crd &DecomposedShape::reference_vertex() const
+{
+    if (!m_reference_vertex_valid) {
+        m_reference_vertex = Slic3r::reference_vertex(transformed_outline());
+        m_refs.clear();
+        m_mins.clear();
+        m_refs.reserve(m_transformed_outline.size());
+        m_mins.reserve(m_transformed_outline.size());
+        for (auto &poly : m_transformed_outline) {
+            m_refs.emplace_back(Slic3r::reference_vertex(poly));
+            m_mins.emplace_back(Slic3r::min_vertex(poly));
+        }
+        m_reference_vertex_valid = true;
+    }
+
+    return m_reference_vertex;
+}
+
+const Vec2crd &DecomposedShape::reference_vertex(size_t i) const
+{
+    if (!m_reference_vertex_valid) {
+        reference_vertex();
+    }
+
+    return m_refs[i];
+}
+
+const Vec2crd &DecomposedShape::min_vertex(size_t idx) const
+{
+    if (!m_reference_vertex_valid) {
+        reference_vertex();
+    }
+
+    return m_mins[idx];
+}
+
+Vec2crd DecomposedShape::centroid() const
+{
+    constexpr double area_sc = scaled<double>(1.) * scaled(1.);
+
+    if (!m_centroid_valid) {
+        double total_area = 0.0;
+        Vec2d cntr = Vec2d::Zero();
+
+        for (const Polygon& poly : transformed_outline()) {
+            double parea = poly.area() / area_sc;
+            Vec2d pcntr = unscaled(poly.centroid());
+            total_area += parea;
+            cntr += pcntr * parea;
+        }
+
+        cntr /= total_area;
+        m_centroid = scaled(cntr);
+        m_centroid_valid = true;
+    }
+
+    return m_centroid;
+}
+
+DecomposedShape decompose(const ExPolygons &shape)
+{
+    return DecomposedShape{convex_decomposition_tess(shape)};
+}
+
+DecomposedShape decompose(const Polygon &shape)
+{
+    Polygons convex_shapes;
+
+    bool is_convex = polygon_is_convex(shape);
+    if (is_convex) {
+        convex_shapes.emplace_back(shape);
+    } else {
+        convex_shapes = convex_decomposition_tess(shape);
+    }
+
+    return DecomposedShape{std::move(convex_shapes)};
+}
+
+ArrangeItem::ArrangeItem(const ExPolygons &shape)
+    : m_shape{decompose(shape)}, m_envelope{&m_shape}
+{}
+
+ArrangeItem::ArrangeItem(Polygon shape)
+    : m_shape{decompose(shape)}, m_envelope{&m_shape}
+{}
+
+ArrangeItem::ArrangeItem(const ArrangeItem &other)
+{
+    this->operator= (other);
+}
+
+ArrangeItem::ArrangeItem(ArrangeItem &&other) noexcept
+{
+    this->operator=(std::move(other));
+}
+
+ArrangeItem &ArrangeItem::operator=(const ArrangeItem &other)
+{
+    m_shape = other.m_shape;
+    m_datastore = other.m_datastore;
+    m_bed_idx = other.m_bed_idx;
+    m_priority = other.m_priority;
+
+    if (other.m_envelope.get() == &other.m_shape)
+        m_envelope = &m_shape;
+    else
+        m_envelope = std::make_unique<DecomposedShape>(other.envelope());
+
+    return *this;
+}
+
+void ArrangeItem::set_shape(DecomposedShape shape)
+{
+    m_shape = std::move(shape);
+    m_envelope = &m_shape;
+}
+
+void ArrangeItem::set_envelope(DecomposedShape envelope)
+{
+    m_envelope = std::make_unique<DecomposedShape>(std::move(envelope));
+
+    // Initial synch of transformations of envelope and shape.
+    // They need to be in synch all the time
+    m_envelope->translation(m_shape.translation());
+    m_envelope->rotation(m_shape.rotation());
+}
+
+ArrangeItem &ArrangeItem::operator=(ArrangeItem &&other) noexcept
+{
+    m_shape = std::move(other.m_shape);
+    m_datastore = std::move(other.m_datastore);
+    m_bed_idx = other.m_bed_idx;
+    m_priority = other.m_priority;
+
+    if (other.m_envelope.get() == &other.m_shape)
+        m_envelope = &m_shape;
+    else
+        m_envelope = std::move(other.m_envelope);
+
+    return *this;
+}
+
+template struct ImbueableItemTraits_<ArrangeItem>;
+template class  ArrangeableToItemConverter<ArrangeItem>;
+template struct ArrangeTask<ArrangeItem>;
+template struct FillBedTask<ArrangeItem>;
+template struct MultiplySelectionTask<ArrangeItem>;
+template class  Arranger<ArrangeItem>;
+
+}} // namespace Slic3r::arr2

src/libslic3r/Arrange/Items/ArrangeItem.hpp

@@ -0,0 +1,480 @@
+#ifndef ARRANGEITEM_HPP
+#define ARRANGEITEM_HPP
+
+#include <optional>
+#include <boost/variant.hpp>
+
+#include "libslic3r/ExPolygon.hpp"
+#include "libslic3r/BoundingBox.hpp"
+#include "libslic3r/AnyPtr.hpp"
+
+#include "libslic3r/Arrange/Core/PackingContext.hpp"
+#include "libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/NFP/NFP.hpp"
+
+#include "libslic3r/Arrange/Items/MutableItemTraits.hpp"
+
+#include "libslic3r/Arrange/Arrange.hpp"
+#include "libslic3r/Arrange/Tasks/ArrangeTask.hpp"
+#include "libslic3r/Arrange/Tasks/FillBedTask.hpp"
+#include "libslic3r/Arrange/Tasks/MultiplySelectionTask.hpp"
+
+#include "libslic3r/Arrange/Items/ArbitraryDataStore.hpp"
+
+#include <libslic3r/ClipperUtils.hpp>
+
+namespace Slic3r { namespace arr2 {
+
+inline bool check_polygons_are_convex(const Polygons &pp) {
+    return std::all_of(pp.begin(), pp.end(), [](const Polygon &p) {
+        return polygon_is_convex(p);
+    });
+}
+
+// A class that stores a set of polygons that are garanteed to be all convex.
+// They collectively represent a decomposition of a more complex shape into
+// its convex part. Note that this class only stores the result of the decomp,
+// does not do the job itself. In debug mode, an explicit check is done for
+// each component to be convex.
+//
+// Additionally class stores a translation vector and a rotation angle for the
+// stored polygon, plus additional privitives that are all cached cached after
+// appying a the transformations. The caching is not thread safe!
+class DecomposedShape
+{
+    Polygons m_shape;
+
+    Vec2crd m_translation{0, 0}; // The translation of the poly
+    double  m_rotation{0.0};     // The rotation of the poly in radians
+
+    mutable Polygons m_transformed_outline;
+    mutable bool     m_transformed_outline_valid = false;
+
+    mutable Point              m_reference_vertex;
+    mutable std::vector<Point> m_refs;
+    mutable std::vector<Point> m_mins;
+    mutable bool               m_reference_vertex_valid = false;
+
+    mutable Point m_centroid;
+    mutable bool  m_centroid_valid = false;
+
+    mutable Polygon m_convex_hull;
+    mutable BoundingBox m_bounding_box;
+    mutable double  m_area = 0;
+
+public:
+    DecomposedShape() = default;
+
+    explicit DecomposedShape(Polygon sh)
+    {
+        m_shape.emplace_back(std::move(sh));
+        assert(check_polygons_are_convex(m_shape));
+    }
+
+    explicit DecomposedShape(std::initializer_list<Point> pts)
+        : DecomposedShape(Polygon{pts})
+    {}
+
+    explicit DecomposedShape(Polygons sh) : m_shape{std::move(sh)}
+    {
+        assert(check_polygons_are_convex(m_shape));
+    }
+
+    const Polygons &contours() const { return m_shape; }
+
+    const Vec2crd &translation() const { return m_translation; }
+    double         rotation() const { return m_rotation; }
+
+    void translation(const Vec2crd &v)
+    {
+        m_translation               = v;
+        m_transformed_outline_valid = false;
+        m_reference_vertex_valid    = false;
+        m_centroid_valid            = false;
+    }
+
+    void rotation(double v)
+    {
+        m_rotation                  = v;
+        m_transformed_outline_valid = false;
+        m_reference_vertex_valid    = false;
+        m_centroid_valid            = false;
+    }
+
+    const Polygons &transformed_outline() const;
+    const Polygon  &convex_hull() const;
+    const BoundingBox &bounding_box() const;
+
+    // The cached reference vertex in the context of NFP creation. Always
+    // refers to the leftmost upper vertex.
+    const Vec2crd  &reference_vertex() const;
+    const Vec2crd  &reference_vertex(size_t idx) const;
+
+    // Also for NFP calculations, the rightmost lowest vertex of the shape.
+    const Vec2crd  &min_vertex(size_t idx) const;
+
+    double area_unscaled() const
+    {
+        // update cache
+        transformed_outline();
+
+        return m_area;
+    }
+
+    Vec2crd centroid() const;
+};
+
+DecomposedShape decompose(const ExPolygons &polys);
+DecomposedShape decompose(const Polygon &p);
+
+class ArrangeItem
+{
+private:
+    DecomposedShape m_shape;            // Shape of item when it's not moving
+    AnyPtr<DecomposedShape> m_envelope; // Possibly different shape when packed
+
+    ArbitraryDataStore m_datastore;
+
+    int m_bed_idx{Unarranged}; // To which logical bed does this item belong
+    int m_priority{0};         // For sorting
+
+public:
+    ArrangeItem() = default;
+
+    explicit ArrangeItem(DecomposedShape shape)
+        : m_shape(std::move(shape)), m_envelope{&m_shape}
+    {}
+
+    explicit ArrangeItem(DecomposedShape shape, DecomposedShape envelope)
+        : m_shape(std::move(shape))
+        , m_envelope{std::make_unique<DecomposedShape>(std::move(envelope))}
+    {}
+
+    explicit ArrangeItem(const ExPolygons &shape);
+    explicit ArrangeItem(Polygon shape);
+    explicit ArrangeItem(std::initializer_list<Point> pts)
+        : ArrangeItem(Polygon{pts})
+    {}
+
+    ArrangeItem(const ArrangeItem &);
+    ArrangeItem(ArrangeItem &&) noexcept;
+    ArrangeItem & operator=(const ArrangeItem &);
+    ArrangeItem & operator=(ArrangeItem &&) noexcept;
+
+    int bed_idx() const { return m_bed_idx; }
+    int priority() const { return m_priority; }
+
+    void bed_idx(int v) { m_bed_idx = v; }
+    void priority(int v) { m_priority = v; }
+
+    const ArbitraryDataStore &datastore() const { return m_datastore; }
+    ArbitraryDataStore &datastore() { return m_datastore; }
+
+    const DecomposedShape & shape() const { return m_shape; }
+    void set_shape(DecomposedShape shape);
+
+    const DecomposedShape & envelope() const { return *m_envelope; }
+    void set_envelope(DecomposedShape envelope);
+
+    const Vec2crd &translation() const { return m_shape.translation(); }
+    double         rotation() const { return m_shape.rotation(); }
+
+    void translation(const Vec2crd &v)
+    {
+        m_shape.translation(v);
+        m_envelope->translation(v);
+    }
+
+    void rotation(double v)
+    {
+        m_shape.rotation(v);
+        m_envelope->rotation(v);
+    }
+
+    void update_caches() const
+    {
+        m_shape.reference_vertex();
+        m_envelope->reference_vertex();
+        m_shape.centroid();
+        m_envelope->centroid();
+    }
+};
+
+template<> struct ArrangeItemTraits_<ArrangeItem>
+{
+    static const Vec2crd &get_translation(const ArrangeItem &itm)
+    {
+        return itm.translation();
+    }
+
+    static double get_rotation(const ArrangeItem &itm)
+    {
+        return itm.rotation();
+    }
+
+    static int get_bed_index(const ArrangeItem &itm)
+    {
+        return itm.bed_idx();
+    }
+
+    static int get_priority(const ArrangeItem &itm)
+    {
+        return itm.priority();
+    }
+
+    // Setters:
+
+    static void set_translation(ArrangeItem &itm, const Vec2crd &v)
+    {
+        itm.translation(v);
+    }
+
+    static void set_rotation(ArrangeItem &itm, double v)
+    {
+        itm.rotation(v);
+    }
+
+    static void set_bed_index(ArrangeItem &itm, int v)
+    {
+        itm.bed_idx(v);
+    }
+};
+
+// Some items can be containers of arbitrary data stored under string keys.
+template<> struct DataStoreTraits_<ArrangeItem>
+{
+    static constexpr bool Implemented = true;
+
+    template<class T>
+    static const T *get(const ArrangeItem &itm, const std::string &key)
+    {
+        return itm.datastore().get<T>(key);
+    }
+
+    // Same as above just not const.
+    template<class T>
+    static T *get(ArrangeItem &itm, const std::string &key)
+    {
+        return itm.datastore().get<T>(key);
+    }
+
+    static bool has_key(const ArrangeItem &itm, const std::string &key)
+    {
+        return itm.datastore().has_key(key);
+    }
+};
+
+template<> struct WritableDataStoreTraits_<ArrangeItem>
+{
+    static constexpr bool Implemented = true;
+
+    template<class T>
+    static void set(ArrangeItem &itm,
+                    const std::string &key,
+                    T &&data)
+    {
+        itm.datastore().add(key, std::forward<T>(data));
+    }
+};
+
+template<class FixedIt, class StopCond = DefaultStopCondition>
+static Polygons calculate_nfp_unnormalized(const ArrangeItem    &item,
+                                           const Range<FixedIt> &fixed_items,
+                                           StopCond &&stop_cond = {})
+{
+    size_t cap = 0;
+
+    for (const ArrangeItem &fixitem : fixed_items) {
+        const Polygons &outlines = fixitem.shape().transformed_outline();
+        cap += outlines.size();
+    }
+
+    const Polygons &item_outlines = item.envelope().transformed_outline();
+
+    auto nfps = reserve_polygons(cap * item_outlines.size());
+
+    Vec2crd ref_whole = item.envelope().reference_vertex();
+    Polygon subnfp;
+
+    for (const ArrangeItem &fixed : fixed_items) {
+        // fixed_polys should already be a set of strictly convex polygons,
+        // as ArrangeItem stores convex-decomposed polygons
+        const Polygons & fixed_polys = fixed.shape().transformed_outline();
+
+        for (const Polygon &fixed_poly : fixed_polys) {
+            Point max_fixed = Slic3r::reference_vertex(fixed_poly);
+            for (size_t mi = 0; mi < item_outlines.size(); ++mi) {
+                const Polygon &movable = item_outlines[mi];
+                const Vec2crd &mref = item.envelope().reference_vertex(mi);
+                subnfp = nfp_convex_convex_legacy(fixed_poly, movable);
+
+                Vec2crd min_movable = item.envelope().min_vertex(mi);
+
+                Vec2crd dtouch = max_fixed - min_movable;
+                Vec2crd top_other = mref + dtouch;
+                Vec2crd max_nfp = Slic3r::reference_vertex(subnfp);
+                auto dnfp = top_other - max_nfp;
+
+                auto d = ref_whole - mref + dnfp;
+                subnfp.translate(d);
+                nfps.emplace_back(subnfp);
+            }
+
+            if (stop_cond())
+                break;
+
+            nfps = union_(nfps);
+        }
+
+        if (stop_cond()) {
+            nfps.clear();
+            break;
+        }
+    }
+
+    return nfps;
+}
+
+template<> struct NFPArrangeItemTraits_<ArrangeItem> {
+    template<class Context, class Bed, class StopCond>
+    static ExPolygons calculate_nfp(const ArrangeItem &item,
+                                    const Context &packing_context,
+                                    const Bed &bed,
+                                    StopCond &&stopcond)
+    {
+        auto static_items = all_items_range(packing_context);
+        Polygons nfps = arr2::calculate_nfp_unnormalized(item, static_items, stopcond);
+
+        ExPolygons nfp_ex;
+
+        if (!stopcond()) {
+            if constexpr (!std::is_convertible_v<Bed, InfiniteBed>) {
+                ExPolygons ifpbed = ifp_convex(bed, item.envelope().convex_hull());
+                nfp_ex = diff_ex(ifpbed, nfps);
+            } else {
+                nfp_ex = union_ex(nfps);
+            }
+        }
+
+        item.update_caches();
+
+        return nfp_ex;
+    }
+
+    static const Vec2crd& reference_vertex(const ArrangeItem &item)
+    {
+        return item.envelope().reference_vertex();
+    }
+
+    static BoundingBox envelope_bounding_box(const ArrangeItem &itm)
+    {
+        return itm.envelope().bounding_box();
+    }
+
+    static BoundingBox fixed_bounding_box(const ArrangeItem &itm)
+    {
+        return itm.shape().bounding_box();
+    }
+
+    static double envelope_area(const ArrangeItem &itm)
+    {
+        return itm.envelope().area_unscaled() * scaled<double>(1.) *
+               scaled<double>(1.);
+    }
+
+    static double fixed_area(const ArrangeItem &itm)
+    {
+        return itm.shape().area_unscaled() * scaled<double>(1.) *
+               scaled<double>(1.);
+    }
+
+    static const Polygons & envelope_outline(const ArrangeItem &itm)
+    {
+        return itm.envelope().transformed_outline();
+    }
+
+    static const Polygons & fixed_outline(const ArrangeItem &itm)
+    {
+        return itm.shape().transformed_outline();
+    }
+
+    static const Polygon & envelope_convex_hull(const ArrangeItem &itm)
+    {
+        return itm.envelope().convex_hull();
+    }
+
+    static const Polygon & fixed_convex_hull(const ArrangeItem &itm)
+    {
+        return itm.shape().convex_hull();
+    }
+
+    static const std::vector<double>& allowed_rotations(const ArrangeItem &itm)
+    {
+        static const std::vector<double> ret_zero = {0.};
+
+        const std::vector<double> * ret_ptr = &ret_zero;
+
+        auto rots = get_data<std::vector<double>>(itm, "rotations");
+        if (rots) {
+            ret_ptr = rots;
+        }
+
+        return *ret_ptr;
+    }
+
+    static Vec2crd fixed_centroid(const ArrangeItem &itm)
+    {
+        return itm.shape().centroid();
+    }
+
+    static Vec2crd envelope_centroid(const ArrangeItem &itm)
+    {
+        return itm.envelope().centroid();
+    }
+};
+
+template<> struct IsMutableItem_<ArrangeItem>: public std::true_type {};
+
+template<>
+struct MutableItemTraits_<ArrangeItem> {
+
+    static void set_priority(ArrangeItem &itm, int p) { itm.priority(p); }
+    static void set_convex_shape(ArrangeItem &itm, const Polygon &shape)
+    {
+        itm.set_shape(DecomposedShape{shape});
+    }
+    static void set_shape(ArrangeItem &itm, const ExPolygons &shape)
+    {
+        itm.set_shape(decompose(shape));
+    }
+    static void set_convex_envelope(ArrangeItem &itm, const Polygon &envelope)
+    {
+        itm.set_envelope(DecomposedShape{envelope});
+    }
+    static void set_envelope(ArrangeItem &itm, const ExPolygons &envelope)
+    {
+        itm.set_envelope(decompose(envelope));
+    }
+
+    template<class T>
+    static void set_arbitrary_data(ArrangeItem &itm, const std::string &key, T &&data)
+    {
+        set_data(itm, key, std::forward<T>(data));
+    }
+
+    static void set_allowed_rotations(ArrangeItem &itm, const std::vector<double> &rotations)
+    {
+        set_data(itm, "rotations", rotations);
+    }
+};
+
+extern template struct ImbueableItemTraits_<ArrangeItem>;
+extern template class  ArrangeableToItemConverter<ArrangeItem>;
+extern template struct ArrangeTask<ArrangeItem>;
+extern template struct FillBedTask<ArrangeItem>;
+extern template struct MultiplySelectionTask<ArrangeItem>;
+extern template class  Arranger<ArrangeItem>;
+
+}} // namespace Slic3r::arr2
+
+#endif // ARRANGEITEM_HPP

src/libslic3r/Arrange/Items/MutableItemTraits.hpp

@@ -0,0 +1,136 @@
+#ifndef MutableItemTraits_HPP
+#define MutableItemTraits_HPP
+
+#include "libslic3r/Arrange/Core/ArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/DataStoreTraits.hpp"
+
+#include "libslic3r/ExPolygon.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+template<class Itm> struct IsMutableItem_ : public std::false_type
+{};
+
+// Using this interface to set up any arrange item. Provides default
+// implementation but it needs to be explicitly switched on with
+// IsMutableItem_ or completely reimplement a specialization.
+template<class Itm, class En = void> struct MutableItemTraits_
+{
+    static_assert(IsMutableItem_<Itm>::value, "Not a Writable item type!");
+
+    static void set_priority(Itm &itm, int p) { itm.set_priority(p); }
+
+    static void set_convex_shape(Itm &itm, const Polygon &shape)
+    {
+        itm.set_convex_shape(shape);
+    }
+
+    static void set_shape(Itm &itm, const ExPolygons &shape)
+    {
+        itm.set_shape(shape);
+    }
+
+    static void set_convex_envelope(Itm &itm, const Polygon &envelope)
+    {
+        itm.set_convex_envelope(envelope);
+    }
+
+    static void set_envelope(Itm &itm, const ExPolygons &envelope)
+    {
+        itm.set_envelope(envelope);
+    }
+
+    template<class T>
+    static void set_arbitrary_data(Itm &itm, const std::string &key, T &&data)
+    {
+        if constexpr (IsWritableDataStore<Itm>)
+            set_data(itm, key, std::forward<T>(data));
+    }
+
+    static void set_allowed_rotations(Itm                       &itm,
+                                      const std::vector<double> &rotations)
+    {
+        itm.set_allowed_rotations(rotations);
+    }
+};
+
+template<class T>
+using MutableItemTraits = MutableItemTraits_<StripCVRef<T>>;
+
+template<class T> constexpr bool IsMutableItem = IsMutableItem_<T>::value;
+template<class T, class TT = T>
+using MutableItemOnly = std::enable_if_t<IsMutableItem<T>, TT>;
+
+template<class Itm> void set_priority(Itm &itm, int p)
+{
+    MutableItemTraits<Itm>::set_priority(itm, p);
+}
+
+template<class Itm> void set_convex_shape(Itm &itm, const Polygon &shape)
+{
+    MutableItemTraits<Itm>::set_convex_shape(itm, shape);
+}
+
+template<class Itm> void set_shape(Itm &itm, const ExPolygons &shape)
+{
+    MutableItemTraits<Itm>::set_shape(itm, shape);
+}
+
+template<class Itm>
+void set_convex_envelope(Itm &itm, const Polygon &envelope)
+{
+    MutableItemTraits<Itm>::set_convex_envelope(itm, envelope);
+}
+
+template<class Itm> void set_envelope(Itm &itm, const ExPolygons &envelope)
+{
+    MutableItemTraits<Itm>::set_envelope(itm, envelope);
+}
+
+template<class T, class Itm>
+void set_arbitrary_data(Itm &itm, const std::string &key, T &&data)
+{
+    MutableItemTraits<Itm>::set_arbitrary_data(itm, key, std::forward<T>(data));
+}
+
+template<class Itm>
+void set_allowed_rotations(Itm &itm, const std::vector<double> &rotations)
+{
+    MutableItemTraits<Itm>::set_allowed_rotations(itm, rotations);
+}
+
+template<class ArrItem> int raise_priority(ArrItem &itm)
+{
+    int ret = get_priority(itm) + 1;
+    set_priority(itm, ret);
+
+    return ret;
+}
+
+template<class ArrItem> int reduce_priority(ArrItem &itm)
+{
+    int ret = get_priority(itm) - 1;
+    set_priority(itm, ret);
+
+    return ret;
+}
+
+template<class It> int lowest_priority(const Range<It> &item_range)
+{
+    auto minp_it = std::min_element(item_range.begin(),
+                                    item_range.end(),
+                                    [](auto &itm1, auto &itm2) {
+                                        return get_priority(itm1) <
+                                               get_priority(itm2);
+                                    });
+
+    int min_priority = 0;
+    if (minp_it != item_range.end())
+        min_priority = get_priority(*minp_it);
+
+    return min_priority;
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // MutableItemTraits_HPP

src/libslic3r/Arrange/Items/SimpleArrangeItem.cpp

@@ -0,0 +1,24 @@
+#include "SimpleArrangeItem.hpp"
+#include "libslic3r/Arrange/ArrangeImpl.hpp"
+#include "libslic3r/Arrange/Tasks/ArrangeTaskImpl.hpp"
+#include "libslic3r/Arrange/Tasks/FillBedTaskImpl.hpp"
+#include "libslic3r/Arrange/Tasks/MultiplySelectionTaskImpl.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+Polygon SimpleArrangeItem::outline() const
+{
+    Polygon ret = shape();
+    ret.rotate(m_rotation);
+    ret.translate(m_translation);
+
+    return ret;
+}
+
+template class  ArrangeableToItemConverter<SimpleArrangeItem>;
+template struct ArrangeTask<SimpleArrangeItem>;
+template struct FillBedTask<SimpleArrangeItem>;
+template struct MultiplySelectionTask<SimpleArrangeItem>;
+template class  Arranger<SimpleArrangeItem>;
+
+}} // namespace Slic3r::arr2

src/libslic3r/Arrange/Items/SimpleArrangeItem.hpp

@@ -0,0 +1,218 @@
+#ifndef SIMPLEARRANGEITEM_HPP
+#define SIMPLEARRANGEITEM_HPP
+
+#include "libslic3r/Arrange/Core/PackingContext.hpp"
+
+#include "libslic3r/Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+#include "libslic3r/Arrange/Core/NFP/NFP.hpp"
+
+#include "libslic3r/Arrange/Arrange.hpp"
+#include "libslic3r/Arrange/Tasks/ArrangeTask.hpp"
+#include "libslic3r/Arrange/Tasks/FillBedTask.hpp"
+#include "libslic3r/Arrange/Tasks/MultiplySelectionTask.hpp"
+
+#include "libslic3r/Polygon.hpp"
+#include "libslic3r/Geometry/ConvexHull.hpp"
+
+#include "MutableItemTraits.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+class SimpleArrangeItem {
+    Polygon m_shape;
+
+    Vec2crd m_translation = Vec2crd::Zero();
+    double  m_rotation = 0.;
+    int     m_priority = 0;
+    int     m_bed_idx = Unarranged;
+
+    std::vector<double> m_allowed_rotations = {0.};
+    ObjectID m_obj_id;
+
+public:
+    explicit SimpleArrangeItem(Polygon chull = {}): m_shape{std::move(chull)} {}
+
+    void set_shape(Polygon chull) { m_shape = std::move(chull); }
+
+    const Vec2crd& get_translation() const noexcept { return m_translation; }
+    double get_rotation() const noexcept { return m_rotation; }
+    int get_priority() const noexcept { return m_priority; }
+    int get_bed_index() const noexcept { return m_bed_idx; }
+
+    void set_translation(const Vec2crd &v) { m_translation = v; }
+    void set_rotation(double v) noexcept { m_rotation = v; }
+    void set_priority(int v) noexcept { m_priority = v; }
+    void set_bed_index(int v) noexcept { m_bed_idx = v; }
+
+    const Polygon &shape() const { return m_shape; }
+    Polygon outline() const;
+
+    const auto &allowed_rotations() const noexcept
+    {
+        return m_allowed_rotations;
+    }
+
+    void set_allowed_rotations(std::vector<double> rots)
+    {
+        m_allowed_rotations = std::move(rots);
+    }
+
+    void set_object_id(const ObjectID &id) noexcept { m_obj_id = id; }
+    const ObjectID & get_object_id() const noexcept { return m_obj_id; }
+};
+
+template<> struct NFPArrangeItemTraits_<SimpleArrangeItem>
+{
+    template<class Context, class Bed, class StopCond>
+    static ExPolygons calculate_nfp(const SimpleArrangeItem &item,
+                                    const Context &packing_context,
+                                    const Bed &bed,
+                                    StopCond &&stop_cond)
+    {
+        auto fixed_items = all_items_range(packing_context);
+        auto nfps = reserve_polygons(fixed_items.size());
+        for (const SimpleArrangeItem &fixed_part : fixed_items) {
+            Polygon subnfp = nfp_convex_convex_legacy(fixed_part.outline(),
+                                                      item.outline());
+            nfps.emplace_back(subnfp);
+
+
+            if (stop_cond()) {
+                nfps.clear();
+                break;
+            }
+        }
+
+        ExPolygons nfp_ex;
+        if (!stop_cond()) {
+            if constexpr (!std::is_convertible_v<Bed, InfiniteBed>) {
+                ExPolygons ifpbed = ifp_convex(bed, item.outline());
+                nfp_ex = diff_ex(ifpbed, nfps);
+            } else {
+                nfp_ex = union_ex(nfps);
+            }
+        }
+
+        return nfp_ex;
+    }
+
+    static Vec2crd reference_vertex(const SimpleArrangeItem &item)
+    {
+        return Slic3r::reference_vertex(item.outline());
+    }
+
+    static BoundingBox envelope_bounding_box(const SimpleArrangeItem &itm)
+    {
+        return get_extents(itm.outline());
+    }
+
+    static BoundingBox fixed_bounding_box(const SimpleArrangeItem &itm)
+    {
+        return get_extents(itm.outline());
+    }
+
+    static Polygons envelope_outline(const SimpleArrangeItem &itm)
+    {
+        return {itm.outline()};
+    }
+
+    static Polygons fixed_outline(const SimpleArrangeItem &itm)
+    {
+        return {itm.outline()};
+    }
+
+    static Polygon envelope_convex_hull(const SimpleArrangeItem &itm)
+    {
+        return Geometry::convex_hull(itm.outline());
+    }
+
+    static Polygon fixed_convex_hull(const SimpleArrangeItem &itm)
+    {
+        return Geometry::convex_hull(itm.outline());
+    }
+
+    static double envelope_area(const SimpleArrangeItem &itm)
+    {
+        return itm.shape().area();
+    }
+
+    static double fixed_area(const SimpleArrangeItem &itm)
+    {
+        return itm.shape().area();
+    }
+
+    static const auto& allowed_rotations(const SimpleArrangeItem &itm) noexcept
+    {
+        return itm.allowed_rotations();
+    }
+
+    static Vec2crd fixed_centroid(const SimpleArrangeItem &itm) noexcept
+    {
+        return itm.outline().centroid();
+    }
+
+    static Vec2crd envelope_centroid(const SimpleArrangeItem &itm) noexcept
+    {
+        return itm.outline().centroid();
+    }
+};
+
+template<> struct IsMutableItem_<SimpleArrangeItem>: public std::true_type {};
+
+template<>
+struct MutableItemTraits_<SimpleArrangeItem> {
+
+    static void set_priority(SimpleArrangeItem &itm, int p) { itm.set_priority(p); }
+    static void set_convex_shape(SimpleArrangeItem &itm, const Polygon &shape)
+    {
+        itm.set_shape(shape);
+    }
+    static void set_shape(SimpleArrangeItem &itm, const ExPolygons &shape)
+    {
+        itm.set_shape(Geometry::convex_hull(shape));
+    }
+    static void set_convex_envelope(SimpleArrangeItem &itm, const Polygon &envelope)
+    {
+        itm.set_shape(envelope);
+    }
+    static void set_envelope(SimpleArrangeItem &itm, const ExPolygons &envelope)
+    {
+        itm.set_shape(Geometry::convex_hull(envelope));
+    }
+
+    template<class T>
+    static void set_data(SimpleArrangeItem &itm, const std::string &key, T &&data)
+    {}
+
+    static void set_allowed_rotations(SimpleArrangeItem &itm, const std::vector<double> &rotations)
+    {
+        itm.set_allowed_rotations(rotations);
+    }
+};
+
+template<> struct ImbueableItemTraits_<SimpleArrangeItem>
+{
+    static void imbue_id(SimpleArrangeItem &itm, const ObjectID &id)
+    {
+        itm.set_object_id(id);
+    }
+
+    static std::optional<ObjectID> retrieve_id(const SimpleArrangeItem &itm)
+    {
+        std::optional<ObjectID> ret;
+        if (itm.get_object_id().valid())
+            ret = itm.get_object_id();
+
+        return ret;
+    }
+};
+
+extern template class  ArrangeableToItemConverter<SimpleArrangeItem>;
+extern template struct ArrangeTask<SimpleArrangeItem>;
+extern template struct FillBedTask<SimpleArrangeItem>;
+extern template struct MultiplySelectionTask<SimpleArrangeItem>;
+extern template class  Arranger<SimpleArrangeItem>;
+
+}} // namespace Slic3r::arr2
+
+#endif // SIMPLEARRANGEITEM_HPP

src/libslic3r/Arrange/Items/TrafoOnlyArrangeItem.hpp

@@ -0,0 +1,79 @@
+#ifndef TRAFOONLYARRANGEITEM_HPP
+#define TRAFOONLYARRANGEITEM_HPP
+
+#include "libslic3r/Arrange/Core/ArrangeItemTraits.hpp"
+
+#include "libslic3r/Arrange/Items/ArbitraryDataStore.hpp"
+#include "libslic3r/Arrange/Items/MutableItemTraits.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+class TrafoOnlyArrangeItem {
+    int m_bed_idx = Unarranged;
+    int m_priority = 0;
+    Vec2crd m_translation = Vec2crd::Zero();
+    double  m_rotation = 0.;
+
+    ArbitraryDataStore m_datastore;
+
+public:
+    TrafoOnlyArrangeItem() = default;
+
+    template<class ArrItm>
+    explicit TrafoOnlyArrangeItem(const ArrItm &other)
+        : m_bed_idx{arr2::get_bed_index(other)},
+          m_priority{arr2::get_priority(other)},
+          m_translation(arr2::get_translation(other)),
+          m_rotation{arr2::get_rotation(other)}
+    {}
+
+    const Vec2crd& get_translation() const noexcept { return m_translation; }
+    double get_rotation() const noexcept { return m_rotation; }
+    int get_bed_index() const noexcept { return m_bed_idx; }
+    int get_priority() const noexcept { return m_priority; }
+
+    const ArbitraryDataStore &datastore() const noexcept { return m_datastore; }
+    ArbitraryDataStore &datastore() { return m_datastore; }
+};
+
+template<> struct DataStoreTraits_<TrafoOnlyArrangeItem>
+{
+    static constexpr bool Implemented = true;
+
+    template<class T>
+    static const T *get(const TrafoOnlyArrangeItem &itm, const std::string &key)
+    {
+        return itm.datastore().get<T>(key);
+    }
+
+    template<class T>
+    static T *get(TrafoOnlyArrangeItem &itm, const std::string &key)
+    {
+        return itm.datastore().get<T>(key);
+    }
+
+    static bool has_key(const TrafoOnlyArrangeItem &itm, const std::string &key)
+    {
+        return itm.datastore().has_key(key);
+    }
+};
+
+template<> struct IsMutableItem_<TrafoOnlyArrangeItem>: public std::true_type {};
+
+template<> struct WritableDataStoreTraits_<TrafoOnlyArrangeItem>
+{
+    static constexpr bool Implemented = true;
+
+    template<class T>
+    static void set(TrafoOnlyArrangeItem &itm,
+                    const std::string &key,
+                    T &&data)
+    {
+        set_data(itm.datastore(), key, std::forward<T>(data));
+    }
+};
+
+} // namespace arr2
+} // namespace Slic3r
+
+#endif // TRAFOONLYARRANGEITEM_HPP

src/libslic3r/Arrange/Scene.cpp

@@ -0,0 +1,64 @@
+#include "Scene.hpp"
+
+#include "Items/ArrangeItem.hpp"
+
+#include "Tasks/ArrangeTask.hpp"
+#include "Tasks/FillBedTask.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+std::vector<ObjectID> Scene::selected_ids() const
+{
+    auto items = reserve_vector<ObjectID>(model().arrangeable_count());
+
+    model().for_each_arrangeable([ &items](auto &arrbl) mutable {
+        if (arrbl.is_selected())
+            items.emplace_back(arrbl.id());
+    });
+
+    return items;
+}
+
+using DefaultArrangeItem = ArrangeItem;
+
+std::unique_ptr<ArrangeTaskBase> ArrangeTaskBase::create(Tasks task_type, const Scene &sc)
+{
+    std::unique_ptr<ArrangeTaskBase> ret;
+    switch(task_type) {
+    case Tasks::Arrange:
+        ret = ArrangeTask<ArrangeItem>::create(sc);
+        break;
+    case Tasks::FillBed:
+        ret = FillBedTask<ArrangeItem>::create(sc);
+        break;
+    default:
+        ;
+    }
+
+    return ret;
+}
+
+std::set<ObjectID> selected_geometry_ids(const Scene &sc)
+{
+    std::set<ObjectID> result;
+
+    std::vector<ObjectID> selected_ids = sc.selected_ids();
+    for (const ObjectID &id : selected_ids) {
+        sc.model().visit_arrangeable(id, [&result](const Arrangeable &arrbl) {
+            auto id = arrbl.geometry_id();
+            if (id.valid())
+                result.insert(arrbl.geometry_id());
+        });
+    }
+
+    return result;
+}
+
+bool arrange(Scene &scene, ArrangeTaskCtl &ctl)
+{
+    auto task = ArrangeTaskBase::create(Tasks::Arrange, scene);
+    auto result = task->process(ctl);
+    return result->apply_on(scene.model());
+}
+
+}} // namespace Slic3r::arr2

src/libslic3r/Arrange/Scene.hpp

@@ -0,0 +1,401 @@
+#ifndef ARR2_SCENE_HPP
+#define ARR2_SCENE_HPP
+
+#include <any>
+#include <string_view>
+
+#include "libslic3r/ObjectID.hpp"
+#include "libslic3r/AnyPtr.hpp"
+#include "libslic3r/Arrange/ArrangeSettingsView.hpp"
+#include "libslic3r/Arrange/SegmentedRectangleBed.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+// This module contains all the necessary high level interfaces for
+// arrangement. No dependency on the rest of libslic3r is intoduced here. (No
+// Model, ModelObject, etc...) except for ObjectID.
+
+
+// An interface that allows to store arbitrary data (std::any) under a specific
+// key in an object implementing the interface. This is later used to pass
+// arbitrary parameters from any arrangeable object down to the arrangement core.
+class AnyWritable
+{
+public:
+    virtual ~AnyWritable() = default;
+
+    virtual void write(std::string_view key, std::any d) = 0;
+};
+
+// The interface that captures the objects which are actually moved around.
+// Implementations must provide means to extract the 2D outline that is used
+// by the arrangement core.
+class Arrangeable
+{
+public:
+    virtual ~Arrangeable() = default;
+
+    // ID is implementation specific, must uniquely identify an Arrangeable
+    // object.
+    virtual ObjectID id() const = 0;
+
+    // This is different than id(), and identifies an underlying group into
+    // which the Arrangeable belongs. Can be used to group arrangeables sharing
+    // the same outline.
+    virtual ObjectID   geometry_id() const    = 0;
+
+    // Outline extraction can be a demanding operation, so there is a separate
+    // method the extract the full outline of an object and the convex hull only
+    // It will depend on the arrangement config to choose which one is called.
+    // convex_outline might be considerably faster than calling full_outline()
+    // and then calculating the convex hull from that.
+    virtual ExPolygons full_outline() const   = 0;
+    virtual Polygon    convex_outline() const = 0;
+
+    // Envelope is the boundary that an arrangeble object might have which
+    // is used when the object is being placed or moved around. Once it is
+    // placed, the outline (convex or full) will be used to determine the
+    // boundaries instead of the envelope. This concept can be used to
+    // implement arranging objects with support structures that can overlap,
+    // but never touch the actual object. In this case, full envelope would
+    // return the silhouette of the object with supports (pad, brim, etc...) and
+    // outline would be the actual object boundary.
+    virtual ExPolygons full_envelope() const { return {}; }
+    virtual Polygon    convex_envelope() const { return {}; }
+
+    // Write the transformations determined by the arrangement into the object
+    virtual void transform(const Vec2d &transl, double rot) = 0;
+
+    // An arrangeable can be printable or unprintable, they should not be on
+    // the same bed. (See arrange tasks)
+    virtual bool is_printable() const { return true; }
+
+    // An arrangeable can be selected or not, this will determine if treated
+    // as static objects or movable ones.
+    virtual bool is_selected() const { return true; }
+
+    // Determines the order in which the objects are arranged. Higher priority
+    // objects are arranged first.
+    virtual int  priority() const { return 0; }
+
+    // Any implementation specific properties can be passed to the arrangement
+    // core by overriding this method. This implies that the specific Arranger
+    // will be able to interpret these properties. An example usage is to mark
+    // special objects (like a wipe tower)
+    virtual void imbue_data(AnyWritable &datastore) const {}
+
+    // for convinience to pass an AnyWritable created in the same expression
+    // as the method call
+    void imbue_data(AnyWritable &&datastore) const { imbue_data(datastore); }
+
+    // An Arrangeable might reside on a logical bed instead of the real one
+    // in case that the arrangement can not fit it onto the real bed. Handling
+    // of logical beds is also implementation specific and are specified with
+    // the next two methods:
+
+    // Returns the bed index on which the given Arrangeable is sitting.
+    virtual int get_bed_index() const = 0;
+
+    // Assign the Arrangeable to the given bed index. Note that this
+    // method can return false, indicating that the given bed is not available
+    // to be occupied.
+    virtual bool assign_bed(int bed_idx) = 0;
+};
+
+// Arrangeable objects are provided by an ArrangeableModel which is also able to
+// create new arrangeables given a prototype id to copy.
+class ArrangeableModel
+{
+public:
+    virtual ~ArrangeableModel() = default;
+
+    // Visit all arrangeable in this model and call the provided visitor
+    virtual void for_each_arrangeable(std::function<void(Arrangeable &)>) = 0;
+    virtual void for_each_arrangeable(std::function<void(const Arrangeable&)>) const = 0;
+
+    // Visit a specific arrangeable identified by it's id
+    virtual void visit_arrangeable(const ObjectID &id, std::function<void(const Arrangeable &)>) const = 0;
+    virtual void visit_arrangeable(const ObjectID &id, std::function<void(Arrangeable &)>) = 0;
+
+    // Add a new arrangeable which is a copy of the one matching prototype_id
+    // Return the new object id or an invalid id if the new object was not
+    // created.
+    virtual ObjectID add_arrangeable(const ObjectID &prototype_id) = 0;
+
+    size_t arrangeable_count() const
+    {
+        size_t cnt = 0;
+        for_each_arrangeable([&cnt](auto &) { ++cnt; });
+
+        return cnt;
+    }
+};
+
+// The special bed type used by XL printers
+using XLBed = SegmentedRectangleBed<std::integral_constant<size_t, 4>,
+                                    std::integral_constant<size_t, 4>>;
+
+// ExtendedBed is a variant type holding all bed types supported by the
+// arrange core and the additional XLBed
+
+template<class... Args> struct ExtendedBed_
+{
+    using Type =
+        boost::variant<XLBed, /* insert other types if needed*/ Args...>;
+};
+
+template<class... Args> struct ExtendedBed_<boost::variant<Args...>>
+{
+    using Type = boost::variant<XLBed, Args...>;
+};
+
+using ExtendedBed = typename ExtendedBed_<ArrangeBed>::Type;
+
+template<class BedFn> void visit_bed(BedFn &&fn, const ExtendedBed &bed)
+{
+    boost::apply_visitor(fn, bed);
+}
+
+template<class BedFn> void visit_bed(BedFn &&fn, ExtendedBed &bed)
+{
+    boost::apply_visitor(fn, bed);
+}
+
+inline BoundingBox bounding_box(const ExtendedBed &bed)
+{
+    BoundingBox bedbb;
+    visit_bed([&bedbb](auto &rawbed) { bedbb = bounding_box(rawbed); }, bed);
+
+    return bedbb;
+}
+
+class Scene;
+
+// SceneBuilderBase is intended for Scene construction. A simple constructor
+// is not enough here to capture all the possible ways of constructing a Scene.
+// Subclasses of SceneBuilderBase can add more domain specific methods and
+// overloads. An rvalue object of this class is handed over to the Scene
+// constructor which can then establish itself using the provided builder.
+
+// A little CRTP is used to implement fluent interface returning Subclass
+// references.
+template<class Subclass>
+class SceneBuilderBase
+{
+protected:
+    AnyPtr<ArrangeableModel> m_arrangeable_model;
+
+    AnyPtr<const ArrangeSettingsView> m_settings;
+
+    ExtendedBed m_bed = arr2::InfiniteBed{};
+
+    coord_t m_brims_offs = 0;
+    coord_t m_skirt_offs = 0;
+
+public:
+
+    virtual ~SceneBuilderBase() = default;
+
+    SceneBuilderBase() = default;
+    SceneBuilderBase(const SceneBuilderBase &) = delete;
+    SceneBuilderBase& operator=(const SceneBuilderBase &) = delete;
+    SceneBuilderBase(SceneBuilderBase &&) = default;
+    SceneBuilderBase& operator=(SceneBuilderBase &&) = default;
+
+    // All setters return an rvalue reference so that at the end, the
+    // build_scene method can be called fluently
+
+    Subclass &&set_arrange_settings(AnyPtr<const ArrangeSettingsView> settings)
+    {
+        m_settings = std::move(settings);
+        return std::move(static_cast<Subclass&>(*this));
+    }
+
+    Subclass &&set_arrange_settings(const ArrangeSettingsView &settings)
+    {
+        m_settings = std::make_unique<ArrangeSettings>(settings);
+        return std::move(static_cast<Subclass&>(*this));
+    }
+
+    Subclass &&set_bed(const Points &pts)
+    {
+        m_bed = arr2::to_arrange_bed(pts);
+        return std::move(static_cast<Subclass&>(*this));
+    }
+
+    Subclass && set_bed(const arr2::ArrangeBed &bed)
+    {
+        m_bed = bed;
+        return std::move(static_cast<Subclass&>(*this));
+    }
+
+    Subclass &&set_bed(const XLBed &bed)
+    {
+        m_bed = bed;
+        return std::move(static_cast<Subclass&>(*this));
+    }
+
+    Subclass &&set_arrangeable_model(AnyPtr<ArrangeableModel> model)
+    {
+        m_arrangeable_model = std::move(model);
+        return std::move(static_cast<Subclass&>(*this));
+    }
+
+    // Can only be called on an rvalue instance (hence the && at the end),
+    // the method will potentially move its content into sc
+    virtual void build_scene(Scene &sc) &&;
+};
+
+class BasicSceneBuilder: public SceneBuilderBase<BasicSceneBuilder> {};
+
+// The Scene class captures all data needed to do an arrangement.
+class Scene
+{
+    template <class Sub> friend class SceneBuilderBase;
+
+    // These fields always need to be initialized to valid objects after
+    // construction of Scene which is ensured by the SceneBuilder
+    AnyPtr<ArrangeableModel>                m_amodel;
+    AnyPtr<const ArrangeSettingsView>       m_settings;
+    ExtendedBed m_bed;
+
+public:
+    // Can only be built from an rvalue SceneBuilder, as it's content will
+    // potentially be moved to the constructed ArrangeScene object
+    template<class Sub>
+    explicit Scene(SceneBuilderBase<Sub> &&bld)
+    {
+        std::move(bld).build_scene(*this);
+    }
+
+    const ArrangeableModel &model() const noexcept { return *m_amodel; }
+    ArrangeableModel       &model() noexcept { return *m_amodel; }
+
+    const ArrangeSettingsView &settings() const noexcept { return *m_settings; }
+
+    template<class BedFn> void visit_bed(BedFn &&fn) const
+    {
+        arr2::visit_bed(fn, m_bed);
+    }
+
+    const ExtendedBed & bed() const { return m_bed; }
+
+    std::vector<ObjectID> selected_ids() const;
+};
+
+std::set<ObjectID> selected_geometry_ids(const Scene &sc);
+
+class EmptyArrangeableModel: public ArrangeableModel
+{
+public:
+    void for_each_arrangeable(std::function<void(Arrangeable &)>) override {}
+    void for_each_arrangeable(std::function<void(const Arrangeable&)>) const override {}
+    void visit_arrangeable(const ObjectID &id, std::function<void(const Arrangeable &)>) const override {}
+    void visit_arrangeable(const ObjectID &id, std::function<void(Arrangeable &)>) override {}
+    ObjectID add_arrangeable(const ObjectID &prototype_id) override { return {}; }
+};
+
+template<class Subclass>
+void SceneBuilderBase<Subclass>::build_scene(Scene &sc) &&
+{
+    if (!m_arrangeable_model)
+        m_arrangeable_model = std::make_unique<EmptyArrangeableModel>();
+
+    if (!m_settings)
+        m_settings = std::make_unique<arr2::ArrangeSettings>();
+
+    coord_t inset = std::max(scaled(m_settings->get_distance_from_bed()),
+                             m_skirt_offs + m_brims_offs);
+
+    coord_t md = scaled(m_settings->get_distance_from_objects());
+    md = md / 2 - inset;
+
+    visit_bed([md](auto &rawbed) { rawbed = offset(rawbed, md); }, m_bed);
+
+    sc.m_settings = std::move(m_settings);
+    sc.m_amodel = std::move(m_arrangeable_model);
+    sc.m_bed = std::move(m_bed);
+}
+
+// Arrange tasks produce an object implementing this interface. The arrange
+// result can be applied to an ArrangeableModel which may or may not succeed.
+// The ArrangeableModel could be in a different state (it's objects may have
+// changed or removed) than it was at the time of arranging.
+class ArrangeResult
+{
+public:
+    virtual ~ArrangeResult() = default;
+
+    virtual bool apply_on(ArrangeableModel &mdlwt) = 0;
+};
+
+enum class Tasks { Arrange, FillBed };
+
+class ArrangeTaskCtl
+{
+public:
+    virtual ~ArrangeTaskCtl() = default;
+
+    virtual void update_status(int st) = 0;
+
+    virtual bool was_canceled() const = 0;
+};
+
+class DummyCtl : public ArrangeTaskCtl
+{
+public:
+    void update_status(int) override {}
+    bool was_canceled() const override { return false; }
+};
+
+class ArrangeTaskBase
+{
+public:
+    using Ctl = ArrangeTaskCtl;
+
+    virtual ~ArrangeTaskBase() = default;
+
+    [[nodiscard]] virtual std::unique_ptr<ArrangeResult> process(Ctl &ctl) = 0;
+
+    [[nodiscard]] virtual int item_count_to_process() const = 0;
+
+    [[nodiscard]] static std::unique_ptr<ArrangeTaskBase> create(
+        Tasks task_type, const Scene &sc);
+
+    [[nodiscard]] std::unique_ptr<ArrangeResult> process(Ctl &&ctl)
+    {
+        return process(ctl);
+    }
+
+    [[nodiscard]] std::unique_ptr<ArrangeResult> process()
+    {
+        return process(DummyCtl{});
+    }
+};
+
+bool arrange(Scene &scene, ArrangeTaskCtl &ctl);
+inline bool arrange(Scene &scene, ArrangeTaskCtl &&ctl = DummyCtl{})
+{
+    return arrange(scene, ctl);
+}
+
+inline bool arrange(Scene &&scene, ArrangeTaskCtl &ctl)
+{
+    return arrange(scene, ctl);
+}
+
+inline bool arrange(Scene &&scene, ArrangeTaskCtl &&ctl = DummyCtl{})
+{
+    return arrange(scene, ctl);
+}
+
+template<class Builder, class Ctl = DummyCtl>
+bool arrange(SceneBuilderBase<Builder> &&builder, Ctl &&ctl = {})
+{
+    return arrange(Scene{std::move(builder)}, ctl);
+}
+
+} // namespace arr2
+} // namespace Slic3r
+
+#endif // ARR2_SCENE_HPP

src/libslic3r/Arrange/SceneBuilder.cpp

@@ -0,0 +1,927 @@
+#ifndef SCENEBUILDER_CPP
+#define SCENEBUILDER_CPP
+
+#include "SceneBuilder.hpp"
+
+#include "libslic3r/Model.hpp"
+#include "libslic3r/Print.hpp"
+#include "libslic3r/SLAPrint.hpp"
+
+#include "Core/ArrangeItemTraits.hpp"
+#include "Geometry/ConvexHull.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+coord_t get_skirt_inset(const Print &fffprint)
+{
+    float skirt_inset = 0.f;
+
+    if (fffprint.has_skirt()) {
+        float skirtflow = fffprint.objects().empty()
+                              ? 0
+                              : fffprint.skirt_flow().width();
+        skirt_inset = fffprint.config().skirts.value * skirtflow
+                      + fffprint.config().skirt_distance.value;
+    }
+
+    return scaled(skirt_inset);
+}
+
+coord_t brim_offset(const PrintObject &po)
+{
+    const BrimType brim_type       = po.config().brim_type.value;
+    const float    brim_separation = po.config().brim_separation.getFloat();
+    const float    brim_width      = po.config().brim_width.getFloat();
+    const bool     has_outer_brim  = brim_type == BrimType::btOuterOnly ||
+                                brim_type == BrimType::btOuterAndInner;
+
+    // How wide is the brim? (in scaled units)
+    return has_outer_brim ? scaled(brim_width + brim_separation) : 0;
+}
+
+size_t model_instance_count (const Model &m)
+{
+    return std::accumulate(m.objects.begin(),
+                           m.objects.end(),
+                           size_t(0),
+                           [](size_t s, const Slic3r::ModelObject *mo) {
+                               return s + mo->instances.size();
+                           });
+}
+
+void transform_instance(ModelInstance     &mi,
+                        const Vec2d       &transl_unscaled,
+                        double             rot,
+                        const Transform3d &physical_tr)
+{
+    auto trafo = mi.get_transformation().get_matrix();
+    auto tr = Transform3d::Identity();
+    tr.translate(to_3d(transl_unscaled, 0.));
+    trafo = physical_tr.inverse() * tr * Eigen::AngleAxisd(rot, Vec3d::UnitZ()) * physical_tr * trafo;
+
+    mi.set_transformation(Geometry::Transformation{trafo});
+
+    mi.invalidate_object_bounding_box();
+}
+
+BoundingBoxf3 instance_bounding_box(const ModelInstance &mi,
+                                    const Transform3d &tr,
+                                    bool dont_translate)
+{
+    BoundingBoxf3 bb;
+    const Transform3d inst_matrix
+        = dont_translate ? mi.get_transformation().get_matrix_no_offset()
+                         : mi.get_transformation().get_matrix();
+
+    for (ModelVolume *v : mi.get_object()->volumes) {
+        if (v->is_model_part()) {
+            bb.merge(v->mesh().transformed_bounding_box(tr * inst_matrix
+                                                        * v->get_matrix()));
+        }
+    }
+
+    return bb;
+}
+
+BoundingBoxf3 instance_bounding_box(const ModelInstance &mi, bool dont_translate)
+{
+    return instance_bounding_box(mi, Transform3d::Identity(), dont_translate);
+}
+
+bool check_coord_bounds(const BoundingBoxf &bb)
+{
+    return std::abs(bb.min.x()) < UnscaledCoordLimit &&
+           std::abs(bb.min.y()) < UnscaledCoordLimit &&
+           std::abs(bb.max.x()) < UnscaledCoordLimit &&
+           std::abs(bb.max.y()) < UnscaledCoordLimit;
+}
+
+ExPolygons extract_full_outline(const ModelInstance &inst, const Transform3d &tr)
+{
+    ExPolygons outline;
+
+    if (check_coord_bounds(to_2d(instance_bounding_box(inst, tr)))) {
+        for (const ModelVolume *v : inst.get_object()->volumes) {
+            Polygons vol_outline;
+
+            vol_outline = project_mesh(v->mesh().its,
+                                       tr * inst.get_matrix() * v->get_matrix(),
+                                       [] {});
+            switch (v->type()) {
+            case ModelVolumeType::MODEL_PART:
+                outline = union_ex(outline, vol_outline);
+                break;
+            case ModelVolumeType::NEGATIVE_VOLUME:
+                outline = diff_ex(outline, vol_outline);
+                break;
+            default:;
+            }
+        }
+    }
+
+    return outline;
+}
+
+Polygon extract_convex_outline(const ModelInstance &inst, const Transform3d &tr)
+{
+    auto bb = to_2d(instance_bounding_box(inst, tr));
+    Polygon ret;
+
+    if (check_coord_bounds(bb)) {
+        ret = inst.get_object()->convex_hull_2d(tr * inst.get_matrix());
+    }
+
+    return ret;
+}
+
+inline static bool is_infinite_bed(const ExtendedBed &ebed) noexcept
+{
+    bool ret = false;
+    visit_bed(
+        [&ret](auto &rawbed) {
+            ret = std::is_convertible_v<decltype(rawbed), InfiniteBed>;
+        },
+        ebed);
+
+    return ret;
+}
+
+void SceneBuilder::set_brim_and_skirt()
+{
+    if (!m_fff_print)
+        return;
+
+    m_brims_offs = 0;
+
+    for (const PrintObject *po : m_fff_print->objects()) {
+        if (po) {
+            m_brims_offs = std::max(m_brims_offs, brim_offset(*po));
+        }
+    }
+
+    m_skirt_offs = get_skirt_inset(*m_fff_print);
+}
+
+void SceneBuilder::build_scene(Scene &sc) &&
+{
+    if (m_sla_print && !m_fff_print) {
+        m_arrangeable_model = std::make_unique<ArrangeableSLAPrint>(m_sla_print.get(), *this);
+    } else {
+        m_arrangeable_model = std::make_unique<ArrangeableSlicerModel>(*this);
+    }
+
+    if (m_fff_print && !m_sla_print) {
+        if (is_infinite_bed(m_bed)) {
+            set_bed(*m_fff_print);
+        } else {
+            set_brim_and_skirt();
+        }
+    }
+
+    std::move(*this).SceneBuilderBase<SceneBuilder>::build_scene(sc);
+}
+
+void SceneBuilder::build_arrangeable_slicer_model(ArrangeableSlicerModel &amodel)
+{
+    if (!m_model)
+        m_model = std::make_unique<Model>();
+
+    if (!m_selection)
+        m_selection = std::make_unique<FixedSelection>(*m_model);
+
+    if (!m_vbed_handler) {
+        m_vbed_handler = VirtualBedHandler::create(m_bed);
+    }
+
+    if (!m_wipetower_handler) {
+        m_wipetower_handler = std::make_unique<MissingWipeTowerHandler>();
+    }
+
+    if (m_fff_print && !m_xl_printer)
+        m_xl_printer = is_XL_printer(m_fff_print->config());
+
+    bool has_wipe_tower = false;
+    m_wipetower_handler->visit(
+        [&has_wipe_tower](const Arrangeable &arrbl) { has_wipe_tower = true; });
+
+    if (m_xl_printer && !has_wipe_tower) {
+        m_bed = XLBed{bounding_box(m_bed)};
+    }
+
+    amodel.m_vbed_handler = std::move(m_vbed_handler);
+    amodel.m_model = std::move(m_model);
+    amodel.m_selmask = std::move(m_selection);
+    amodel.m_wth = std::move(m_wipetower_handler);
+
+    amodel.m_wth->set_selection_predicate(
+        [&amodel] { return amodel.m_selmask->is_wipe_tower(); });
+}
+
+int XStriderVBedHandler::get_bed_index(const VBedPlaceable &obj) const
+{
+    int bedidx = 0;
+    auto stride_s = stride_scaled();
+    if (stride_s > 0) {
+        double bedx = unscaled(m_start);
+        auto instance_bb = obj.bounding_box();
+        auto reference_pos_x = (instance_bb.min.x() - bedx);
+        auto stride = unscaled(stride_s);
+
+        auto bedidx_d = std::floor(reference_pos_x / stride);
+
+        if (bedidx_d < std::numeric_limits<int>::min())
+            bedidx = std::numeric_limits<int>::min();
+        else if (bedidx_d > std::numeric_limits<int>::max())
+            bedidx = std::numeric_limits<int>::max();
+        else
+            bedidx = static_cast<int>(bedidx_d);
+    }
+
+    return bedidx;
+}
+
+bool XStriderVBedHandler::assign_bed(VBedPlaceable &obj, int bed_index)
+{
+    bool ret = false;
+    auto stride_s = stride_scaled();
+    if (bed_index == 0 || (bed_index > 0 && stride_s > 0)) {
+        auto current_bed_index = get_bed_index(obj);
+        auto stride = unscaled(stride_s);
+        auto transl = Vec2d{(bed_index - current_bed_index) * stride, 0.};
+        obj.displace(transl, 0.);
+
+        ret = true;
+    }
+
+    return ret;
+}
+
+Transform3d XStriderVBedHandler::get_physical_bed_trafo(int bed_index) const
+{
+    auto stride_s = stride_scaled();
+    auto tr = Transform3d::Identity();
+    tr.translate(Vec3d{-bed_index * unscaled(stride_s), 0., 0.});
+
+    return tr;
+}
+
+int YStriderVBedHandler::get_bed_index(const VBedPlaceable &obj) const
+{
+    int bedidx = 0;
+    auto stride_s = stride_scaled();
+    if (stride_s > 0) {
+        double ystart = unscaled(m_start);
+        auto instance_bb = obj.bounding_box();
+        auto reference_pos_y = (instance_bb.min.y() - ystart);
+        auto stride = unscaled(stride_s);
+
+        auto bedidx_d = std::floor(reference_pos_y / stride);
+
+        if (bedidx_d < std::numeric_limits<int>::min())
+            bedidx = std::numeric_limits<int>::min();
+        else if (bedidx_d > std::numeric_limits<int>::max())
+            bedidx = std::numeric_limits<int>::max();
+        else
+            bedidx = static_cast<int>(bedidx_d);
+    }
+
+    return bedidx;
+}
+
+bool YStriderVBedHandler::assign_bed(VBedPlaceable &obj, int bed_index)
+{
+    bool ret = false;
+    auto stride_s = stride_scaled();
+    if (bed_index == 0 || (bed_index > 0 && stride_s > 0)) {
+        auto current_bed_index = get_bed_index(obj);
+        auto stride = unscaled(stride_s);
+        auto transl = Vec2d{0., (bed_index - current_bed_index) * stride};
+        obj.displace(transl, 0.);
+
+        ret = true;
+    }
+
+    return ret;
+}
+
+Transform3d YStriderVBedHandler::get_physical_bed_trafo(int bed_index) const
+{
+    auto stride_s = stride_scaled();
+    auto tr = Transform3d::Identity();
+    tr.translate(Vec3d{0., -bed_index * unscaled(stride_s), 0.});
+
+    return tr;
+}
+
+const int GridStriderVBedHandler::Cols =
+    2 * static_cast<int>(std::sqrt(std::numeric_limits<int>::max()) / 2);
+
+const int GridStriderVBedHandler::HalfCols = Cols / 2;
+const int GridStriderVBedHandler::Offset = HalfCols + Cols * HalfCols;
+
+Vec2i GridStriderVBedHandler::raw2grid(int bed_idx) const
+{
+    bed_idx += Offset;
+
+    Vec2i ret{bed_idx % Cols - HalfCols, bed_idx / Cols - HalfCols};
+
+    return ret;
+}
+
+int GridStriderVBedHandler::grid2raw(const Vec2i &crd) const
+{
+    // Overlapping virtual beds will happen if the crd values exceed limits
+    assert((crd.x() < HalfCols - 1 && crd.x() >= -HalfCols) &&
+           (crd.y() < HalfCols - 1 && crd.y() >= -HalfCols));
+
+    return (crd.x() + HalfCols) + Cols * (crd.y() + HalfCols) - Offset;
+}
+
+int GridStriderVBedHandler::get_bed_index(const VBedPlaceable &obj) const
+{
+    Vec2i crd = {m_xstrider.get_bed_index(obj), m_ystrider.get_bed_index(obj)};
+
+    return grid2raw(crd);
+}
+
+bool GridStriderVBedHandler::assign_bed(VBedPlaceable &inst, int bed_idx)
+{
+    Vec2i crd = raw2grid(bed_idx);
+
+    bool retx = m_xstrider.assign_bed(inst, crd.x());
+    bool rety = m_ystrider.assign_bed(inst, crd.y());
+
+    return retx && rety;
+}
+
+Transform3d GridStriderVBedHandler::get_physical_bed_trafo(int bed_idx) const
+{
+    Vec2i crd = raw2grid(bed_idx);
+
+    Transform3d ret = m_xstrider.get_physical_bed_trafo(crd.x()) *
+                      m_ystrider.get_physical_bed_trafo(crd.y());
+
+    return ret;
+}
+
+FixedSelection::FixedSelection(const Model &m) : m_wp{true}
+{
+    m_seldata.resize(m.objects.size());
+    for (size_t i = 0; i < m.objects.size(); ++i) {
+        m_seldata[i].resize(m.objects[i]->instances.size(), true);
+    }
+}
+
+FixedSelection::FixedSelection(const SelectionMask &other)
+{
+    auto obj_sel = other.selected_objects();
+    m_seldata.reserve(obj_sel.size());
+    for (int oidx = 0; oidx < static_cast<int>(obj_sel.size()); ++oidx)
+        m_seldata.emplace_back(other.selected_instances(oidx));
+}
+
+std::vector<bool> FixedSelection::selected_objects() const
+{
+    auto ret = Slic3r::reserve_vector<bool>(m_seldata.size());
+    std::transform(m_seldata.begin(),
+                   m_seldata.end(),
+                   std::back_inserter(ret),
+                   [](auto &a) {
+                       return std::any_of(a.begin(), a.end(), [](bool b) {
+                           return b;
+                       });
+                   });
+    return ret;
+}
+
+static std::vector<size_t> find_true_indices(const std::vector<bool> &v)
+{
+    auto ret = reserve_vector<size_t>(v.size());
+
+    for (size_t i = 0; i < v.size(); ++i)
+        if (v[i])
+            ret.emplace_back(i);
+
+    return ret;
+}
+
+std::vector<size_t> selected_object_indices(const SelectionMask &sm)
+{
+    auto sel = sm.selected_objects();
+    return find_true_indices(sel);
+}
+
+std::vector<size_t> selected_instance_indices(int obj_idx, const SelectionMask &sm)
+{
+    auto sel = sm.selected_instances(obj_idx);
+    return find_true_indices(sel);
+}
+
+SceneBuilder::SceneBuilder() = default;
+SceneBuilder::~SceneBuilder() = default;
+SceneBuilder::SceneBuilder(SceneBuilder &&) = default;
+SceneBuilder& SceneBuilder::operator=(SceneBuilder&&) = default;
+
+SceneBuilder &&SceneBuilder::set_model(AnyPtr<Model> mdl)
+{
+    m_model = std::move(mdl);
+    return std::move(*this);
+}
+
+SceneBuilder &&SceneBuilder::set_model(Model &mdl)
+{
+    m_model = &mdl;
+    return std::move(*this);
+}
+
+SceneBuilder &&SceneBuilder::set_fff_print(AnyPtr<const Print> mdl_print)
+{
+    m_fff_print = std::move(mdl_print);
+    return std::move(*this);
+}
+
+SceneBuilder &&SceneBuilder::set_sla_print(AnyPtr<const SLAPrint> mdl_print)
+{
+    m_sla_print = std::move(mdl_print);
+
+    return std::move(*this);
+}
+
+SceneBuilder &&SceneBuilder::set_bed(const DynamicPrintConfig &cfg)
+{
+    Points bedpts = get_bed_shape(cfg);
+
+    if (is_XL_printer(cfg)) {
+        m_xl_printer = true;
+    }
+
+    m_bed = arr2::to_arrange_bed(bedpts);
+
+    return std::move(*this);
+}
+
+SceneBuilder &&SceneBuilder::set_bed(const Print &print)
+{
+    Points bedpts = get_bed_shape(print.config());
+
+    if (is_XL_printer(print.config())) {
+        m_bed = XLBed{get_extents(bedpts)};
+    } else {
+        m_bed = arr2::to_arrange_bed(bedpts);
+    }
+
+    set_brim_and_skirt();
+
+    return std::move(*this);
+}
+
+SceneBuilder &&SceneBuilder::set_sla_print(const SLAPrint *slaprint)
+{
+    m_sla_print = slaprint;
+    return std::move(*this);
+}
+
+int ArrangeableWipeTowerBase::get_bed_index() const { return PhysicalBedId; }
+
+bool ArrangeableWipeTowerBase::assign_bed(int bed_idx)
+{
+    return bed_idx == PhysicalBedId;
+}
+
+bool PhysicalOnlyVBedHandler::assign_bed(VBedPlaceable &inst, int bed_idx)
+{
+    return bed_idx == PhysicalBedId;
+}
+
+ArrangeableSlicerModel::ArrangeableSlicerModel(SceneBuilder &builder)
+{
+    builder.build_arrangeable_slicer_model(*this);
+}
+
+ArrangeableSlicerModel::~ArrangeableSlicerModel() = default;
+
+void ArrangeableSlicerModel::for_each_arrangeable(
+    std::function<void(Arrangeable &)> fn)
+{
+    for_each_arrangeable_(*this, fn);
+
+    m_wth->visit(fn);
+}
+
+void ArrangeableSlicerModel::for_each_arrangeable(
+    std::function<void(const Arrangeable &)> fn) const
+{
+    for_each_arrangeable_(*this, fn);
+
+    m_wth->visit(fn);
+}
+
+ObjectID ArrangeableSlicerModel::add_arrangeable(const ObjectID &prototype_id)
+{
+    ObjectID ret;
+
+    auto [inst, pos] = find_instance_by_id(*m_model, prototype_id);
+    if (inst) {
+        auto new_inst = inst->get_object()->add_instance(*inst);
+        if (new_inst) {
+            ret = new_inst->id();
+        }
+    }
+
+    return ret;
+}
+
+template<class Self, class Fn>
+void ArrangeableSlicerModel::for_each_arrangeable_(Self &&self, Fn &&fn)
+{
+    InstPos pos;
+    for (auto *obj : self.m_model->objects) {
+        for (auto *inst : obj->instances) {
+            ArrangeableModelInstance ainst{inst, self.m_vbed_handler.get(), self.m_selmask.get(), pos};
+            fn(ainst);
+            ++pos.inst_idx;
+        }
+        pos.inst_idx = 0;
+        ++pos.obj_idx;
+    }
+}
+
+template<class Self, class Fn>
+void ArrangeableSlicerModel::visit_arrangeable_(Self &&self, const ObjectID &id, Fn &&fn)
+{
+    if (id == self.m_model->wipe_tower.id()) {
+        self.m_wth->visit(fn);
+
+        return;
+    }
+
+    auto [inst, pos] = find_instance_by_id(*self.m_model, id);
+
+    if (inst) {
+        ArrangeableModelInstance ainst{inst, self.m_vbed_handler.get(), self.m_selmask.get(), pos};
+        fn(ainst);
+    }
+}
+
+void ArrangeableSlicerModel::visit_arrangeable(
+    const ObjectID &id, std::function<void(const Arrangeable &)> fn) const
+{
+    visit_arrangeable_(*this, id, fn);
+}
+
+void ArrangeableSlicerModel::visit_arrangeable(
+    const ObjectID &id, std::function<void(Arrangeable &)> fn)
+{
+    visit_arrangeable_(*this, id, fn);
+}
+
+template<class Self, class Fn>
+void ArrangeableSLAPrint::for_each_arrangeable_(Self &&self, Fn &&fn)
+{
+    InstPos pos;
+    for (auto *obj : self.m_model->objects) {
+        for (auto *inst : obj->instances) {
+            ArrangeableModelInstance ainst{inst, self.m_vbed_handler.get(),
+                                           self.m_selmask.get(), pos};
+
+            auto obj_id = inst->get_object()->id();
+            const SLAPrintObject *po =
+                self.m_slaprint->get_print_object_by_model_object_id(obj_id);
+
+            if (po) {
+                auto &vbh = self.m_vbed_handler;
+                auto phtr = vbh->get_physical_bed_trafo(vbh->get_bed_index(VBedPlaceableMI{*inst}));
+                ArrangeableSLAPrintObject ainst_po{po, &ainst, phtr * inst->get_matrix()};
+                fn(ainst_po);
+            } else {
+                fn(ainst);
+            }
+
+            ++pos.inst_idx;
+        }
+        pos.inst_idx = 0;
+        ++pos.obj_idx;
+    }
+}
+
+void ArrangeableSLAPrint::for_each_arrangeable(
+    std::function<void(Arrangeable &)> fn)
+{
+    for_each_arrangeable_(*this, fn);
+
+    m_wth->visit(fn);
+}
+
+void ArrangeableSLAPrint::for_each_arrangeable(
+    std::function<void(const Arrangeable &)> fn) const
+{
+    for_each_arrangeable_(*this, fn);
+
+    m_wth->visit(fn);
+}
+
+template<class Self, class Fn>
+void ArrangeableSLAPrint::visit_arrangeable_(Self &&self, const ObjectID &id, Fn &&fn)
+{
+    auto [inst, pos] = find_instance_by_id(*self.m_model, id);
+
+    if (inst) {
+        ArrangeableModelInstance ainst{inst, self.m_vbed_handler.get(),
+                                       self.m_selmask.get(), pos};
+
+        auto obj_id = inst->get_object()->id();
+        const SLAPrintObject *po =
+            self.m_slaprint->get_print_object_by_model_object_id(obj_id);
+
+        if (po) {
+            auto &vbh = self.m_vbed_handler;
+            auto phtr = vbh->get_physical_bed_trafo(vbh->get_bed_index(VBedPlaceableMI{*inst}));
+            ArrangeableSLAPrintObject ainst_po{po, &ainst, phtr * inst->get_matrix()};
+            fn(ainst_po);
+        } else {
+            fn(ainst);
+        }
+    }
+}
+
+void ArrangeableSLAPrint::visit_arrangeable(
+    const ObjectID &id, std::function<void(const Arrangeable &)> fn) const
+{
+    visit_arrangeable_(*this, id, fn);
+}
+
+void ArrangeableSLAPrint::visit_arrangeable(
+    const ObjectID &id, std::function<void(Arrangeable &)> fn)
+{
+    visit_arrangeable_(*this, id, fn);
+}
+
+template<class InstPtr, class VBedHPtr>
+ExPolygons ArrangeableModelInstance<InstPtr, VBedHPtr>::full_outline() const
+{
+    int bedidx = m_vbedh->get_bed_index(*this);
+    auto tr = m_vbedh->get_physical_bed_trafo(bedidx);
+
+    return extract_full_outline(*m_mi, tr);
+}
+
+template<class InstPtr, class VBedHPtr>
+Polygon ArrangeableModelInstance<InstPtr, VBedHPtr>::convex_outline() const
+{
+    int bedidx = m_vbedh->get_bed_index(*this);
+    auto tr = m_vbedh->get_physical_bed_trafo(bedidx);
+
+    return extract_convex_outline(*m_mi, tr);
+}
+
+template<class InstPtr, class VBedHPtr>
+bool ArrangeableModelInstance<InstPtr, VBedHPtr>::is_selected() const
+{
+    bool ret = false;
+
+    if (m_selmask) {
+        auto sel = m_selmask->selected_instances(m_pos_within_model.obj_idx);
+        if (m_pos_within_model.inst_idx < sel.size() &&
+            sel[m_pos_within_model.inst_idx])
+            ret = true;
+    }
+
+    return ret;
+}
+
+template<class InstPtr, class VBedHPtr>
+void ArrangeableModelInstance<InstPtr, VBedHPtr>::transform(const Vec2d &transl, double rot)
+{
+    if constexpr (!std::is_const_v<InstPtr> && !std::is_const_v<VBedHPtr>) {
+        int bedidx = m_vbedh->get_bed_index(*this);
+        auto physical_trafo = m_vbedh->get_physical_bed_trafo(bedidx);
+
+        transform_instance(*m_mi, transl, rot, physical_trafo);
+    }
+}
+
+template<class InstPtr, class VBedHPtr>
+bool ArrangeableModelInstance<InstPtr, VBedHPtr>::assign_bed(int bed_idx)
+{
+    bool ret = false;
+
+    if constexpr (!std::is_const_v<InstPtr> && !std::is_const_v<VBedHPtr>)
+        ret = m_vbedh->assign_bed(*this, bed_idx);
+
+    return ret;
+}
+
+template class ArrangeableModelInstance<ModelInstance, VirtualBedHandler>;
+template class ArrangeableModelInstance<const ModelInstance, const VirtualBedHandler>;
+
+ExPolygons ArrangeableSLAPrintObject::full_outline() const
+{
+    ExPolygons ret;
+
+    auto laststep = m_po->last_completed_step();
+    if (laststep < slaposCount && laststep > slaposSupportTree) {
+        Polygons polys;
+        auto omesh = m_po->get_mesh_to_print();
+        auto &smesh = m_po->support_mesh();
+
+        Transform3d trafo_instance = m_inst_trafo * m_po->trafo().inverse();
+
+        if (omesh) {
+            Polygons ptmp = project_mesh(*omesh, trafo_instance, [] {});
+            std::move(ptmp.begin(), ptmp.end(), std::back_inserter(polys));
+        }
+
+        Polygons ptmp = project_mesh(smesh.its, trafo_instance, [] {});
+        std::move(ptmp.begin(), ptmp.end(), std::back_inserter(polys));
+        ret = union_ex(polys);
+    } else {
+        ret = m_arrbl->full_outline();
+    }
+
+    return ret;
+}
+
+ExPolygons ArrangeableSLAPrintObject::full_envelope() const
+{
+    ExPolygons ret = full_outline();
+
+    auto laststep = m_po->last_completed_step();
+    if (laststep < slaposCount && laststep > slaposSupportTree) {
+        auto &pmesh = m_po->pad_mesh();
+        if (!pmesh.empty()) {
+
+            Transform3d trafo_instance = m_inst_trafo * m_po->trafo().inverse();
+
+            Polygons ptmp = project_mesh(pmesh.its, trafo_instance, [] {});
+            ret = union_ex(ret, ptmp);
+        }
+    }
+
+    return ret;
+}
+
+Polygon ArrangeableSLAPrintObject::convex_outline() const
+{
+    Polygons polys;
+
+    polys.emplace_back(m_arrbl->convex_outline());
+
+    auto laststep = m_po->last_completed_step();
+    if (laststep < slaposCount && laststep > slaposSupportTree) {
+        auto omesh = m_po->get_mesh_to_print();
+        auto &smesh = m_po->support_mesh();
+
+        Transform3f trafo_instance = m_inst_trafo.cast<float>();
+        trafo_instance = trafo_instance * m_po->trafo().cast<float>().inverse();
+
+        Polygons polys;
+        polys.reserve(3);
+        auto zlvl = -m_po->get_elevation();
+
+        if (omesh) {
+            polys.emplace_back(
+                its_convex_hull_2d_above(*omesh, trafo_instance, zlvl));
+        }
+
+        polys.emplace_back(
+            its_convex_hull_2d_above(smesh.its, trafo_instance, zlvl));
+    }
+
+    return Geometry::convex_hull(polys);
+}
+
+Polygon ArrangeableSLAPrintObject::convex_envelope() const
+{
+    Polygons polys;
+
+    polys.emplace_back(convex_outline());
+
+    auto laststep = m_po->last_completed_step();
+    if (laststep < slaposCount && laststep > slaposSupportTree) {
+        auto &pmesh = m_po->pad_mesh();
+        if (!pmesh.empty()) {
+
+            Transform3f trafo_instance = m_inst_trafo.cast<float>();
+            trafo_instance = trafo_instance * m_po->trafo().cast<float>().inverse();
+            auto zlvl = -m_po->get_elevation();
+
+            polys.emplace_back(
+                its_convex_hull_2d_above(pmesh.its, trafo_instance, zlvl));
+        }
+    }
+
+    return Geometry::convex_hull(polys);
+}
+
+DuplicableModel::DuplicableModel(AnyPtr<Model> mdl, AnyPtr<VirtualBedHandler> vbh, const BoundingBox &bedbb)
+    : m_model{std::move(mdl)}, m_vbh{std::move(vbh)}, m_duplicates(1), m_bedbb{bedbb}
+{
+}
+
+DuplicableModel::~DuplicableModel() = default;
+
+ObjectID DuplicableModel::add_arrangeable(const ObjectID &prototype_id)
+{
+    ObjectID ret;
+    if (prototype_id.valid()) {
+        size_t idx = prototype_id.id - 1;
+        if (idx < m_duplicates.size()) {
+            ModelDuplicate md = m_duplicates[idx];
+            md.id = m_duplicates.size();
+            ret = md.id.id + 1;
+            m_duplicates.emplace_back(std::move(md));
+        }
+    }
+
+    return ret;
+}
+
+void DuplicableModel::apply_duplicates()
+{
+    for (ModelObject *o : m_model->objects) {
+        // make a copy of the pointers in order to avoid recursion
+        // when appending their copies
+        ModelInstancePtrs instances = o->instances;
+        o->instances.clear();
+        for (const ModelInstance *i : instances) {
+            for (const ModelDuplicate &md : m_duplicates) {
+                ModelInstance *instance = o->add_instance(*i);
+                arr2::transform_instance(*instance, md.tr, md.rot);
+            }
+        }
+        for (auto *i : instances)
+            delete i;
+
+        instances.clear();
+
+        o->invalidate_bounding_box();
+    }
+}
+
+template<class Mdl, class Dup, class VBH>
+ObjectID ArrangeableFullModel<Mdl, Dup, VBH>::geometry_id() const { return m_mdl->id(); }
+
+template<class Mdl, class Dup, class VBH>
+ExPolygons ArrangeableFullModel<Mdl, Dup, VBH>::full_outline() const
+{
+    auto ret = reserve_vector<ExPolygon>(arr2::model_instance_count(*m_mdl));
+
+    auto transl = Transform3d::Identity();
+    transl.translate(to_3d(m_dup->tr, 0.));
+    Transform3d trafo = transl* Eigen::AngleAxisd(m_dup->rot, Vec3d::UnitZ());
+
+    for (auto *mo : m_mdl->objects) {
+        for (auto *mi : mo->instances) {
+            auto expolys = arr2::extract_full_outline(*mi, trafo);
+            std::move(expolys.begin(), expolys.end(), std::back_inserter(ret));
+        }
+    }
+
+    return ret;
+}
+
+template<class Mdl, class Dup, class VBH>
+Polygon ArrangeableFullModel<Mdl, Dup, VBH>::convex_outline() const
+{
+    auto ret = reserve_polygons(arr2::model_instance_count(*m_mdl));
+
+    auto transl = Transform3d::Identity();
+    transl.translate(to_3d(m_dup->tr, 0.));
+    Transform3d trafo = transl* Eigen::AngleAxisd(m_dup->rot, Vec3d::UnitZ());
+
+    for (auto *mo : m_mdl->objects) {
+        for (auto *mi : mo->instances) {
+            ret.emplace_back(arr2::extract_convex_outline(*mi, trafo));
+        }
+    }
+
+    return Geometry::convex_hull(ret);
+}
+
+template class ArrangeableFullModel<Model, ModelDuplicate, VirtualBedHandler>;
+template class ArrangeableFullModel<const Model, const ModelDuplicate, const VirtualBedHandler>;
+
+std::unique_ptr<VirtualBedHandler> VirtualBedHandler::create(const ExtendedBed &bed)
+{
+    std::unique_ptr<VirtualBedHandler> ret;
+    if (is_infinite_bed(bed)) {
+        ret = std::make_unique<PhysicalOnlyVBedHandler>();
+    } else {
+        // The gap between logical beds expressed in ratio of
+        // the current bed width.
+        constexpr double LogicalBedGap = 1. / 10.;
+
+        BoundingBox bedbb;
+        visit_bed([&bedbb](auto &rawbed) { bedbb = bounding_box(rawbed); }, bed);
+
+        auto bedwidth = bedbb.size().x();
+        coord_t xgap = LogicalBedGap * bedwidth;
+        ret = std::make_unique<GridStriderVBedHandler>(bedbb, xgap);
+    }
+
+    return ret;
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // SCENEBUILDER_CPP

src/libslic3r/Arrange/SceneBuilder.hpp

@@ -0,0 +1,677 @@
+#ifndef SCENEBUILDER_HPP
+#define SCENEBUILDER_HPP
+
+#include "Scene.hpp"
+
+#include "Core/ArrangeItemTraits.hpp"
+
+namespace Slic3r {
+
+class Model;
+class ModelInstance;
+class ModelWipeTower;
+class Print;
+class SLAPrint;
+class SLAPrintObject;
+class PrintObject;
+class DynamicPrintConfig;
+
+namespace arr2 {
+
+using SelectionPredicate = std::function<bool()>;
+
+class WipeTowerHandler
+{
+public:
+    virtual ~WipeTowerHandler() = default;
+
+    virtual void visit(std::function<void(Arrangeable &)>) = 0;
+    virtual void visit(std::function<void(const Arrangeable &)>) const = 0;
+    virtual void set_selection_predicate(SelectionPredicate pred) = 0;
+};
+
+class VBedPlaceable {
+public:
+    virtual ~VBedPlaceable() = default;
+
+    virtual BoundingBoxf bounding_box() const = 0;
+    virtual void displace(const Vec2d &transl, double rot) = 0;
+};
+
+// An interface to handle virtual beds for ModelInstances. A ModelInstance
+// may be assigned to a logical bed identified by an integer index value (zero
+// is the actual physical bed). The ModelInstance may still be outside of it's
+// bed, regardless of being assigned to it. The handler object should provide
+// means to read the assigned bed index of a ModelInstance, to assign a
+// different bed index and to provide a trafo that maps it to the physical bed
+// given a logical bed index. The reason is that the arrangement expects items
+// to be in the coordinate system of the physical bed.
+class VirtualBedHandler
+{
+public:
+    virtual ~VirtualBedHandler() = default;
+
+    // Returns the bed index on which the given ModelInstance is sitting.
+    virtual int get_bed_index(const VBedPlaceable &obj) const = 0;
+
+    // The returned trafo can be used to move the outline of the ModelInstance
+    // to the coordinate system of the physical bed, should that differ from
+    // the coordinate space of a logical bed.
+    virtual Transform3d get_physical_bed_trafo(int bed_index) const = 0;
+
+    // Assign the ModelInstance to the given bed index. Note that this
+    // method can return false, indicating that the given bed is not available
+    // to be occupied (e.g. the handler has a limited amount of logical bed)
+    virtual bool assign_bed(VBedPlaceable &obj, int bed_idx) = 0;
+
+    bool assign_bed(VBedPlaceable &&obj, int bed_idx)
+    {
+        return assign_bed(obj, bed_idx);
+    }
+
+    static std::unique_ptr<VirtualBedHandler> create(const ExtendedBed &bed);
+};
+
+class SelectionMask
+{
+public:
+    virtual ~SelectionMask() = default;
+
+    virtual std::vector<bool> selected_objects() const = 0;
+    virtual std::vector<bool> selected_instances(int obj_id) const = 0;
+    virtual bool is_wipe_tower() const = 0;
+};
+
+class FixedSelection : public Slic3r::arr2::SelectionMask
+{
+    std::vector<std::vector<bool>> m_seldata;
+    bool                           m_wp = false;
+
+public:
+    FixedSelection() = default;
+
+    explicit FixedSelection(std::initializer_list<std::vector<bool>> seld,
+                            bool wp = false)
+        : m_seldata{std::move(seld)}, m_wp{wp}
+    {}
+
+    explicit FixedSelection(const Model &m);
+
+    explicit FixedSelection(const SelectionMask &other);
+
+    std::vector<bool> selected_objects() const override;
+
+    std::vector<bool> selected_instances(int obj_id) const override
+    {
+        return obj_id < int(m_seldata.size()) ? m_seldata[obj_id] :
+                                                std::vector<bool>{};
+    }
+
+    bool is_wipe_tower() const override { return m_wp; }
+};
+
+struct ArrangeableWipeTowerBase: public Arrangeable
+{
+    ObjectID oid;
+
+    Polygon poly;
+    SelectionPredicate selection_pred;
+
+    ArrangeableWipeTowerBase(
+        const ObjectID &objid,
+        Polygon shape,
+        SelectionPredicate selection_predicate = [] { return false; })
+        : oid{objid},
+          poly{std::move(shape)},
+          selection_pred{std::move(selection_predicate)}
+    {}
+
+    ObjectID id() const override { return oid; }
+    ObjectID geometry_id() const override { return {}; }
+
+    ExPolygons full_outline() const override
+    {
+        auto cpy = poly;
+        return {ExPolygon{std::move(cpy)}};
+    }
+
+    Polygon convex_outline() const override
+    {
+        return poly;
+    }
+
+    bool is_selected() const override
+    {
+        return selection_pred();
+    }
+
+    int get_bed_index() const override;
+    bool assign_bed(int /*bed_idx*/) override;
+
+    int priority() const override { return 1; }
+
+    void transform(const Vec2d &transl, double rot) override {}
+
+    void imbue_data(AnyWritable &datastore) const override
+    {
+        datastore.write("is_wipe_tower", {});
+    }
+};
+
+class SceneBuilder;
+
+struct InstPos { size_t obj_idx = 0, inst_idx = 0; };
+
+class ArrangeableSlicerModel: public ArrangeableModel
+{
+protected:
+    AnyPtr<Model> m_model;
+    AnyPtr<WipeTowerHandler> m_wth;
+    AnyPtr<VirtualBedHandler> m_vbed_handler;
+    AnyPtr<const SelectionMask> m_selmask;
+
+private:
+    friend class SceneBuilder;
+
+    template<class Self, class Fn>
+    static void for_each_arrangeable_(Self &&self, Fn &&fn);
+
+    template<class Self, class Fn>
+    static void visit_arrangeable_(Self &&self, const ObjectID &id, Fn &&fn);
+
+public:
+    explicit ArrangeableSlicerModel(SceneBuilder &builder);
+    ~ArrangeableSlicerModel();
+
+    void for_each_arrangeable(std::function<void(Arrangeable &)>) override;
+    void for_each_arrangeable(std::function<void(const Arrangeable&)>) const override;
+
+    void visit_arrangeable(const ObjectID &id, std::function<void(const Arrangeable &)>) const override;
+    void visit_arrangeable(const ObjectID &id, std::function<void(Arrangeable &)>) override;
+
+    ObjectID add_arrangeable(const ObjectID &prototype_id) override;
+
+    Model & get_model() { return *m_model; }
+    const Model &get_model() const { return *m_model; }
+};
+
+class SceneBuilder: public SceneBuilderBase<SceneBuilder>
+{
+protected:
+    AnyPtr<Model> m_model;
+    AnyPtr<WipeTowerHandler> m_wipetower_handler;
+    AnyPtr<VirtualBedHandler> m_vbed_handler;
+    AnyPtr<const SelectionMask> m_selection;
+
+    AnyPtr<const SLAPrint> m_sla_print;
+    AnyPtr<const Print>    m_fff_print;
+    bool m_xl_printer = false;
+
+    void set_brim_and_skirt();
+
+public:
+    SceneBuilder();
+    ~SceneBuilder();
+    SceneBuilder(SceneBuilder&&);
+    SceneBuilder& operator=(SceneBuilder&&);
+
+    SceneBuilder && set_model(AnyPtr<Model> mdl);
+
+    SceneBuilder && set_model(Model &mdl);
+
+    SceneBuilder && set_fff_print(AnyPtr<const Print> fffprint);
+    SceneBuilder && set_sla_print(AnyPtr<const SLAPrint> mdl_print);
+
+    using SceneBuilderBase<SceneBuilder>::set_bed;
+
+    SceneBuilder &&set_bed(const DynamicPrintConfig &cfg);
+    SceneBuilder &&set_bed(const Print &print);
+
+    SceneBuilder && set_wipe_tower_handler(WipeTowerHandler &wth)
+    {
+        m_wipetower_handler = &wth;
+        return std::move(*this);
+    }
+
+    SceneBuilder && set_wipe_tower_handler(AnyPtr<WipeTowerHandler> wth)
+    {
+        m_wipetower_handler = std::move(wth);
+        return std::move(*this);
+    }
+
+    SceneBuilder && set_virtual_bed_handler(AnyPtr<VirtualBedHandler> vbedh)
+    {
+        m_vbed_handler = std::move(vbedh);
+        return std::move(*this);
+    }
+
+    SceneBuilder && set_sla_print(const SLAPrint *slaprint);
+
+    SceneBuilder && set_selection(AnyPtr<const SelectionMask> sel)
+    {
+        m_selection = std::move(sel);
+        return std::move(*this);
+    }
+
+    // Can only be called on an rvalue instance (hence the && at the end),
+    // the method will potentially move its content into sc
+    void build_scene(Scene &sc) && override;
+
+    void build_arrangeable_slicer_model(ArrangeableSlicerModel &amodel);
+};
+
+struct MissingWipeTowerHandler : public WipeTowerHandler
+{
+    void visit(std::function<void(Arrangeable &)>) override {}
+    void visit(std::function<void(const Arrangeable &)>) const override {}
+    void set_selection_predicate(std::function<bool()>) override {}
+};
+
+// Only a physical bed, non-zero bed index values are discarded.
+class PhysicalOnlyVBedHandler final : public VirtualBedHandler
+{
+public:
+    using VirtualBedHandler::assign_bed;
+
+    int get_bed_index(const VBedPlaceable &obj) const override { return 0; }
+
+    Transform3d get_physical_bed_trafo(int bed_index) const override
+    {
+        return Transform3d::Identity();
+    }
+
+    bool assign_bed(VBedPlaceable &inst, int bed_idx) override;
+};
+
+// A virtual bed handler implementation, that defines logical beds to be created
+// on the right side of the physical bed along the X axis in a row
+class XStriderVBedHandler final : public VirtualBedHandler
+{
+    coord_t m_stride_scaled;
+    coord_t m_start;
+
+public:
+    explicit XStriderVBedHandler(const BoundingBox &bedbb, coord_t xgap)
+        : m_stride_scaled{bedbb.size().x() + 2 * std::max(0, xgap)},
+          m_start{bedbb.min.x() - std::max(0, xgap)}
+    {
+    }
+
+    coord_t stride_scaled() const { return m_stride_scaled; }
+
+    // Can return negative indices when the instance is to the left of the
+    // physical bed
+    int get_bed_index(const VBedPlaceable &obj) const override;
+
+    // Only positive beds are accepted
+    bool assign_bed(VBedPlaceable &inst, int bed_idx) override;
+
+    using VirtualBedHandler::assign_bed;
+
+    Transform3d get_physical_bed_trafo(int bed_index) const override;
+};
+
+// Same as XStriderVBedHandler only that it lays out vbeds on the Y axis
+class YStriderVBedHandler final : public VirtualBedHandler
+{
+    coord_t m_stride_scaled;
+    coord_t m_start;
+
+public:
+    coord_t stride_scaled() const { return m_stride_scaled; }
+
+    explicit YStriderVBedHandler(const BoundingBox &bedbb, coord_t ygap)
+        : m_stride_scaled{bedbb.size().y() + 2 * std::max(0, ygap)}
+        , m_start{bedbb.min.y() - std::max(0, ygap)}
+    {}
+
+    int get_bed_index(const VBedPlaceable &obj) const override;
+    bool assign_bed(VBedPlaceable &inst, int bed_idx) override;
+
+    Transform3d get_physical_bed_trafo(int bed_index) const override;
+};
+
+class GridStriderVBedHandler: public VirtualBedHandler
+{
+    // This vbed handler defines a grid of virtual beds with a large number
+    // of columns so that it behaves as XStrider for regular cases.
+    // The goal is to handle objects residing at world coordinates
+    // not representable with scaled coordinates. Combining XStrider with
+    // YStrider takes care of the X and Y axis to be mapped into the physical
+    // bed's coordinate region (which is representable in scaled coords)
+    static const int Cols;
+    static const int HalfCols;
+    static const int Offset;
+
+    XStriderVBedHandler m_xstrider;
+    YStriderVBedHandler m_ystrider;
+
+public:
+    GridStriderVBedHandler(const BoundingBox &bedbb,
+                           coord_t            gap)
+        : m_xstrider{bedbb, gap}
+        , m_ystrider{bedbb, gap}
+    {}
+
+    Vec2i raw2grid(int bedidx) const;
+    int grid2raw(const Vec2i &crd) const;
+
+    int get_bed_index(const VBedPlaceable &obj) const override;
+    bool assign_bed(VBedPlaceable &inst, int bed_idx) override;
+
+    Transform3d get_physical_bed_trafo(int bed_index) const override;
+};
+
+std::vector<size_t> selected_object_indices(const SelectionMask &sm);
+std::vector<size_t> selected_instance_indices(int obj_idx, const SelectionMask &sm);
+
+coord_t get_skirt_inset(const Print &fffprint);
+
+coord_t brim_offset(const PrintObject &po);
+
+// unscaled coords are necessary to be able to handle bigger coordinate range
+// than what is available with scaled coords. This is useful when working with
+// virtual beds.
+void transform_instance(ModelInstance     &mi,
+                        const Vec2d       &transl_unscaled,
+                        double             rot,
+                        const Transform3d &physical_tr = Transform3d::Identity());
+
+BoundingBoxf3 instance_bounding_box(const ModelInstance &mi,
+                                    bool dont_translate = false);
+
+BoundingBoxf3 instance_bounding_box(const ModelInstance &mi,
+                                    const Transform3d &tr,
+                                    bool dont_translate = false);
+
+constexpr double UnscaledCoordLimit = 1000.;
+
+ExPolygons extract_full_outline(const ModelInstance &inst,
+                                const Transform3d &tr = Transform3d::Identity());
+
+Polygon extract_convex_outline(const ModelInstance &inst,
+                               const Transform3d &tr = Transform3d::Identity());
+
+size_t model_instance_count (const Model &m);
+
+class VBedPlaceableMI : public VBedPlaceable
+{
+    ModelInstance *m_mi;
+
+public:
+    explicit VBedPlaceableMI(ModelInstance &mi) : m_mi{&mi} {}
+
+    BoundingBoxf bounding_box() const override { return to_2d(instance_bounding_box(*m_mi)); }
+    void         displace(const Vec2d &transl, double rot) override
+    {
+        transform_instance(*m_mi, transl, rot);
+    }
+};
+
+template<class InstPtr, class VBedHPtr>
+class ArrangeableModelInstance : public Arrangeable, VBedPlaceable
+{
+    InstPtr *m_mi;
+    VBedHPtr *m_vbedh;
+    const SelectionMask *m_selmask;
+    InstPos m_pos_within_model;
+
+public:
+    explicit ArrangeableModelInstance(InstPtr *mi,
+                                      VBedHPtr *vbedh,
+                                      const SelectionMask *selmask,
+                                      const InstPos &pos)
+        : m_mi{mi}, m_vbedh{vbedh}, m_selmask{selmask}, m_pos_within_model{pos}
+    {
+        assert(m_mi != nullptr && m_vbedh != nullptr);
+    }
+
+    // Arrangeable:
+    ObjectID   id() const override { return m_mi->id(); }
+    ObjectID   geometry_id() const override { return m_mi->get_object()->id(); }
+    ExPolygons full_outline() const override;
+    Polygon    convex_outline() const override;
+    bool       is_printable() const override { return m_mi->printable; }
+    bool       is_selected() const override;
+    void       transform(const Vec2d &tr, double rot) override;
+
+    int        get_bed_index() const override { return m_vbedh->get_bed_index(*this); }
+    bool       assign_bed(int bed_idx) override;
+
+    // VBedPlaceable:
+    BoundingBoxf bounding_box() const override { return to_2d(instance_bounding_box(*m_mi)); }
+    void         displace(const Vec2d &transl, double rot) override
+    {
+        if constexpr (!std::is_const_v<InstPtr>)
+            transform_instance(*m_mi, transl, rot);
+    }
+};
+
+extern template class ArrangeableModelInstance<ModelInstance, VirtualBedHandler>;
+extern template class ArrangeableModelInstance<const ModelInstance, const VirtualBedHandler>;
+
+class ArrangeableSLAPrintObject : public Arrangeable
+{
+    const SLAPrintObject *m_po;
+    Arrangeable          *m_arrbl;
+    Transform3d           m_inst_trafo;
+
+public:
+    ArrangeableSLAPrintObject(const SLAPrintObject *po,
+                              Arrangeable *arrbl,
+                              const Transform3d &inst_tr = Transform3d::Identity())
+        : m_po{po}, m_arrbl{arrbl}, m_inst_trafo{inst_tr}
+    {}
+
+    ObjectID id() const override { return m_arrbl->id(); }
+    ObjectID geometry_id() const override { return m_arrbl->geometry_id(); }
+
+    ExPolygons full_outline() const override;
+    ExPolygons full_envelope() const override;
+
+    Polygon convex_outline() const override;
+    Polygon convex_envelope() const override;
+
+    void transform(const Vec2d &transl, double rot) override
+    {
+        m_arrbl->transform(transl, rot);
+    }
+    int  get_bed_index() const override { return m_arrbl->get_bed_index(); }
+    bool assign_bed(int bedidx) override
+    {
+        return m_arrbl->assign_bed(bedidx);
+    }
+
+    bool is_printable() const override { return m_arrbl->is_printable(); }
+    bool is_selected() const override { return m_arrbl->is_selected(); }
+    int  priority() const override { return m_arrbl->priority(); }
+};
+
+class ArrangeableSLAPrint : public ArrangeableSlicerModel {
+    const SLAPrint *m_slaprint;
+
+    friend class SceneBuilder;
+
+    template<class Self, class Fn>
+    static void for_each_arrangeable_(Self &&self, Fn &&fn);
+
+    template<class Self, class Fn>
+    static void visit_arrangeable_(Self &&self, const ObjectID &id, Fn &&fn);
+
+public:
+    explicit ArrangeableSLAPrint(const SLAPrint *slaprint, SceneBuilder &builder)
+        : m_slaprint{slaprint}
+        , ArrangeableSlicerModel{builder}
+    {
+        assert(slaprint != nullptr);
+    }
+
+    void for_each_arrangeable(std::function<void(Arrangeable &)>) override;
+
+    void for_each_arrangeable(
+        std::function<void(const Arrangeable &)>) const override;
+
+    void visit_arrangeable(
+        const ObjectID &id,
+        std::function<void(const Arrangeable &)>) const override;
+
+    void visit_arrangeable(const ObjectID &id,
+                           std::function<void(Arrangeable &)>) override;
+};
+
+template<class Mdl>
+auto find_instance_by_id(Mdl &&model, const ObjectID &id)
+{
+    std::remove_reference_t<
+        decltype(std::declval<Mdl>().objects[0]->instances[0])>
+        ret = nullptr;
+
+    InstPos pos;
+
+    for (auto * obj : model.objects) {
+        for (auto *inst : obj->instances) {
+            if (inst->id() == id) {
+                ret = inst;
+                break;
+            }
+            ++pos.inst_idx;
+        }
+
+        if (ret)
+            break;
+
+        ++pos.obj_idx;
+        pos.inst_idx = 0;
+    }
+
+    return std::make_pair(ret, pos);
+}
+
+struct ModelDuplicate
+{
+    ObjectID id;
+    Vec2d    tr  = Vec2d::Zero();
+    double   rot = 0.;
+    int      bed_idx = Unarranged;
+};
+
+// Implementing the Arrangeable interface with the whole Model being one outline
+// with all its objects and instances.
+template<class Mdl, class Dup, class VBH>
+class ArrangeableFullModel: public Arrangeable, VBedPlaceable
+{
+    Mdl *m_mdl;
+    Dup *m_dup;
+    VBH *m_vbh;
+
+public:
+    explicit ArrangeableFullModel(Mdl *mdl,
+                                  Dup *md,
+                                  VBH *vbh)
+        : m_mdl{mdl}, m_dup{md}, m_vbh{vbh}
+    {
+        assert(m_mdl != nullptr);
+    }
+
+    ObjectID id() const override { return m_dup->id.id + 1; }
+    ObjectID geometry_id() const override;
+
+    ExPolygons full_outline() const override;
+
+    Polygon convex_outline() const override;
+
+    bool is_printable() const override { return true; }
+    bool is_selected() const override { return m_dup->id == 0; }
+
+    int get_bed_index() const override
+    {
+        return m_vbh->get_bed_index(*this);
+    }
+
+    void transform(const Vec2d &tr, double rot) override
+    {
+        if constexpr (!std::is_const_v<Mdl> && !std::is_const_v<Dup>) {
+            m_dup->tr += tr;
+            m_dup->rot += rot;
+        }
+    }
+
+    bool assign_bed(int bed_idx) override
+    {
+        bool ret = false;
+
+        if constexpr (!std::is_const_v<VBH> && !std::is_const_v<Dup>) {
+            if ((ret = m_vbh->assign_bed(*this, bed_idx)))
+                m_dup->bed_idx = bed_idx;
+        }
+
+        return ret;
+    }
+
+    BoundingBoxf bounding_box() const override { return unscaled(get_extents(convex_outline())); }
+    void displace(const Vec2d &transl, double rot) override
+    {
+        transform(transl, rot);
+    }
+};
+
+extern template class ArrangeableFullModel<Model, ModelDuplicate, VirtualBedHandler>;
+extern template class ArrangeableFullModel<const Model, const ModelDuplicate, const VirtualBedHandler>;
+
+class DuplicableModel: public ArrangeableModel {
+    AnyPtr<Model> m_model;
+    AnyPtr<VirtualBedHandler> m_vbh;
+    std::vector<ModelDuplicate> m_duplicates;
+    BoundingBox m_bedbb;
+
+    template<class Self, class Fn>
+    static void visit_arrangeable_(Self &&self, const ObjectID &id, Fn &&fn)
+    {
+        if (id.valid()) {
+            size_t idx = id.id - 1;
+            if (idx < self.m_duplicates.size()) {
+                auto &md = self.m_duplicates[idx];
+                ArrangeableFullModel arrbl{self.m_model.get(), &md, self.m_vbh.get()};
+                fn(arrbl);
+            }
+        }
+    }
+
+public:
+    explicit DuplicableModel(AnyPtr<Model> mdl,
+                             AnyPtr<VirtualBedHandler> vbh,
+                             const BoundingBox &bedbb);
+    ~DuplicableModel();
+
+    void for_each_arrangeable(std::function<void(Arrangeable &)> fn) override
+    {
+        for (ModelDuplicate &md : m_duplicates) {
+            ArrangeableFullModel arrbl{m_model.get(), &md, m_vbh.get()};
+            fn(arrbl);
+        }
+    }
+    void for_each_arrangeable(std::function<void(const Arrangeable&)> fn) const override
+    {
+        for (const ModelDuplicate &md : m_duplicates) {
+            ArrangeableFullModel arrbl{m_model.get(), &md, m_vbh.get()};
+            fn(arrbl);
+        }
+    }
+    void visit_arrangeable(const ObjectID &id, std::function<void(const Arrangeable &)> fn) const override
+    {
+        visit_arrangeable_(*this, id, fn);
+    }
+    void visit_arrangeable(const ObjectID &id, std::function<void(Arrangeable &)> fn) override
+    {
+        visit_arrangeable_(*this, id, fn);
+    }
+
+    ObjectID add_arrangeable(const ObjectID &prototype_id) override;
+
+    void apply_duplicates();
+};
+
+} // namespace arr2
+} // namespace Slic3r
+
+#endif // SCENEBUILDER_HPP

src/libslic3r/Arrange/SegmentedRectangleBed.hpp

@@ -0,0 +1,105 @@
+#ifndef SEGMENTEDRECTANGLEBED_HPP
+#define SEGMENTEDRECTANGLEBED_HPP
+
+#include "libslic3r/Arrange/Core/Beds.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+enum class RectPivots {
+    Center, BottomLeft, BottomRight, TopLeft, TopRight
+};
+
+template<class T> struct IsSegmentedBed_ : public std::false_type {};
+template<class T> constexpr bool IsSegmentedBed = IsSegmentedBed_<StripCVRef<T>>::value;
+
+template<class SegX = void, class SegY = void, class Pivot = void>
+struct SegmentedRectangleBed {
+    Vec<2, size_t> segments = Vec<2, size_t>::Ones();
+    BoundingBox bb;
+    RectPivots pivot = RectPivots::Center;
+
+    SegmentedRectangleBed() = default;
+    SegmentedRectangleBed(const BoundingBox &bb,
+                          size_t segments_x,
+                          size_t segments_y,
+                          const RectPivots pivot = RectPivots::Center)
+        : segments{segments_x, segments_y}, bb{bb}, pivot{pivot}
+    {}
+
+    size_t segments_x() const noexcept { return segments.x(); }
+    size_t segments_y() const noexcept { return segments.y(); }
+
+    auto alignment() const noexcept { return pivot; }
+};
+
+template<size_t SegX, size_t SegY>
+struct SegmentedRectangleBed<std::integral_constant<size_t, SegX>,
+                             std::integral_constant<size_t, SegY>>
+{
+    BoundingBox bb;
+    RectPivots pivot = RectPivots::Center;
+
+    SegmentedRectangleBed() = default;
+
+    explicit SegmentedRectangleBed(const BoundingBox &b,
+                                   const RectPivots pivot = RectPivots::Center)
+        : bb{b}
+    {}
+
+    size_t segments_x() const noexcept { return SegX; }
+    size_t segments_y() const noexcept { return SegY; }
+
+    auto alignment() const noexcept { return pivot; }
+};
+
+template<size_t SegX, size_t SegY, RectPivots pivot>
+struct SegmentedRectangleBed<std::integral_constant<size_t, SegX>,
+                             std::integral_constant<size_t, SegY>,
+                             std::integral_constant<RectPivots, pivot>>
+{
+    BoundingBox bb;
+
+    SegmentedRectangleBed() = default;
+
+    explicit SegmentedRectangleBed(const BoundingBox &b) : bb{b} {}
+
+    size_t segments_x() const noexcept { return SegX; }
+    size_t segments_y() const noexcept { return SegY; }
+
+    auto alignment() const noexcept { return pivot; }
+};
+
+template<class... Args>
+struct IsSegmentedBed_<SegmentedRectangleBed<Args...>>
+    : public std::true_type {};
+
+template<class... Args>
+auto offset(const SegmentedRectangleBed<Args...> &bed, coord_t val_scaled)
+{
+    auto cpy = bed;
+    cpy.bb.offset(val_scaled);
+
+    return cpy;
+}
+
+template<class...Args>
+auto bounding_box(const SegmentedRectangleBed<Args...> &bed)
+{
+    return bed.bb;
+}
+
+template<class...Args>
+auto area(const SegmentedRectangleBed<Args...> &bed)
+{
+    return arr2::area(bed.bb);
+}
+
+template<class...Args>
+ExPolygons to_expolygons(const SegmentedRectangleBed<Args...> &bed)
+{
+    return to_expolygons(RectangleBed{bed.bb});
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // SEGMENTEDRECTANGLEBED_HPP

src/libslic3r/Arrange/Tasks/ArrangeTask.hpp

@@ -0,0 +1,81 @@
+#ifndef ARRANGETASK_HPP
+#define ARRANGETASK_HPP
+
+#include "libslic3r/Arrange/Arrange.hpp"
+#include "libslic3r/Arrange/Items/TrafoOnlyArrangeItem.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+struct ArrangeTaskResult : public ArrangeResult
+{
+    std::vector<TrafoOnlyArrangeItem> items;
+
+    bool apply_on(ArrangeableModel &mdl) override
+    {
+        bool ret = true;
+        for (auto &itm : items) {
+            if (is_arranged(itm))
+                ret = ret && apply_arrangeitem(itm, mdl);
+        }
+
+        return ret;
+    }
+
+    template<class ArrItem>
+    void add_item(const ArrItem &itm)
+    {
+        items.emplace_back(itm);
+        if (auto id = retrieve_id(itm))
+            imbue_id(items.back(), *id);
+    }
+
+    template<class It>
+    void add_items(const Range<It> &items_range)
+    {
+        for (auto &itm : items_range)
+            add_item(itm);
+    }
+};
+
+template<class ArrItem> struct ArrangeTask : public ArrangeTaskBase
+{
+    struct ArrangeSet
+    {
+        std::vector<ArrItem> selected, unselected;
+    } printable, unprintable;
+
+    ExtendedBed     bed;
+    ArrangeSettings settings;
+
+    static std::unique_ptr<ArrangeTask> create(
+        const Scene                        &sc,
+        const ArrangeableToItemConverter<ArrItem> &converter);
+
+    static std::unique_ptr<ArrangeTask> create(const Scene &sc)
+    {
+        auto conv = ArrangeableToItemConverter<ArrItem>::create(sc);
+        return create(sc, *conv);
+    }
+
+    std::unique_ptr<ArrangeResult> process(Ctl &ctl) override
+    {
+        return process_native(ctl);
+    }
+
+    std::unique_ptr<ArrangeTaskResult> process_native(Ctl &ctl);
+    std::unique_ptr<ArrangeTaskResult> process_native(Ctl &&ctl)
+    {
+        return process_native(ctl);
+    }
+
+    int item_count_to_process() const override
+    {
+        return static_cast<int>(printable.selected.size() +
+                                unprintable.selected.size());
+    }
+};
+
+} // namespace arr2
+} // namespace Slic3r
+
+#endif // ARRANGETASK_HPP

src/libslic3r/Arrange/Tasks/ArrangeTaskImpl.hpp

@@ -0,0 +1,158 @@
+#ifndef ARRANGETASK_IMPL_HPP
+#define ARRANGETASK_IMPL_HPP
+
+#include <random>
+
+#include <boost/log/trivial.hpp>
+
+#include "ArrangeTask.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+// Prepare the selected and unselected items separately. If nothing is
+// selected, behaves as if everything would be selected.
+template<class ArrItem>
+void extract_selected(ArrangeTask<ArrItem> &task,
+                      const ArrangeableModel &mdl,
+                      const ArrangeableToItemConverter<ArrItem> &itm_conv)
+{
+    // Go through the objects and check if inside the selection
+    mdl.for_each_arrangeable(
+        [&task, &itm_conv](const Arrangeable &arrbl) {
+            bool selected = arrbl.is_selected();
+            bool printable = arrbl.is_printable();
+
+            try {
+                auto itm = itm_conv.convert(arrbl, selected ? 0 : -SCALED_EPSILON);
+
+                auto &container_parent = printable ? task.printable :
+                                                 task.unprintable;
+
+                auto &container = selected ?
+                                       container_parent.selected :
+                                       container_parent.unselected;
+
+                container.emplace_back(std::move(itm));
+            } catch (const EmptyItemOutlineError &ex) {
+                BOOST_LOG_TRIVIAL(error)
+                    << "ObjectID " << std::to_string(arrbl.id().id) << ": " << ex.what();
+            }
+        });
+
+    // If the selection was empty arrange everything
+    if (task.printable.selected.empty() && task.unprintable.selected.empty()) {
+        task.printable.selected.swap(task.printable.unselected);
+        task.unprintable.selected.swap(task.unprintable.unselected);
+    }
+}
+
+template<class ArrItem>
+std::unique_ptr<ArrangeTask<ArrItem>> ArrangeTask<ArrItem>::create(
+    const Scene &sc, const ArrangeableToItemConverter<ArrItem> &converter)
+{
+    auto task = std::make_unique<ArrangeTask<ArrItem>>();
+
+    task->settings.set_from(sc.settings());
+
+    task->bed = get_corrected_bed(sc.bed(), converter);
+
+    extract_selected(*task, sc.model(), converter);
+
+    return task;
+}
+
+// Remove all items on the physical bed (not occupyable for unprintable items)
+// and shift all items to the next lower bed index, so that arrange will think
+// that logical bed no. 1 is the physical one
+template<class ItemCont>
+void prepare_fixed_unselected(ItemCont &items, int shift)
+{
+    for (auto &itm : items)
+        set_bed_index(itm, get_bed_index(itm) - shift);
+
+    items.erase(std::remove_if(items.begin(), items.end(),
+                               [](auto &itm) { return !is_arranged(itm); }),
+                items.end());
+}
+
+inline int find_first_empty_bed(const std::vector<int>& bed_indices,
+                                int starting_from = 0) {
+    int ret = starting_from;
+
+    for (int idx : bed_indices) {
+        if (idx == ret) {
+            ret++;
+        } else if (idx > ret) {
+            break;
+        }
+    }
+
+    return ret;
+}
+
+template<class ArrItem>
+std::unique_ptr<ArrangeTaskResult>
+ArrangeTask<ArrItem>::process_native(Ctl &ctl)
+{
+    auto result = std::make_unique<ArrangeTaskResult>();
+
+    auto arranger = Arranger<ArrItem>::create(settings);
+
+    class TwoStepArrangeCtl: public Ctl
+    {
+        Ctl &parent;
+        ArrangeTask &self;
+    public:
+        TwoStepArrangeCtl(Ctl &p, ArrangeTask &slf) : parent{p}, self{slf} {}
+
+        void update_status(int remaining) override
+        {
+            parent.update_status(remaining + self.unprintable.selected.size());
+        }
+
+        bool was_canceled() const override { return parent.was_canceled(); }
+
+    } subctl{ctl, *this};
+
+    auto fixed_items = printable.unselected;
+
+    // static (unselected) unprintable objects should not be overlapped by
+    // movable and printable objects
+    std::copy(unprintable.unselected.begin(),
+              unprintable.unselected.end(),
+              std::back_inserter(fixed_items));
+
+    arranger->arrange(printable.selected, fixed_items, bed, subctl);
+
+    std::vector<int> printable_bed_indices =
+        get_bed_indices(crange(printable.selected), crange(printable.unselected));
+
+    // If there are no printables, leave the physical bed empty
+    constexpr int SearchFrom = 1;
+
+    // Unprintable items should go to the first logical (!) bed not containing
+    // any printable items
+    int first_empty_bed = find_first_empty_bed(printable_bed_indices, SearchFrom);
+
+    prepare_fixed_unselected(unprintable.unselected, first_empty_bed);
+
+    arranger->arrange(unprintable.selected, unprintable.unselected, bed, ctl);
+
+    result->add_items(crange(printable.selected));
+
+    for (auto &itm : unprintable.selected) {
+        if (is_arranged(itm)) {
+            int bedidx = get_bed_index(itm) + first_empty_bed;
+            arr2::set_bed_index(itm, bedidx);
+        }
+
+        result->add_item(itm);
+    }
+
+    return result;
+}
+
+} // namespace arr2
+} // namespace Slic3r
+
+#endif //ARRANGETASK_IMPL_HPP

src/libslic3r/Arrange/Tasks/FillBedTask.hpp

@@ -0,0 +1,53 @@
+#ifndef FILLBEDTASK_HPP
+#define FILLBEDTASK_HPP
+
+#include "MultiplySelectionTask.hpp"
+
+#include "libslic3r/Arrange/Arrange.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+struct FillBedTaskResult: public MultiplySelectionTaskResult {};
+
+template<class ArrItem>
+struct FillBedTask: public ArrangeTaskBase
+{
+    std::optional<ArrItem> prototype_item;
+
+    std::vector<ArrItem> selected, unselected;
+
+    ArrangeSettings settings;
+    ExtendedBed bed;
+    size_t selected_existing_count = 0;
+
+    std::unique_ptr<FillBedTaskResult> process_native(Ctl &ctl);
+    std::unique_ptr<FillBedTaskResult> process_native(Ctl &&ctl)
+    {
+        return process_native(ctl);
+    }
+
+    std::unique_ptr<ArrangeResult> process(Ctl &ctl) override
+    {
+        return process_native(ctl);
+    }
+
+    int item_count_to_process() const override
+    {
+        return selected.size();
+    }
+
+    static std::unique_ptr<FillBedTask> create(
+        const Scene &sc,
+        const ArrangeableToItemConverter<ArrItem> &converter);
+
+    static std::unique_ptr<FillBedTask> create(const Scene &sc)
+    {
+        auto conv = ArrangeableToItemConverter<ArrItem>::create(sc);
+        return create(sc, *conv);
+    }
+};
+
+} // namespace arr2
+} // namespace Slic3r
+
+#endif // FILLBEDTASK_HPP

src/libslic3r/Arrange/Tasks/FillBedTaskImpl.hpp

@@ -0,0 +1,201 @@
+#ifndef FILLBEDTASKIMPL_HPP
+#define FILLBEDTASKIMPL_HPP
+
+#include "FillBedTask.hpp"
+
+#include "Arrange/Core/NFP/NFPArrangeItemTraits.hpp"
+
+#include <boost/log/trivial.hpp>
+
+namespace Slic3r { namespace arr2 {
+
+template<class ArrItem>
+int calculate_items_needed_to_fill_bed(const ExtendedBed &bed,
+                                       const ArrItem &prototype_item,
+                                       size_t prototype_count,
+                                       const std::vector<ArrItem> &fixed)
+{
+    double poly_area  = fixed_area(prototype_item);
+
+    auto area_sum_fn = [](double s, const auto &itm) {
+        return s + (get_bed_index(itm) == 0) * fixed_area(itm);
+    };
+
+    double unsel_area = std::accumulate(fixed.begin(),
+                                        fixed.end(),
+                                        0.,
+                                        area_sum_fn);
+
+    double fixed_area = unsel_area + prototype_count * poly_area;
+    double bed_area   = 0.;
+
+    visit_bed([&bed_area] (auto &realbed) { bed_area = area(realbed); }, bed);
+
+    // This is the maximum number of items,
+    // the real number will always be close but less.
+    auto needed_items = static_cast<int>(
+        std::ceil((bed_area - fixed_area) / poly_area));
+
+    return needed_items;
+}
+
+template<class ArrItem>
+void extract(FillBedTask<ArrItem> &task,
+             const Scene &scene,
+             const ArrangeableToItemConverter<ArrItem> &itm_conv)
+{
+    task.prototype_item = {};
+
+    auto selected_ids = scene.selected_ids();
+
+    if (selected_ids.empty())
+        return;
+
+    std::set<ObjectID> selected_objects = selected_geometry_ids(scene);
+
+    if (selected_objects.size() != 1)
+        return;
+
+    ObjectID prototype_geometry_id = *(selected_objects.begin());
+
+    auto set_prototype_item = [&task, &itm_conv](const Arrangeable &arrbl) {
+        if (arrbl.is_printable())
+            task.prototype_item = itm_conv.convert(arrbl);
+    };
+
+    scene.model().visit_arrangeable(selected_ids.front(), set_prototype_item);
+
+    if (!task.prototype_item)
+        return;
+
+    // Workaround for missing items when arranging the same geometry only:
+    // Injecting a number of items but with slightly shrinked shape, so that
+    // they can fill the emerging holes. Priority is set to lowest so that
+    // these filler items will only be inserted as the last ones.
+    ArrItem prototype_item_shrinked;
+    scene.model().visit_arrangeable(selected_ids.front(),
+        [&prototype_item_shrinked, &itm_conv](const Arrangeable &arrbl) {
+            if (arrbl.is_printable())
+                prototype_item_shrinked = itm_conv.convert(arrbl, -SCALED_EPSILON);
+        });
+
+    set_bed_index(*task.prototype_item, Unarranged);
+
+    auto collect_task_items = [&prototype_geometry_id, &task,
+                               &itm_conv](const Arrangeable &arrbl) {
+        try {
+            if (arrbl.geometry_id() == prototype_geometry_id) {
+                if (arrbl.is_printable()) {
+                    auto itm = itm_conv.convert(arrbl);
+                    raise_priority(itm);
+                    task.selected.emplace_back(std::move(itm));
+                }
+            } else {
+                auto itm = itm_conv.convert(arrbl, -SCALED_EPSILON);
+                task.unselected.emplace_back(std::move(itm));
+            }
+        } catch (const EmptyItemOutlineError &ex) {
+            BOOST_LOG_TRIVIAL(error)
+                << "ObjectID " << std::to_string(arrbl.id().id) << ": " << ex.what();
+        }
+    };
+
+    // Set the lowest priority to the shrinked prototype (hole filler) item
+    set_priority(prototype_item_shrinked,
+                 lowest_priority(range(task.selected)) - 1);
+
+    scene.model().for_each_arrangeable(collect_task_items);
+
+    int needed_items = calculate_items_needed_to_fill_bed(task.bed,
+                                                          *task.prototype_item,
+                                                          task.selected.size(),
+                                                          task.unselected);
+
+    task.selected_existing_count = task.selected.size();
+    task.selected.reserve(task.selected.size() + needed_items);
+    std::fill_n(std::back_inserter(task.selected), needed_items,
+                *task.prototype_item);
+
+    // Add as many filler items as there are needed items. Most of them will
+    // be discarded anyways.
+    std::fill_n(std::back_inserter(task.selected), needed_items,
+                prototype_item_shrinked);
+}
+
+
+template<class ArrItem>
+std::unique_ptr<FillBedTask<ArrItem>> FillBedTask<ArrItem>::create(
+    const Scene &sc, const ArrangeableToItemConverter<ArrItem> &converter)
+{
+    auto task = std::make_unique<FillBedTask<ArrItem>>();
+
+    task->settings.set_from(sc.settings());
+
+    task->bed = get_corrected_bed(sc.bed(), converter);
+
+    extract(*task, sc, converter);
+
+    return task;
+}
+
+template<class ArrItem>
+std::unique_ptr<FillBedTaskResult> FillBedTask<ArrItem>::process_native(
+    Ctl &ctl)
+{
+    auto result = std::make_unique<FillBedTaskResult>();
+
+    if (!prototype_item)
+        return result;
+
+    result->prototype_id = retrieve_id(*prototype_item).value_or(ObjectID{});
+
+    class FillBedCtl: public ArrangerCtl<ArrItem>
+    {
+        ArrangeTaskCtl &parent;
+        FillBedTask &self;
+        bool do_stop = false;
+
+    public:
+        FillBedCtl(ArrangeTaskCtl &p, FillBedTask &slf) : parent{p}, self{slf} {}
+
+        void update_status(int remaining) override
+        {
+            parent.update_status(remaining);
+        }
+
+        bool was_canceled() const override
+        {
+            return parent.was_canceled() || do_stop;
+        }
+
+        void on_packed(ArrItem &itm) override
+        {
+            // Stop at the first filler that is not on the physical bed
+            do_stop = get_bed_index(itm) > PhysicalBedId && get_priority(itm) < 0;
+        }
+
+    } subctl(ctl, *this);
+
+    auto arranger = Arranger<ArrItem>::create(settings);
+
+    arranger->arrange(selected, unselected, bed, subctl);
+
+    auto arranged_range = Range{selected.begin(),
+                                selected.begin() + selected_existing_count};
+
+    result->add_arranged_items(arranged_range);
+
+    auto to_add_range = Range{selected.begin() + selected_existing_count,
+                              selected.end()};
+
+    for (auto &itm : to_add_range)
+        if (get_bed_index(itm) == PhysicalBedId)
+            result->add_new_item(itm);
+
+    return result;
+}
+
+} // namespace arr2
+} // namespace Slic3r
+
+#endif // FILLBEDTASKIMPL_HPP

src/libslic3r/Arrange/Tasks/MultiplySelectionTask.hpp

@@ -0,0 +1,108 @@
+#ifndef MULTIPLYSELECTIONTASK_HPP
+#define MULTIPLYSELECTIONTASK_HPP
+
+#include "libslic3r/Arrange/Arrange.hpp"
+#include "libslic3r/Arrange/Items/TrafoOnlyArrangeItem.hpp"
+
+namespace Slic3r { namespace arr2 {
+
+struct MultiplySelectionTaskResult: public ArrangeResult {
+    ObjectID prototype_id;
+
+    std::vector<TrafoOnlyArrangeItem> arranged_items;
+    std::vector<TrafoOnlyArrangeItem> to_add;
+
+    bool apply_on(ArrangeableModel &mdl) override
+    {
+        bool ret = prototype_id.valid();
+
+        if (!ret)
+            return ret;
+
+        for (auto &itm : to_add) {
+            auto id = mdl.add_arrangeable(prototype_id);
+            imbue_id(itm, id);
+            ret = ret && apply_arrangeitem(itm, mdl);
+        }
+
+        for (auto &itm : arranged_items) {
+            if (is_arranged(itm))
+                ret = ret && apply_arrangeitem(itm, mdl);
+        }
+
+        return ret;
+    }
+
+    template<class ArrItem>
+    void add_arranged_item(const ArrItem &itm)
+    {
+        arranged_items.emplace_back(itm);
+        if (auto id = retrieve_id(itm))
+            imbue_id(arranged_items.back(), *id);
+    }
+
+    template<class It>
+    void add_arranged_items(const Range<It> &items_range)
+    {
+        arranged_items.reserve(items_range.size());
+        for (auto &itm : items_range)
+            add_arranged_item(itm);
+    }
+
+    template<class ArrItem> void add_new_item(const ArrItem &itm)
+    {
+        to_add.emplace_back(itm);
+    }
+
+    template<class It> void add_new_items(const Range<It> &items_range)
+    {
+        to_add.reserve(items_range.size());
+        for (auto &itm : items_range) {
+            to_add.emplace_back(itm);
+        }
+    }
+};
+
+template<class ArrItem>
+struct MultiplySelectionTask: public ArrangeTaskBase
+{
+    std::optional<ArrItem> prototype_item;
+
+    std::vector<ArrItem> selected, unselected;
+
+    ArrangeSettings settings;
+    ExtendedBed bed;
+    size_t selected_existing_count = 0;
+
+    std::unique_ptr<MultiplySelectionTaskResult> process_native(Ctl &ctl);
+    std::unique_ptr<MultiplySelectionTaskResult> process_native(Ctl &&ctl)
+    {
+        return process_native(ctl);
+    }
+
+    std::unique_ptr<ArrangeResult> process(Ctl &ctl) override
+    {
+        return process_native(ctl);
+    }
+
+    int item_count_to_process() const override
+    {
+        return selected.size();
+    }
+
+    static std::unique_ptr<MultiplySelectionTask> create(
+        const Scene &sc,
+        size_t multiply_count,
+        const ArrangeableToItemConverter<ArrItem> &converter);
+
+    static std::unique_ptr<MultiplySelectionTask> create(const Scene &sc,
+                                                         size_t multiply_count)
+    {
+        auto conv = ArrangeableToItemConverter<ArrItem>::create(sc);
+        return create(sc, multiply_count, *conv);
+    }
+};
+
+}} // namespace Slic3r::arr2
+
+#endif // MULTIPLYSELECTIONTASK_HPP

src/libslic3r/Arrange/Tasks/MultiplySelectionTaskImpl.hpp

@@ -0,0 +1,127 @@
+#ifndef MULTIPLYSELECTIONTASKIMPL_HPP
+#define MULTIPLYSELECTIONTASKIMPL_HPP
+
+#include "MultiplySelectionTask.hpp"
+
+#include <boost/log/trivial.hpp>
+
+namespace Slic3r { namespace arr2 {
+
+template<class ArrItem>
+std::unique_ptr<MultiplySelectionTask<ArrItem>> MultiplySelectionTask<ArrItem>::create(
+    const Scene &scene, size_t count, const ArrangeableToItemConverter<ArrItem> &itm_conv)
+{
+    auto task_ptr = std::make_unique<MultiplySelectionTask<ArrItem>>();
+
+    auto &task = *task_ptr;
+
+    task.settings.set_from(scene.settings());
+
+    task.bed = get_corrected_bed(scene.bed(), itm_conv);
+
+    task.prototype_item = {};
+
+    auto selected_ids = scene.selected_ids();
+
+    if (selected_ids.empty())
+        return task_ptr;
+
+    std::set<ObjectID> selected_objects = selected_geometry_ids(scene);
+
+    if (selected_objects.size() != 1)
+        return task_ptr;
+
+    ObjectID prototype_geometry_id = *(selected_objects.begin());
+
+    auto set_prototype_item = [&task, &itm_conv](const Arrangeable &arrbl) {
+        if (arrbl.is_printable())
+            task.prototype_item = itm_conv.convert(arrbl);
+    };
+
+    scene.model().visit_arrangeable(selected_ids.front(), set_prototype_item);
+
+    if (!task.prototype_item)
+        return task_ptr;
+
+    set_bed_index(*task.prototype_item, Unarranged);
+
+    auto collect_task_items = [&prototype_geometry_id, &task,
+                               &itm_conv](const Arrangeable &arrbl) {
+        try {
+            if (arrbl.geometry_id() == prototype_geometry_id) {
+                if (arrbl.is_printable()) {
+                    auto itm = itm_conv.convert(arrbl);
+                    raise_priority(itm);
+                    task.selected.emplace_back(std::move(itm));
+                }
+            } else {
+                auto itm = itm_conv.convert(arrbl, -SCALED_EPSILON);
+                task.unselected.emplace_back(std::move(itm));
+            }
+        } catch (const EmptyItemOutlineError &ex) {
+            BOOST_LOG_TRIVIAL(error)
+                << "ObjectID " << std::to_string(arrbl.id().id) << ": " << ex.what();
+        }
+    };
+
+    scene.model().for_each_arrangeable(collect_task_items);
+
+    task.selected_existing_count = task.selected.size();
+    task.selected.reserve(task.selected.size() + count);
+    std::fill_n(std::back_inserter(task.selected), count, *task.prototype_item);
+
+    return task_ptr;
+}
+
+template<class ArrItem>
+std::unique_ptr<MultiplySelectionTaskResult>
+MultiplySelectionTask<ArrItem>::process_native(Ctl &ctl)
+{
+    auto result = std::make_unique<MultiplySelectionTaskResult>();
+
+    if (!prototype_item)
+        return result;
+
+    result->prototype_id = retrieve_id(*prototype_item).value_or(ObjectID{});
+
+    class MultiplySelectionCtl: public ArrangerCtl<ArrItem>
+    {
+        ArrangeTaskCtl &parent;
+        MultiplySelectionTask<ArrItem> &self;
+
+    public:
+        MultiplySelectionCtl(ArrangeTaskCtl &p, MultiplySelectionTask<ArrItem> &slf)
+            : parent{p}, self{slf} {}
+
+        void update_status(int remaining) override
+        {
+            parent.update_status(remaining);
+        }
+
+        bool was_canceled() const override
+        {
+            return parent.was_canceled();
+        }
+
+    } subctl(ctl, *this);
+
+    auto arranger = Arranger<ArrItem>::create(settings);
+
+    arranger->arrange(selected, unselected, bed, subctl);
+
+    auto arranged_range = Range{selected.begin(),
+                                selected.begin() + selected_existing_count};
+
+    result->add_arranged_items(arranged_range);
+
+    auto to_add_range = Range{selected.begin() + selected_existing_count,
+                              selected.end()};
+
+    result->add_new_items(to_add_range);
+
+    return result;
+}
+
+}} // namespace Slic3r::arr2
+
+#endif // MULTIPLYSELECTIONTASKIMPL_HPP

src/libslic3r/BoostAdapter.hpp

@@ -3,6 +3,8 @@
 
 #include <libslic3r/Point.hpp>
 #include <libslic3r/BoundingBox.hpp>
+#include <libslic3r/ExPolygon.hpp>
+#include <libslic3r/Polyline.hpp>
 
 #include <boost/geometry.hpp>
 
@@ -126,13 +128,146 @@ struct indexed_access<BB3<T>, 1, d> {
     }
 };
 
-}
-}
+
+/* ************************************************************************** */
+/* Segment concept adaptaion ************************************************ */
+/* ************************************************************************** */
+
+template<> struct tag<Slic3r::Line> {
+    using type = segment_tag;
+};
+
+template<> struct point_type<Slic3r::Line> {
+    using type = Slic3r::Point;
+};
+
+template<> struct indexed_access<Slic3r::Line, 0, 0> {
+    static inline coord_t get(Slic3r::Line const& l) { return l.a.x(); }
+    static inline void set(Slic3r::Line &l, coord_t c) { l.a.x() = c; }
+};
+
+template<> struct indexed_access<Slic3r::Line, 0, 1> {
+    static inline coord_t get(Slic3r::Line const& l) { return l.a.y(); }
+    static inline void set(Slic3r::Line &l, coord_t c) { l.a.y() = c; }
+};
+
+template<> struct indexed_access<Slic3r::Line, 1, 0> {
+    static inline coord_t get(Slic3r::Line const& l) { return l.b.x(); }
+    static inline void set(Slic3r::Line &l, coord_t c) { l.b.x() = c; }
+};
+
+template<> struct indexed_access<Slic3r::Line, 1, 1> {
+    static inline coord_t get(Slic3r::Line const& l) { return l.b.y(); }
+    static inline void set(Slic3r::Line &l, coord_t c) { l.b.y() = c; }
+};
+
+/* ************************************************************************** */
+/* Polyline concept adaptation ********************************************** */
+/* ************************************************************************** */
+
+template<> struct tag<Slic3r::Polyline> {
+    using type = linestring_tag;
+};
+
+/* ************************************************************************** */
+/* Polygon concept adaptation *********************************************** */
+/* ************************************************************************** */
+
+// Ring implementation /////////////////////////////////////////////////////////
+
+// Boost would refer to ClipperLib::Path (alias Slic3r::ExPolygon) as a ring
+template<> struct tag<Slic3r::Polygon> {
+    using type = ring_tag;
+};
+
+template<> struct point_order<Slic3r::Polygon> {
+    static const order_selector value = counterclockwise;
+};
+
+// All our Paths should be closed for the bin packing application
+template<> struct closure<Slic3r::Polygon> {
+    static const constexpr closure_selector value = closure_selector::open;
+};
+
+// Polygon implementation //////////////////////////////////////////////////////
+
+template<> struct tag<Slic3r::ExPolygon> {
+    using type = polygon_tag;
+};
+
+template<> struct exterior_ring<Slic3r::ExPolygon> {
+    static inline Slic3r::Polygon& get(Slic3r::ExPolygon& p)
+    {
+        return p.contour;
+    }
+    static inline Slic3r::Polygon const& get(Slic3r::ExPolygon const& p)
+    {
+        return p.contour;
+    }
+};
+
+template<> struct ring_const_type<Slic3r::ExPolygon> {
+    using type = const Slic3r::Polygon&;
+};
+
+template<> struct ring_mutable_type<Slic3r::ExPolygon> {
+    using type = Slic3r::Polygon&;
+};
+
+template<> struct interior_const_type<Slic3r::ExPolygon> {
+    using type = const Slic3r::Polygons&;
+};
+
+template<> struct interior_mutable_type<Slic3r::ExPolygon> {
+    using type = Slic3r::Polygons&;
+};
+
+template<>
+struct interior_rings<Slic3r::ExPolygon> {
+
+    static inline Slic3r::Polygons& get(Slic3r::ExPolygon& p) { return p.holes; }
+
+    static inline const Slic3r::Polygons& get(Slic3r::ExPolygon const& p)
+    {
+        return p.holes;
+    }
+};
+
+/* ************************************************************************** */
+/* MultiPolygon concept adaptation ****************************************** */
+/* ************************************************************************** */
+
+template<> struct tag<Slic3r::ExPolygons> {
+    using type = multi_polygon_tag;
+};
+
+}} // namespace geometry::traits
 
 template<> struct range_value<std::vector<Slic3r::Vec2d>> {
     using type = Slic3r::Vec2d;
 };
 
+template<>
+struct range_value<Slic3r::Polyline> {
+    using type = Slic3r::Point;
+};
+
+// This is an addition to the ring implementation of Polygon concept
+template<>
+struct range_value<Slic3r::Polygon> {
+    using type = Slic3r::Point;
+};
+
+template<>
+struct range_value<Slic3r::Polygons> {
+    using type = Slic3r::Polygon;
+};
+
+template<>
+struct range_value<Slic3r::ExPolygons> {
+    using type = Slic3r::ExPolygon;
+};
+
 } // namespace boost
 
 #endif // SLABOOSTADAPTER_HPP

src/libslic3r/BoundingBox.hpp

@@ -54,8 +54,8 @@ public:
         return ! (this->max.x() < other.min.x() || this->min.x() > other.max.x() ||
                   this->max.y() < other.min.y() || this->min.y() > other.max.y());
     }
-    bool operator==(const BoundingBoxBase<PointType, PointsType> &rhs) { return this->min == rhs.min && this->max == rhs.max; }
-    bool operator!=(const BoundingBoxBase<PointType, PointsType> &rhs) { return ! (*this == rhs); }
+    bool operator==(const BoundingBoxBase<PointType, PointsType> &rhs) const noexcept { return this->min == rhs.min && this->max == rhs.max; }
+    bool operator!=(const BoundingBoxBase<PointType, PointsType> &rhs) const noexcept { return ! (*this == rhs); }
 
 private:
     // to access construct()
@@ -192,6 +192,7 @@ public:
     
     BoundingBox() : BoundingBoxBase<Point, Points>() {}
     BoundingBox(const Point &pmin, const Point &pmax) : BoundingBoxBase<Point, Points>(pmin, pmax) {}
+    BoundingBox(const BoundingBoxBase<Vec2crd> &bb): BoundingBox(bb.min, bb.max) {}
     BoundingBox(const Points &points) : BoundingBoxBase<Point, Points>(points) {}
 
     BoundingBox inflated(coordf_t delta) const throw() { BoundingBox out(*this); out.offset(delta); return out; }
@@ -215,6 +216,7 @@ public:
     BoundingBoxf() : BoundingBoxBase<Vec2d>() {}
     BoundingBoxf(const Vec2d &pmin, const Vec2d &pmax) : BoundingBoxBase<Vec2d>(pmin, pmax) {}
     BoundingBoxf(const std::vector<Vec2d> &points) : BoundingBoxBase<Vec2d>(points) {}
+    BoundingBoxf(const BoundingBoxBase<Vec2d> &bb): BoundingBoxf{bb.min, bb.max} {}
 };
 
 class BoundingBoxf3 : public BoundingBox3Base<Vec3d> 
@@ -239,17 +241,23 @@ inline bool empty(const BoundingBox3Base<PointType> &bb)
 
 inline BoundingBox scaled(const BoundingBoxf &bb) { return {scaled(bb.min), scaled(bb.max)}; }
 
-template<class T = coord_t>
-BoundingBoxBase<Vec<2, T>> scaled(const BoundingBoxf &bb) { return {scaled<T>(bb.min), scaled<T>(bb.max)}; }
+template<class T = coord_t, class Tin>
+BoundingBoxBase<Vec<2, T>> scaled(const BoundingBoxBase<Vec<2, Tin>> &bb) { return {scaled<T>(bb.min), scaled<T>(bb.max)}; }
 
 template<class T = coord_t>
-BoundingBox3Base<Vec<3, T>> scaled(const BoundingBoxf3 &bb) { return {scaled<T>(bb.min), scaled<T>(bb.max)}; }
+BoundingBoxBase<Vec<2, T>> scaled(const BoundingBox &bb) { return {scaled<T>(bb.min), scaled<T>(bb.max)}; }
+
+template<class T = coord_t, class Tin>
+BoundingBox3Base<Vec<3, T>> scaled(const BoundingBox3Base<Vec<3, Tin>> &bb) { return {scaled<T>(bb.min), scaled<T>(bb.max)}; }
+
+template<class T = double, class Tin>
+BoundingBoxBase<Vec<2, T>> unscaled(const BoundingBoxBase<Vec<2, Tin>> &bb) { return {unscaled<T>(bb.min), unscaled<T>(bb.max)}; }
 
 template<class T = double>
 BoundingBoxBase<Vec<2, T>> unscaled(const BoundingBox &bb) { return {unscaled<T>(bb.min), unscaled<T>(bb.max)}; }
 
-template<class T = double>
-BoundingBox3Base<Vec<3, T>> unscaled(const BoundingBox3 &bb) { return {unscaled<T>(bb.min), unscaled<T>(bb.max)}; }
+template<class T = double, class Tin>
+BoundingBox3Base<Vec<3, T>> unscaled(const BoundingBox3Base<Vec<3, Tin>> &bb) { return {unscaled<T>(bb.min), unscaled<T>(bb.max)}; }
 
 template<class Tout, class Tin>
 auto cast(const BoundingBoxBase<Tin> &b)
@@ -298,6 +306,19 @@ inline double bbox_point_distance_squared(const BoundingBox &bbox, const Point &
                                    coord_t(0));
 }
 
+template<class T>
+BoundingBoxBase<Vec<2, T>> to_2d(const BoundingBox3Base<Vec<3, T>> &bb)
+{
+    return {to_2d(bb.min), to_2d(bb.max)};
+}
+
+template<class Tout, class T>
+BoundingBoxBase<Vec<2, Tout>> to_2d(const BoundingBox3Base<Vec<3, T>> &bb)
+{
+    return {to_2d(bb.min), to_2d(bb.max)};
+}
+
+
 } // namespace Slic3r
 
 // Serialization through the Cereal library

src/libslic3r/CMakeLists.txt

@@ -203,6 +203,8 @@ set(SLIC3R_SOURCES
     BlacklistedLibraryCheck.hpp
     LocalesUtils.cpp
     LocalesUtils.hpp
+    CutUtils.cpp
+    CutUtils.hpp
     Model.cpp
     Model.hpp
     ModelArrange.hpp
@@ -216,8 +218,55 @@ set(SLIC3R_SOURCES
     MeasureUtils.hpp
     CustomGCode.cpp
     CustomGCode.hpp
-    Arrange.hpp
-    Arrange.cpp
+    Arrange/Arrange.hpp
+    Arrange/ArrangeImpl.hpp
+    Arrange/Items/ArrangeItem.hpp
+    Arrange/Items/ArrangeItem.cpp
+    Arrange/Items/SimpleArrangeItem.hpp
+    Arrange/Items/SimpleArrangeItem.cpp
+    Arrange/Items/TrafoOnlyArrangeItem.hpp
+    Arrange/Items/MutableItemTraits.hpp
+    Arrange/Items/ArbitraryDataStore.hpp
+    Arrange/ArrangeSettingsView.hpp
+    Arrange/ArrangeSettingsDb_AppCfg.hpp
+    Arrange/ArrangeSettingsDb_AppCfg.cpp
+    Arrange/Scene.hpp
+    Arrange/Scene.cpp
+    Arrange/SceneBuilder.hpp
+    Arrange/SceneBuilder.cpp
+    Arrange/Tasks/ArrangeTask.hpp
+    Arrange/Tasks/ArrangeTaskImpl.hpp
+    Arrange/Tasks/FillBedTask.hpp
+    Arrange/Tasks/FillBedTaskImpl.hpp
+    Arrange/Tasks/MultiplySelectionTask.hpp
+    Arrange/Tasks/MultiplySelectionTaskImpl.hpp
+    Arrange/SegmentedRectangleBed.hpp
+    Arrange/Core/ArrangeItemTraits.hpp
+    Arrange/Core/DataStoreTraits.hpp
+    Arrange/Core/ArrangeBase.hpp
+    Arrange/Core/PackingContext.hpp
+    Arrange/Core/ArrangeFirstFit.hpp
+    Arrange/Core/Beds.hpp
+    Arrange/Core/Beds.cpp
+    Arrange/Core/NFP/NFP.hpp
+    Arrange/Core/NFP/NFP.cpp
+    Arrange/Core/NFP/NFPConcave_CGAL.hpp
+    Arrange/Core/NFP/NFPConcave_CGAL.cpp
+    Arrange/Core/NFP/NFPConcave_Tesselate.hpp
+    Arrange/Core/NFP/NFPConcave_Tesselate.cpp
+    Arrange/Core/NFP/EdgeCache.hpp
+    Arrange/Core/NFP/EdgeCache.cpp
+    Arrange/Core/NFP/CircularEdgeIterator.hpp
+    Arrange/Core/NFP/NFPArrangeItemTraits.hpp
+    Arrange/Core/NFP/PackStrategyNFP.hpp
+    Arrange/Core/NFP/RectangleOverfitPackingStrategy.hpp
+    Arrange/Core/NFP/Kernels/KernelTraits.hpp
+    Arrange/Core/NFP/Kernels/GravityKernel.hpp
+    Arrange/Core/NFP/Kernels/TMArrangeKernel.hpp
+    Arrange/Core/NFP/Kernels/CompactifyKernel.hpp
+    Arrange/Core/NFP/Kernels/RectangleOverfitKernelWrapper.hpp
+    Arrange/Core/NFP/Kernels/SVGDebugOutputKernelWrapper.hpp
+    Arrange/Core/NFP/Kernels/KernelUtils.hpp
     MultiPoint.cpp
     MultiPoint.hpp
     MutablePriorityQueue.hpp
@@ -433,6 +482,10 @@ set(SLIC3R_SOURCES
 
 add_library(libslic3r STATIC ${SLIC3R_SOURCES})
 
+if (WIN32)
+    target_compile_definitions(libslic3r PUBLIC NOMINMAX)
+endif()
+
 foreach(_source IN ITEMS ${SLIC3R_SOURCES})
     get_filename_component(_source_path "${_source}" PATH)
     string(REPLACE "/" "\\" _group_path "${_source_path}")

src/libslic3r/ClipperUtils.cpp

@@ -773,8 +773,16 @@ Slic3r::ExPolygons intersection_ex(const Slic3r::SurfacesPtr &subject, const Sli
 // May be used to "heal" unusual models (3DLabPrints etc.) by providing fill_type (pftEvenOdd, pftNonZero, pftPositive, pftNegative).
 Slic3r::ExPolygons union_ex(const Slic3r::Polygons &subject, ClipperLib::PolyFillType fill_type)
     { return _clipper_ex(ClipperLib::ctUnion, ClipperUtils::PolygonsProvider(subject), ClipperUtils::EmptyPathsProvider(), ApplySafetyOffset::No, fill_type); }
+Slic3r::ExPolygons union_ex(const Slic3r::Polygons &subject, const Slic3r::Polygons &subject2, ClipperLib::PolyFillType fill_type)
+    { return _clipper_ex(ClipperLib::ctUnion, ClipperUtils::PolygonsProvider(subject), ClipperUtils::PolygonsProvider(subject2), ApplySafetyOffset::No, fill_type); }
 Slic3r::ExPolygons union_ex(const Slic3r::ExPolygons &subject)
     { return PolyTreeToExPolygons(clipper_do_polytree(ClipperLib::ctUnion, ClipperUtils::ExPolygonsProvider(subject), ClipperUtils::EmptyPathsProvider(), ClipperLib::pftNonZero)); }
+Slic3r::ExPolygons union_ex(const Slic3r::ExPolygons &subject, const Slic3r::ExPolygons &subject2)
+    { return PolyTreeToExPolygons(clipper_do_polytree(ClipperLib::ctUnion, ClipperUtils::ExPolygonsProvider(subject), ClipperUtils::ExPolygonsProvider(subject2), ClipperLib::pftNonZero)); }
+Slic3r::ExPolygons union_ex(const Slic3r::Polygons &subject, const Slic3r::ExPolygons &subject2)
+    { return PolyTreeToExPolygons(clipper_do_polytree(ClipperLib::ctUnion, ClipperUtils::PolygonsProvider(subject), ClipperUtils::ExPolygonsProvider(subject2), ClipperLib::pftNonZero)); }
+Slic3r::ExPolygons union_ex(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &subject2)
+    { return PolyTreeToExPolygons(clipper_do_polytree(ClipperLib::ctUnion, ClipperUtils::ExPolygonsProvider(subject), ClipperUtils::PolygonsProvider(subject2), ClipperLib::pftNonZero)); }
 Slic3r::ExPolygons union_ex(const Slic3r::Surfaces &subject)
     { return PolyTreeToExPolygons(clipper_do_polytree(ClipperLib::ctUnion, ClipperUtils::SurfacesProvider(subject), ClipperUtils::EmptyPathsProvider(), ClipperLib::pftNonZero)); }
 

src/libslic3r/ClipperUtils.hpp

@@ -498,7 +498,11 @@ Slic3r::Polygons union_(const Slic3r::Polygons &subject, const Slic3r::Polygons
 Slic3r::Polygons union_(const Slic3r::Polygons &subject, const Slic3r::ExPolygon &subject2);
 // May be used to "heal" unusual models (3DLabPrints etc.) by providing fill_type (pftEvenOdd, pftNonZero, pftPositive, pftNegative).
 Slic3r::ExPolygons union_ex(const Slic3r::Polygons &subject, ClipperLib::PolyFillType fill_type = ClipperLib::pftNonZero);
+Slic3r::ExPolygons union_ex(const Slic3r::Polygons &subject, const Slic3r::Polygons &subject2, ClipperLib::PolyFillType fill_type = ClipperLib::pftNonZero);
 Slic3r::ExPolygons union_ex(const Slic3r::ExPolygons &subject);
+Slic3r::ExPolygons union_ex(const Slic3r::ExPolygons &subject, const Slic3r::ExPolygons &subject2);
+Slic3r::ExPolygons union_ex(const Slic3r::ExPolygons &subject, const Slic3r::Polygons &subject2);
+Slic3r::ExPolygons union_ex(const Slic3r::Polygons &subject, const Slic3r::ExPolygons &subject2);
 Slic3r::ExPolygons union_ex(const Slic3r::Surfaces &subject);
 
 // Convert polygons / expolygons into ClipperLib::PolyTree using ClipperLib::pftEvenOdd, thus union will NOT be performed.

src/libslic3r/Config.cpp

@@ -797,6 +797,9 @@ ConfigSubstitutions ConfigBase::load(const boost::property_tree::ptree &tree, Fo
             // ignore
         }
     }
+    // Do legacy conversion on a completely loaded dictionary.
+    // Perform composite conversions, for example merging multiple keys into one key.
+    this->handle_legacy_composite();
     return std::move(substitutions_ctxt.substitutions);
 }
 

src/libslic3r/Config.hpp

@@ -2160,6 +2160,10 @@ protected:
     // If the opt_key is no more valid in this version of Slic3r, opt_key is cleared by handle_legacy().
     // handle_legacy() is called internally by set_deserialize().
     virtual void                    handle_legacy(t_config_option_key &/*opt_key*/, std::string &/*value*/) const {}
+    // Called after a config is loaded as a whole.
+    // Perform composite conversions, for example merging multiple keys into one key.
+    // For conversion of single options, the handle_legacy() method above is called.
+    virtual void                    handle_legacy_composite() {}
 
 public:
 	using ConfigOptionResolver::option;

src/libslic3r/CutUtils.cpp

@@ -0,0 +1,645 @@
+
+#include "CutUtils.hpp"
+#include "Geometry.hpp"
+#include "libslic3r.h"
+#include "Model.hpp"
+#include "TriangleMeshSlicer.hpp"
+#include "TriangleSelector.hpp"
+#include "ObjectID.hpp"
+
+
+namespace Slic3r {
+
+using namespace Geometry;
+
+static void apply_tolerance(ModelVolume* vol)
+{
+    ModelVolume::CutInfo& cut_info = vol->cut_info;
+
+    assert(cut_info.is_connector);
+    if (!cut_info.is_processed)
+        return;
+
+    Vec3d sf = vol->get_scaling_factor();
+
+    // make a "hole" wider
+    sf[X] += double(cut_info.radius_tolerance);
+    sf[Y] += double(cut_info.radius_tolerance);
+
+    // make a "hole" dipper
+    sf[Z] += double(cut_info.height_tolerance);
+
+    vol->set_scaling_factor(sf);
+
+    // correct offset in respect to the new depth
+    Vec3d rot_norm = rotation_transform(vol->get_rotation()) * Vec3d::UnitZ();
+    if (rot_norm.norm() != 0.0)
+        rot_norm.normalize();
+
+    double z_offset = 0.5 * static_cast<double>(cut_info.height_tolerance);
+    if (cut_info.connector_type == CutConnectorType::Plug || 
+        cut_info.connector_type == CutConnectorType::Snap)
+        z_offset -= 0.05; // add small Z offset to better preview
+
+    vol->set_offset(vol->get_offset() + rot_norm * z_offset);
+}
+
+static void add_cut_volume(TriangleMesh& mesh, ModelObject* object, const ModelVolume* src_volume, const Transform3d& cut_matrix, const std::string& suffix = {}, ModelVolumeType type = ModelVolumeType::MODEL_PART)
+{
+    if (mesh.empty())
+        return;
+
+    mesh.transform(cut_matrix);
+    ModelVolume* vol = object->add_volume(mesh);
+    vol->set_type(type);
+
+    vol->name = src_volume->name + suffix;
+    // Don't copy the config's ID.
+    vol->config.assign_config(src_volume->config);
+    assert(vol->config.id().valid());
+    assert(vol->config.id() != src_volume->config.id());
+    vol->set_material(src_volume->material_id(), *src_volume->material());
+    vol->cut_info = src_volume->cut_info;
+}
+
+static void process_volume_cut( ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,
+                                ModelObjectCutAttributes attributes, TriangleMesh& upper_mesh, TriangleMesh& lower_mesh)
+{
+    const auto volume_matrix = volume->get_matrix();
+
+    const Transformation cut_transformation = Transformation(cut_matrix);
+    const Transform3d invert_cut_matrix = cut_transformation.get_rotation_matrix().inverse() * translation_transform(-1 * cut_transformation.get_offset());
+
+    // Transform the mesh by the combined transformation matrix.
+    // Flip the triangles in case the composite transformation is left handed.
+    TriangleMesh mesh(volume->mesh());
+    mesh.transform(invert_cut_matrix * instance_matrix * volume_matrix, true);
+
+    indexed_triangle_set upper_its, lower_its;
+    cut_mesh(mesh.its, 0.0f, &upper_its, &lower_its);
+    if (attributes.has(ModelObjectCutAttribute::KeepUpper))
+        upper_mesh = TriangleMesh(upper_its);
+    if (attributes.has(ModelObjectCutAttribute::KeepLower))
+        lower_mesh = TriangleMesh(lower_its);
+}
+
+static void process_connector_cut(  ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,
+                                    ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower,
+                                    std::vector<ModelObject*>& dowels)
+{
+    assert(volume->cut_info.is_connector);
+    volume->cut_info.set_processed();
+
+    const auto volume_matrix = volume->get_matrix();
+
+    // ! Don't apply instance transformation for the conntectors.
+    // This transformation is already there
+    if (volume->cut_info.connector_type != CutConnectorType::Dowel) {
+        if (attributes.has(ModelObjectCutAttribute::KeepUpper)) {
+            ModelVolume* vol = nullptr;
+            if (volume->cut_info.connector_type == CutConnectorType::Snap) {
+                TriangleMesh mesh = TriangleMesh(its_make_cylinder(1.0, 1.0, PI / 180.));
+
+                vol = upper->add_volume(std::move(mesh));
+                vol->set_transformation(volume->get_transformation());
+                vol->set_type(ModelVolumeType::NEGATIVE_VOLUME);
+
+                vol->cut_info = volume->cut_info;
+                vol->name = volume->name;
+            }
+            else
+                vol = upper->add_volume(*volume);
+
+            vol->set_transformation(volume_matrix);
+            apply_tolerance(vol);
+        }
+        if (attributes.has(ModelObjectCutAttribute::KeepLower)) {
+            ModelVolume* vol = lower->add_volume(*volume);
+            vol->set_transformation(volume_matrix);
+            // for lower part change type of connector from NEGATIVE_VOLUME to MODEL_PART if this connector is a plug
+            vol->set_type(ModelVolumeType::MODEL_PART);
+        }
+    }
+    else {
+        if (attributes.has(ModelObjectCutAttribute::CreateDowels)) {
+            ModelObject* dowel{ nullptr };
+            // Clone the object to duplicate instances, materials etc.
+            volume->get_object()->clone_for_cut(&dowel);
+
+            // add one more solid part same as connector if this connector is a dowel
+            ModelVolume* vol = dowel->add_volume(*volume);
+            vol->set_type(ModelVolumeType::MODEL_PART);
+
+            // But discard rotation and Z-offset for this volume
+            vol->set_rotation(Vec3d::Zero());
+            vol->set_offset(Z, 0.0);
+
+            dowels.push_back(dowel);
+        }
+
+        // Cut the dowel
+        apply_tolerance(volume);
+
+        // Perform cut
+        TriangleMesh upper_mesh, lower_mesh;
+        process_volume_cut(volume, Transform3d::Identity(), cut_matrix, attributes, upper_mesh, lower_mesh);
+
+        // add small Z offset to better preview
+        upper_mesh.translate((-0.05 * Vec3d::UnitZ()).cast<float>());
+        lower_mesh.translate((0.05 * Vec3d::UnitZ()).cast<float>());
+
+        // Add cut parts to the related objects
+        add_cut_volume(upper_mesh, upper, volume, cut_matrix, "_A", volume->type());
+        add_cut_volume(lower_mesh, lower, volume, cut_matrix, "_B", volume->type());
+    }
+}
+
+static void process_modifier_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& inverse_cut_matrix,
+                                 ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower)
+{
+    const auto volume_matrix = instance_matrix * volume->get_matrix();
+
+    // Modifiers are not cut, but we still need to add the instance transformation
+    // to the modifier volume transformation to preserve their shape properly.
+    volume->set_transformation(Transformation(volume_matrix));
+
+    if (attributes.has(ModelObjectCutAttribute::KeepAsParts)) {
+        upper->add_volume(*volume);
+        return;
+    }
+
+    // Some logic for the negative volumes/connectors. Add only needed modifiers
+    auto bb = volume->mesh().transformed_bounding_box(inverse_cut_matrix * volume_matrix);
+    bool is_crossed_by_cut = bb.min[Z] <= 0 && bb.max[Z] >= 0;
+    if (attributes.has(ModelObjectCutAttribute::KeepUpper) && (bb.min[Z] >= 0 || is_crossed_by_cut))
+        upper->add_volume(*volume);
+    if (attributes.has(ModelObjectCutAttribute::KeepLower) && (bb.max[Z] <= 0 || is_crossed_by_cut))
+        lower->add_volume(*volume);
+}
+
+static void process_solid_part_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,
+                            ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower)
+{
+    // Perform cut
+    TriangleMesh upper_mesh, lower_mesh;
+    process_volume_cut(volume, instance_matrix, cut_matrix, attributes, upper_mesh, lower_mesh);
+
+    // Add required cut parts to the objects
+
+    if (attributes.has(ModelObjectCutAttribute::KeepAsParts)) {
+        add_cut_volume(upper_mesh, upper, volume, cut_matrix, "_A");
+        if (!lower_mesh.empty()) {
+            add_cut_volume(lower_mesh, upper, volume, cut_matrix, "_B");
+            upper->volumes.back()->cut_info.is_from_upper = false;
+        }
+        return;
+    }
+
+    if (attributes.has(ModelObjectCutAttribute::KeepUpper))
+        add_cut_volume(upper_mesh, upper, volume, cut_matrix);
+
+    if (attributes.has(ModelObjectCutAttribute::KeepLower) && !lower_mesh.empty())
+        add_cut_volume(lower_mesh, lower, volume, cut_matrix);
+}
+
+static void reset_instance_transformation(ModelObject* object, size_t src_instance_idx, 
+                                          const Transform3d& cut_matrix = Transform3d::Identity(),
+                                          bool place_on_cut = false, bool flip = false)
+{
+    // Reset instance transformation except offset and Z-rotation
+
+    for (size_t i = 0; i < object->instances.size(); ++i) {
+        auto& obj_instance = object->instances[i];
+        const double rot_z = obj_instance->get_rotation().z();
+        
+        Transformation inst_trafo = Transformation(obj_instance->get_transformation().get_matrix_no_scaling_factor());
+        // add respect to mirroring
+        if (obj_instance->is_left_handed())
+            inst_trafo = inst_trafo * Transformation(scale_transform(Vec3d(-1, 1, 1)));
+
+        obj_instance->set_transformation(inst_trafo);
+
+        Vec3d rotation = Vec3d::Zero();
+        if (!flip && !place_on_cut) {
+            if ( i != src_instance_idx)
+            rotation[Z] = rot_z;
+        }
+        else {
+            Transform3d rotation_matrix = Transform3d::Identity();
+            if (flip)
+                rotation_matrix = rotation_transform(PI * Vec3d::UnitX());
+
+            if (place_on_cut)
+                rotation_matrix = rotation_matrix * Transformation(cut_matrix).get_rotation_matrix().inverse();
+
+            if (i != src_instance_idx)
+                rotation_matrix = rotation_transform(rot_z * Vec3d::UnitZ()) * rotation_matrix;
+
+            rotation = Transformation(rotation_matrix).get_rotation();
+        }
+
+        obj_instance->set_rotation(rotation);
+    }
+}
+
+
+Cut::Cut(const ModelObject* object, int instance, const Transform3d& cut_matrix,
+         ModelObjectCutAttributes attributes/*= ModelObjectCutAttribute::KeepUpper | ModelObjectCutAttribute::KeepLower | ModelObjectCutAttribute::KeepAsParts*/)
+    : m_instance(instance), m_cut_matrix(cut_matrix), m_attributes(attributes)
+{
+    m_model = Model();
+    if (object)
+        m_model.add_object(*object);
+}
+
+void Cut::post_process(ModelObject* object, ModelObjectPtrs& cut_object_ptrs, bool keep, bool place_on_cut, bool flip)
+{
+    if (!object) return;
+
+    if (keep && !object->volumes.empty()) {
+        reset_instance_transformation(object, m_instance, m_cut_matrix, place_on_cut, flip);
+        cut_object_ptrs.push_back(object);
+    }
+    else
+        m_model.objects.push_back(object); // will be deleted in m_model.clear_objects();
+}
+
+void Cut::post_process(ModelObject* upper, ModelObject* lower, ModelObjectPtrs& cut_object_ptrs)
+{
+    post_process(upper, cut_object_ptrs,
+        m_attributes.has(ModelObjectCutAttribute::KeepUpper),
+        m_attributes.has(ModelObjectCutAttribute::PlaceOnCutUpper),
+        m_attributes.has(ModelObjectCutAttribute::FlipUpper));
+
+    post_process(lower, cut_object_ptrs,
+        m_attributes.has(ModelObjectCutAttribute::KeepLower),
+        m_attributes.has(ModelObjectCutAttribute::PlaceOnCutLower),
+        m_attributes.has(ModelObjectCutAttribute::PlaceOnCutLower) || m_attributes.has(ModelObjectCutAttribute::FlipLower));
+}
+
+
+void Cut::finalize(const ModelObjectPtrs& objects)
+{
+    //clear model from temporarry objects
+    m_model.clear_objects();
+
+    // add to model result objects
+    m_model.objects = objects;
+}
+
+
+const ModelObjectPtrs& Cut::perform_with_plane()
+{
+    if (!m_attributes.has(ModelObjectCutAttribute::KeepUpper) && !m_attributes.has(ModelObjectCutAttribute::KeepLower)) {
+        m_model.clear_objects();
+        return m_model.objects;
+    }
+
+    ModelObject* mo = m_model.objects.front();
+
+    BOOST_LOG_TRIVIAL(trace) << "ModelObject::cut - start";
+
+    // Clone the object to duplicate instances, materials etc.
+    ModelObject* upper{ nullptr };
+    if (m_attributes.has(ModelObjectCutAttribute::KeepUpper))
+        mo->clone_for_cut(&upper);
+
+    ModelObject* lower{ nullptr };
+    if (m_attributes.has(ModelObjectCutAttribute::KeepLower) && !m_attributes.has(ModelObjectCutAttribute::KeepAsParts))
+        mo->clone_for_cut(&lower);
+
+    std::vector<ModelObject*> dowels;
+
+    // Because transformations are going to be applied to meshes directly,
+    // we reset transformation of all instances and volumes,
+    // except for translation and Z-rotation on instances, which are preserved
+    // in the transformation matrix and not applied to the mesh transform.
+
+    const auto              instance_matrix = mo->instances[m_instance]->get_transformation().get_matrix_no_offset();
+    const Transformation    cut_transformation = Transformation(m_cut_matrix);
+    const Transform3d       inverse_cut_matrix = cut_transformation.get_rotation_matrix().inverse() * translation_transform(-1. * cut_transformation.get_offset());
+
+    for (ModelVolume* volume : mo->volumes) {
+        volume->reset_extra_facets();
+
+        if (!volume->is_model_part()) {
+            if (volume->cut_info.is_processed)
+                process_modifier_cut(volume, instance_matrix, inverse_cut_matrix, m_attributes, upper, lower);
+            else
+                process_connector_cut(volume, instance_matrix, m_cut_matrix, m_attributes, upper, lower, dowels);
+        }
+        else if (!volume->mesh().empty())
+            process_solid_part_cut(volume, instance_matrix, m_cut_matrix, m_attributes, upper, lower);
+    }
+
+    // Post-process cut parts
+
+    if (m_attributes.has(ModelObjectCutAttribute::KeepAsParts) && upper->volumes.empty()) {
+        m_model = Model();
+        m_model.objects.push_back(upper);
+        return m_model.objects;
+    }
+
+    ModelObjectPtrs cut_object_ptrs;
+
+    if (m_attributes.has(ModelObjectCutAttribute::KeepAsParts) && !upper->volumes.empty()) {
+        reset_instance_transformation(upper, m_instance, m_cut_matrix);
+        cut_object_ptrs.push_back(upper);
+    }
+    else {
+        // Delete all modifiers which are not intersecting with solid parts bounding box
+        auto delete_extra_modifiers = [this](ModelObject* mo) {
+            if (!mo) return;
+            const BoundingBoxf3 obj_bb = mo->instance_bounding_box(m_instance);
+            const Transform3d inst_matrix = mo->instances[m_instance]->get_transformation().get_matrix();
+
+            for (int i = int(mo->volumes.size()) - 1; i >= 0; --i)
+                if (const ModelVolume* vol = mo->volumes[i];
+                    !vol->is_model_part() && !vol->is_cut_connector()) {
+                    auto bb = vol->mesh().transformed_bounding_box(inst_matrix * vol->get_matrix());
+                    if (!obj_bb.intersects(bb))
+                        mo->delete_volume(i);
+                }
+        };
+
+        post_process(upper, lower, cut_object_ptrs);
+        delete_extra_modifiers(upper);
+        delete_extra_modifiers(lower);
+
+        if (m_attributes.has(ModelObjectCutAttribute::CreateDowels) && !dowels.empty()) {
+            for (auto dowel : dowels) {
+                reset_instance_transformation(dowel, m_instance);
+                dowel->name += "-Dowel-" + dowel->volumes[0]->name;
+                cut_object_ptrs.push_back(dowel);
+            }
+        }
+    }
+
+    BOOST_LOG_TRIVIAL(trace) << "ModelObject::cut - end";
+
+    finalize(cut_object_ptrs);
+
+    return m_model.objects;
+}
+
+static void distribute_modifiers_from_object(ModelObject* from_obj, const int instance_idx, ModelObject* to_obj1, ModelObject* to_obj2)
+{
+    auto              obj1_bb = to_obj1 ? to_obj1->instance_bounding_box(instance_idx) : BoundingBoxf3();
+    auto              obj2_bb = to_obj2 ? to_obj2->instance_bounding_box(instance_idx) : BoundingBoxf3();
+    const Transform3d inst_matrix = from_obj->instances[instance_idx]->get_transformation().get_matrix();
+
+    for (ModelVolume* vol : from_obj->volumes)
+        if (!vol->is_model_part()) {
+            auto bb = vol->mesh().transformed_bounding_box(inst_matrix * vol->get_matrix());
+            // Don't add modifiers which are not intersecting with solid parts
+            if (obj1_bb.intersects(bb))
+                to_obj1->add_volume(*vol);
+            if (obj2_bb.intersects(bb))
+                to_obj2->add_volume(*vol);
+        }
+}
+
+static void merge_solid_parts_inside_object(ModelObjectPtrs& objects)
+{
+    for (ModelObject* mo : objects) {
+        TriangleMesh mesh;
+        // Merge all SolidPart but not Connectors
+        for (const ModelVolume* mv : mo->volumes) {
+            if (mv->is_model_part() && !mv->is_cut_connector()) {
+                TriangleMesh m = mv->mesh();
+                m.transform(mv->get_matrix());
+                mesh.merge(m);
+            }
+        }
+        if (!mesh.empty()) {
+            ModelVolume* new_volume = mo->add_volume(mesh);
+            new_volume->name = mo->name;
+            // Delete all merged SolidPart but not Connectors
+            for (int i = int(mo->volumes.size()) - 2; i >= 0; --i) {
+                const ModelVolume* mv = mo->volumes[i];
+                if (mv->is_model_part() && !mv->is_cut_connector())
+                    mo->delete_volume(i);
+            }
+        }
+    }
+}
+
+
+const ModelObjectPtrs& Cut::perform_by_contour(std::vector<Part> parts, int dowels_count)
+{
+    ModelObject* cut_mo = m_model.objects.front();
+
+    // Clone the object to duplicate instances, materials etc.
+    ModelObject* upper{ nullptr };
+    if (m_attributes.has(ModelObjectCutAttribute::KeepUpper)) cut_mo->clone_for_cut(&upper);
+    ModelObject* lower{ nullptr };
+    if (m_attributes.has(ModelObjectCutAttribute::KeepLower)) cut_mo->clone_for_cut(&lower);
+
+    const size_t cut_parts_cnt = parts.size();
+    bool has_modifiers = false;
+
+    // Distribute SolidParts to the Upper/Lower object
+    for (size_t id = 0; id < cut_parts_cnt; ++id) {
+        if (parts[id].is_modifier)
+            has_modifiers = true; // modifiers will be added later to the related parts
+        else if (ModelObject* obj = (parts[id].selected ? upper : lower))
+            obj->add_volume(*(cut_mo->volumes[id]));
+    }
+
+    if (has_modifiers) {
+        // Distribute Modifiers to the Upper/Lower object
+        distribute_modifiers_from_object(cut_mo, m_instance, upper, lower);
+    }
+
+    ModelObjectPtrs cut_object_ptrs;
+
+    ModelVolumePtrs& volumes = cut_mo->volumes;
+    if (volumes.size() == cut_parts_cnt) {
+        // Means that object is cut without connectors
+
+        // Just add Upper and Lower objects to cut_object_ptrs
+        post_process(upper, lower, cut_object_ptrs);
+    }
+    else if (volumes.size() > cut_parts_cnt) {
+        // Means that object is cut with connectors
+
+        // All volumes are distributed to Upper / Lower object,
+        // So we don’t need them anymore
+        for (size_t id = 0; id < cut_parts_cnt; id++)
+            delete* (volumes.begin() + id);
+        volumes.erase(volumes.begin(), volumes.begin() + cut_parts_cnt);
+
+        // Perform cut just to get connectors
+        Cut cut(cut_mo, m_instance, m_cut_matrix, m_attributes);
+        const ModelObjectPtrs& cut_connectors_obj = cut.perform_with_plane();
+        assert(dowels_count > 0 ? cut_connectors_obj.size() >= 3 : cut_connectors_obj.size() == 2);
+
+        // Connectors from upper object
+        for (const ModelVolume* volume : cut_connectors_obj[0]->volumes)
+            upper->add_volume(*volume, volume->type());
+
+        // Connectors from lower object
+        for (const ModelVolume* volume : cut_connectors_obj[1]->volumes)
+            lower->add_volume(*volume, volume->type());
+
+        // Add Upper and Lower objects to cut_object_ptrs
+        post_process(upper, lower, cut_object_ptrs);
+
+        // Add Dowel-connectors as separate objects to cut_object_ptrs
+        if (cut_connectors_obj.size() >= 3)
+            for (size_t id = 2; id < cut_connectors_obj.size(); id++)
+                cut_object_ptrs.push_back(cut_connectors_obj[id]);
+    }
+
+    // Now merge all model parts together:
+    merge_solid_parts_inside_object(cut_object_ptrs);
+
+    finalize(cut_object_ptrs);
+
+    return m_model.objects;
+}
+
+
+const ModelObjectPtrs& Cut::perform_with_groove(const Groove& groove, const Transform3d& rotation_m, bool keep_as_parts/* = false*/)
+{
+    ModelObject* cut_mo = m_model.objects.front();
+
+    // Clone the object to duplicate instances, materials etc.
+    ModelObject* upper{ nullptr };
+    cut_mo->clone_for_cut(&upper);
+    ModelObject* lower{ nullptr };
+    cut_mo->clone_for_cut(&lower);
+
+    const double groove_half_depth = 0.5 * double(groove.depth);
+
+    Model tmp_model_for_cut = Model();
+
+    Model tmp_model = Model();
+    tmp_model.add_object(*cut_mo);
+    ModelObject* tmp_object = tmp_model.objects.front();
+
+    auto add_volumes_from_cut = [](ModelObject* object, const ModelObjectCutAttribute attribute, const Model& tmp_model_for_cut) {
+        const auto& volumes = tmp_model_for_cut.objects.front()->volumes;
+        for (const ModelVolume* volume : volumes)
+            if (volume->is_model_part()) {
+                if ((attribute == ModelObjectCutAttribute::KeepUpper && volume->is_from_upper()) ||
+                    (attribute != ModelObjectCutAttribute::KeepUpper && !volume->is_from_upper())) {
+                    ModelVolume* new_vol = object->add_volume(*volume);
+                    new_vol->reset_from_upper();
+                }
+            }
+    };
+
+    auto cut = [this, add_volumes_from_cut]
+                (ModelObject* object, const Transform3d& cut_matrix, const ModelObjectCutAttribute add_volumes_attribute, Model& tmp_model_for_cut) {
+        Cut cut(object, m_instance, cut_matrix);
+
+        tmp_model_for_cut = Model();
+        tmp_model_for_cut.add_object(*cut.perform_with_plane().front());
+        assert(!tmp_model_for_cut.objects.empty());
+
+        object->clear_volumes();
+        add_volumes_from_cut(object, add_volumes_attribute, tmp_model_for_cut);
+        reset_instance_transformation(object, m_instance);
+    };
+
+    // cut by upper plane
+
+    const Transform3d cut_matrix_upper = translation_transform(rotation_m * (groove_half_depth * Vec3d::UnitZ())) * m_cut_matrix;
+    {
+        cut(tmp_object, cut_matrix_upper, ModelObjectCutAttribute::KeepLower, tmp_model_for_cut);
+        add_volumes_from_cut(upper, ModelObjectCutAttribute::KeepUpper, tmp_model_for_cut);
+    }
+
+    // cut by lower plane
+
+    const Transform3d cut_matrix_lower = translation_transform(rotation_m * (-groove_half_depth * Vec3d::UnitZ())) * m_cut_matrix;
+    {
+        cut(tmp_object, cut_matrix_lower, ModelObjectCutAttribute::KeepUpper, tmp_model_for_cut);
+        add_volumes_from_cut(lower, ModelObjectCutAttribute::KeepLower, tmp_model_for_cut);
+    }
+
+    // cut middle part with 2 angles and add parts to related upper/lower objects
+
+    const double h_side_shift = 0.5 * double(groove.width + groove.depth / tan(groove.flaps_angle));
+
+    // cut by angle1 plane
+    {
+        const Transform3d cut_matrix_angle1 = translation_transform(rotation_m * (-h_side_shift * Vec3d::UnitX())) * m_cut_matrix * rotation_transform(Vec3d(0, -groove.flaps_angle, -groove.angle));
+
+        cut(tmp_object, cut_matrix_angle1, ModelObjectCutAttribute::KeepLower, tmp_model_for_cut);
+        add_volumes_from_cut(lower, ModelObjectCutAttribute::KeepUpper, tmp_model_for_cut);
+    }
+
+    // cut by angle2 plane
+    {
+        const Transform3d cut_matrix_angle2 = translation_transform(rotation_m * (h_side_shift * Vec3d::UnitX())) * m_cut_matrix * rotation_transform(Vec3d(0, groove.flaps_angle, groove.angle));
+
+        cut(tmp_object, cut_matrix_angle2, ModelObjectCutAttribute::KeepLower, tmp_model_for_cut);
+        add_volumes_from_cut(lower, ModelObjectCutAttribute::KeepUpper, tmp_model_for_cut);
+    }
+
+    // apply tolerance to the middle part
+    {
+        const double h_groove_shift_tolerance = groove_half_depth - (double)groove.depth_tolerance;
+
+        const Transform3d cut_matrix_lower_tolerance = translation_transform(rotation_m * (-h_groove_shift_tolerance * Vec3d::UnitZ())) * m_cut_matrix;
+        cut(tmp_object, cut_matrix_lower_tolerance, ModelObjectCutAttribute::KeepUpper, tmp_model_for_cut);
+
+        const double h_side_shift_tolerance = h_side_shift - 0.5 * double(groove.width_tolerance);
+
+        const Transform3d cut_matrix_angle1_tolerance = translation_transform(rotation_m * (-h_side_shift_tolerance * Vec3d::UnitX())) * m_cut_matrix * rotation_transform(Vec3d(0, -groove.flaps_angle, -groove.angle));
+        cut(tmp_object, cut_matrix_angle1_tolerance, ModelObjectCutAttribute::KeepLower, tmp_model_for_cut);
+
+        const Transform3d cut_matrix_angle2_tolerance = translation_transform(rotation_m * (h_side_shift_tolerance * Vec3d::UnitX())) * m_cut_matrix * rotation_transform(Vec3d(0, groove.flaps_angle, groove.angle));
+        cut(tmp_object, cut_matrix_angle2_tolerance, ModelObjectCutAttribute::KeepUpper, tmp_model_for_cut);
+    }
+
+    // this part can be added to the upper object now
+    add_volumes_from_cut(upper, ModelObjectCutAttribute::KeepLower, tmp_model_for_cut);
+
+    ModelObjectPtrs cut_object_ptrs;
+
+    if (keep_as_parts) {
+        // add volumes from lower object to the upper, but mark them as a lower
+        const auto& volumes = lower->volumes;
+        for (const ModelVolume* volume : volumes) {
+            ModelVolume* new_vol = upper->add_volume(*volume);
+            new_vol->cut_info.is_from_upper = false;
+        }
+
+        // add modifiers
+        for (const ModelVolume* volume : cut_mo->volumes)
+            if (!volume->is_model_part())
+                upper->add_volume(*volume);
+
+        cut_object_ptrs.push_back(upper);
+
+        // add lower object to the cut_object_ptrs just to correct delete it from the Model destructor and avoid memory leaks
+        cut_object_ptrs.push_back(lower);
+    }
+    else {
+        // add modifiers if object has any
+        for (const ModelVolume* volume : cut_mo->volumes)
+            if (!volume->is_model_part()) {
+                distribute_modifiers_from_object(cut_mo, m_instance, upper, lower);
+                break;
+            }
+
+        assert(!upper->volumes.empty() && !lower->volumes.empty());
+
+        // Add Upper and Lower parts to cut_object_ptrs
+
+        post_process(upper, lower, cut_object_ptrs);
+
+        // Now merge all model parts together:
+        merge_solid_parts_inside_object(cut_object_ptrs);
+    }
+
+    finalize(cut_object_ptrs);
+
+    return m_model.objects;
+}
+
+} // namespace Slic3r
+

src/libslic3r/CutUtils.hpp

@@ -0,0 +1,66 @@
+#ifndef slic3r_CutUtils_hpp_
+#define slic3r_CutUtils_hpp_
+
+#include "enum_bitmask.hpp"
+#include "Point.hpp"
+#include "Model.hpp"
+
+#include <vector>
+
+namespace Slic3r {
+
+using ModelObjectPtrs = std::vector<ModelObject*>;
+
+enum class ModelObjectCutAttribute : int { KeepUpper, KeepLower, KeepAsParts, FlipUpper, FlipLower, PlaceOnCutUpper, PlaceOnCutLower, CreateDowels, InvalidateCutInfo };
+using ModelObjectCutAttributes = enum_bitmask<ModelObjectCutAttribute>;
+ENABLE_ENUM_BITMASK_OPERATORS(ModelObjectCutAttribute);
+
+
+class Cut {
+
+    Model                       m_model;
+    int                         m_instance;
+    const Transform3d           m_cut_matrix;
+    ModelObjectCutAttributes    m_attributes;
+
+    void post_process(ModelObject* object, ModelObjectPtrs& objects, bool keep, bool place_on_cut, bool flip);
+    void post_process(ModelObject* upper_object, ModelObject* lower_object, ModelObjectPtrs& objects);
+    void finalize(const ModelObjectPtrs& objects);
+
+public:
+
+    Cut(const ModelObject* object, int instance, const Transform3d& cut_matrix, 
+        ModelObjectCutAttributes attributes = ModelObjectCutAttribute::KeepUpper |
+                                              ModelObjectCutAttribute::KeepLower |
+                                              ModelObjectCutAttribute::KeepAsParts );
+    ~Cut() { m_model.clear_objects(); }
+
+    struct Groove
+    {
+        float depth{ 0.f };
+        float width{ 0.f };
+        float flaps_angle{ 0.f };
+        float angle{ 0.f };
+        float depth_init{ 0.f };
+        float width_init{ 0.f };
+        float flaps_angle_init{ 0.f };
+        float angle_init{ 0.f };
+        float depth_tolerance{ 0.1f };
+        float width_tolerance{ 0.1f };
+    };
+
+    struct Part
+    {
+        bool selected;
+        bool is_modifier;
+    };
+
+    const ModelObjectPtrs& perform_with_plane();
+    const ModelObjectPtrs& perform_by_contour(std::vector<Part> parts, int dowels_count);
+    const ModelObjectPtrs& perform_with_groove(const Groove& groove, const Transform3d& rotation_m, bool keep_as_parts = false);
+
+}; // namespace Cut
+
+} // namespace Slic3r
+
+#endif /* slic3r_CutUtils_hpp_ */

src/libslic3r/GCode.cpp

@@ -239,9 +239,12 @@ namespace Slic3r {
 
         const bool needs_toolchange = gcodegen.writer().need_toolchange(new_extruder_id);
         const bool will_go_down = ! is_approx(z, current_z);
-        if (tcr.force_travel || ! needs_toolchange || (gcodegen.config().single_extruder_multi_material && ! tcr.priming)) {
-            // Move over the wipe tower. If this is not single-extruder MM, the first wipe tower move following the
-            // toolchange will travel there anyway (if there is a toolchange).
+        const bool is_ramming = (gcodegen.config().single_extruder_multi_material && ! tcr.priming)
+                             || (! gcodegen.config().single_extruder_multi_material && gcodegen.config().filament_multitool_ramming.get_at(tcr.initial_tool));
+        const bool should_travel_to_tower = tcr.force_travel        // wipe tower says so
+                                         || ! needs_toolchange      // this is just finishing the tower with no toolchange
+                                         || is_ramming;
+        if (should_travel_to_tower) {
             // FIXME: It would be better if the wipe tower set the force_travel flag for all toolchanges,
             // then we could simplify the condition and make it more readable.
             gcode += gcodegen.retract();
@@ -251,6 +254,9 @@ namespace Slic3r {
                 ExtrusionRole::Mixed,
                 "Travel to a Wipe Tower");
             gcode += gcodegen.unretract();
+        } else {
+            // When this is multiextruder printer without any ramming, we can just change
+            // the tool without travelling to the tower.
         }
         
         if (will_go_down) {
@@ -262,7 +268,7 @@ namespace Slic3r {
         std::string toolchange_gcode_str;
         std::string deretraction_str;
         if (tcr.priming || (new_extruder_id >= 0 && needs_toolchange)) {
-            if (gcodegen.config().single_extruder_multi_material)
+            if (is_ramming)
                 gcodegen.m_wipe.reset_path(); // We don't want wiping on the ramming lines.
             toolchange_gcode_str = gcodegen.set_extruder(new_extruder_id, tcr.print_z); // TODO: toolchange_z vs print_z
             if (gcodegen.config().wipe_tower)

src/libslic3r/GCode/PostProcessor.cpp

@@ -16,7 +16,9 @@
 
 // The standard Windows includes.
 #define WIN32_LEAN_AND_MEAN
+#ifndef NOMINMAX
 #define NOMINMAX
+#endif
 #include <Windows.h>
 #include <shellapi.h>
 

src/libslic3r/GCode/WipeTower.cpp

@@ -559,6 +559,7 @@ WipeTower::WipeTower(const PrintConfig& config, const PrintRegionConfig& default
         m_extra_loading_move      = float(config.extra_loading_move);
         m_set_extruder_trimpot    = config.high_current_on_filament_swap;
     }
+
     // Calculate where the priming lines should be - very naive test not detecting parallelograms etc.
     const std::vector<Vec2d>& bed_points = config.bed_shape.values;
     BoundingBoxf bb(bed_points);
@@ -625,6 +626,24 @@ void WipeTower::set_extruder(size_t idx, const PrintConfig& config)
         m_filpar[idx].ramming_step_multiplicator /= 100;
         while (stream >> speed)
             m_filpar[idx].ramming_speed.push_back(speed);
+        // ramming_speed now contains speeds to be used for every 0.25s piece of the ramming line.
+        // This allows to have the ramming flow variable. The 0.25s value is how it is saved in config
+        // and the same time step has to be used when the ramming is performed.
+    } else {
+        // We will use the same variables internally, but the correspondence to the configuration options will be different.
+        float vol  = config.filament_multitool_ramming_volume.get_at(idx);
+        float flow = config.filament_multitool_ramming_flow.get_at(idx);
+        m_filpar[idx].multitool_ramming = config.filament_multitool_ramming.get_at(idx);
+        m_filpar[idx].ramming_line_width_multiplicator = 2.;
+        m_filpar[idx].ramming_step_multiplicator = 1.;
+
+        // Now the ramming speed vector. In this case it contains just one value (flow).
+        // The time is calculated and saved separately. This is here so that the MM ramming
+        // is not limited by the 0.25s granularity - it is not possible to create a SEMM-style
+        // ramming_speed vector that would respect both the volume and flow (because of 
+        // rounding issues with small volumes and high flow).
+        m_filpar[idx].ramming_speed.push_back(flow);
+        m_filpar[idx].multitool_ramming_time = vol/flow;
     }
 
     m_used_filament_length.resize(std::max(m_used_filament_length.size(), idx + 1)); // makes sure that the vector is big enough so we don't have to check later
@@ -839,12 +858,17 @@ void WipeTower::toolchange_Unload(
 	float remaining = xr - xl ;							// keeps track of distance to the next turnaround
 	float e_done = 0;									// measures E move done from each segment   
 
-    if (m_semm)
+    const bool do_ramming = m_semm || m_filpar[m_current_tool].multitool_ramming;
+
+    if (do_ramming) {
         writer.travel(ramming_start_pos); // move to starting position
+        writer.disable_linear_advance();
+    }
     else
         writer.set_position(ramming_start_pos);
+
     // if the ending point of the ram would end up in mid air, align it with the end of the wipe tower:
-    if (m_semm && (m_layer_info > m_plan.begin() && m_layer_info < m_plan.end() && (m_layer_info-1!=m_plan.begin() || !m_adhesion ))) {
+    if (do_ramming && (m_layer_info > m_plan.begin() && m_layer_info < m_plan.end() && (m_layer_info-1!=m_plan.begin() || !m_adhesion ))) {
 
         // this is y of the center of previous sparse infill border
         float sparse_beginning_y = 0.f;
@@ -872,16 +896,18 @@ void WipeTower::toolchange_Unload(
             sum_of_depths += tch.required_depth;
         }
     }
-
-    writer.disable_linear_advance();
+    
 
     // now the ramming itself:
-    while (m_semm && i < m_filpar[m_current_tool].ramming_speed.size())
+    while (do_ramming && i < m_filpar[m_current_tool].ramming_speed.size())
     {
-        const float x = volume_to_length(m_filpar[m_current_tool].ramming_speed[i] * 0.25f, line_width, m_layer_height);
-        const float e = m_filpar[m_current_tool].ramming_speed[i] * 0.25f / filament_area(); // transform volume per sec to E move;
-        const float dist = std::min(x - e_done, remaining);		  // distance to travel for either the next 0.25s, or to the next turnaround
-        const float actual_time = dist/x * 0.25f;
+        // The time step is different for SEMM ramming and the MM ramming. See comments in set_extruder() for details.
+        const float time_step = m_semm ? 0.25f : m_filpar[m_current_tool].multitool_ramming_time;
+
+        const float x = volume_to_length(m_filpar[m_current_tool].ramming_speed[i] * time_step, line_width, m_layer_height);
+        const float e = m_filpar[m_current_tool].ramming_speed[i] * time_step / filament_area(); // transform volume per sec to E move;
+        const float dist = std::min(x - e_done, remaining);		  // distance to travel for either the next time_step, or to the next turnaround
+        const float actual_time = dist/x * time_step;
         writer.ram(writer.x(), writer.x() + (m_left_to_right ? 1.f : -1.f) * dist, 0.f, 0.f, e * (dist / x), dist / (actual_time / 60.f));
         remaining -= dist;
 
@@ -953,7 +979,7 @@ void WipeTower::toolchange_Unload(
     // this is to align ramming and future wiping extrusions, so the future y-steps can be uniform from the start:
     // the perimeter_width will later be subtracted, it is there to not load while moving over just extruded material
     Vec2f pos = Vec2f(end_of_ramming.x(), end_of_ramming.y() + (y_step/m_extra_spacing-m_perimeter_width) / 2.f + m_perimeter_width);
-    if (m_semm)
+    if (do_ramming)
         writer.travel(pos, 2400.f);
     else
         writer.set_position(pos);
@@ -1040,8 +1066,9 @@ void WipeTower::toolchange_Wipe(
     //   the ordered volume, even if it means violating the box. This can later be removed and simply
     // wipe until the end of the assigned area.
 
-	float x_to_wipe = volume_to_length(wipe_volume, m_perimeter_width, m_layer_height);
-	float dy = m_extra_spacing*m_perimeter_width;
+	float x_to_wipe = volume_to_length(wipe_volume, m_perimeter_width, m_layer_height) * (is_first_layer() ? m_extra_spacing : 1.f);
+	float dy = (is_first_layer() ? 1.f : m_extra_spacing) * m_perimeter_width; // Don't use the extra spacing for the first layer.
+    // All the calculations in all other places take the spacing into account for all the layers.
 
     const float target_speed = is_first_layer() ? m_first_layer_speed * 60.f : m_infill_speed * 60.f;
     float wipe_speed = 0.33f * target_speed;

src/libslic3r/GCode/WipeTower.hpp

@@ -241,6 +241,8 @@ public:
         std::vector<float>  ramming_speed;
         float               nozzle_diameter;
         float               filament_area;
+		bool			    multitool_ramming;
+		float               multitool_ramming_time = 0.f;
     };
 
 private:

src/libslic3r/Geometry/ConvexHull.hpp

@@ -3,11 +3,10 @@
 
 #include <vector>
 
-#include "../Polygon.hpp"
+#include "../ExPolygon.hpp"
 
 namespace Slic3r {
 
-class ExPolygon;
 using ExPolygons = std::vector<ExPolygon>;
 
 namespace Geometry {
@@ -16,7 +15,9 @@ Pointf3s convex_hull(Pointf3s points);
 Polygon convex_hull(Points points);
 Polygon convex_hull(const Polygons &polygons);
 Polygon convex_hull(const ExPolygons &expolygons);
-Polygon convex_hulll(const Polylines &polylines);
+Polygon convex_hull(const Polylines &polylines);
+inline Polygon convex_hull(const Polygon &poly) { return convex_hull(poly.points); }
+inline Polygon convex_hull(const ExPolygon &poly) { return convex_hull(poly.contour.points); }
 
 // Returns true if the intersection of the two convex polygons A and B
 // is not an empty set.

src/libslic3r/Line.hpp

@@ -38,6 +38,32 @@ template<class L> using Scalar = typename Traits<remove_cvref_t<L>>::Scalar;
 template<class L> auto get_a(L &&l) { return Traits<remove_cvref_t<L>>::get_a(l); }
 template<class L> auto get_b(L &&l) { return Traits<remove_cvref_t<L>>::get_b(l); }
 
+template<class L> auto sqlength(L &&l)
+{
+    return (get_b(l) - get_a(l)).squaredNorm();
+}
+
+template<class Scalar, class L>
+auto sqlength(L &&l)
+{
+    return (get_b(l).template cast<Scalar>() - get_a(l).template cast<Scalar>()).squaredNorm();
+}
+
+template<class L, class = std::enable_if_t<Dim<L> == 2> >
+auto angle_to_x(const L &l)
+{
+    auto dx = double(get_b(l).x()) - get_a(l).x();
+    auto dy = double(get_b(l).y()) - get_a(l).y();
+
+    double a = std::atan2(dy, dx);
+    auto s   = std::signbit(a);
+
+    if(s)
+        a += 2. * PI;
+
+    return a;
+}
+
 // Distance to the closest point of line.
 template<class L>
 inline double distance_to_squared(const L &line, const Vec<Dim<L>, Scalar<L>> &point, Vec<Dim<L>, Scalar<L>> *nearest_point)
@@ -162,7 +188,7 @@ public:
     void   translate(double x, double y) { this->translate(Point(x, y)); }
     void   rotate(double angle, const Point &center) { this->a.rotate(angle, center); this->b.rotate(angle, center); }
     void   reverse() { std::swap(this->a, this->b); }
-    double length() const { return (b - a).cast<double>().norm(); }
+    double length() const { return (b.cast<double>() - a.cast<double>()).norm(); }
     Point  midpoint() const { return (this->a + this->b) / 2; }
     bool   intersection_infinite(const Line &other, Point* point) const;
     bool   operator==(const Line &rhs) const { return this->a == rhs.a && this->b == rhs.b; }

src/libslic3r/Measure.cpp

@@ -72,7 +72,7 @@ public:
     int get_num_of_planes() const;
     const std::vector<int>& get_plane_triangle_indices(int idx) const;
     const std::vector<SurfaceFeature>& get_plane_features(unsigned int plane_id);
-    const TriangleMesh& get_mesh() const;
+    const indexed_triangle_set& get_its() const;
 
 private:
     void update_planes();
@@ -80,7 +80,7 @@ private:
     
     std::vector<PlaneData> m_planes;
     std::vector<size_t>    m_face_to_plane;
-    TriangleMesh m_mesh;
+    indexed_triangle_set   m_its;
 };
 
 
@@ -89,7 +89,7 @@ private:
 
 
 MeasuringImpl::MeasuringImpl(const indexed_triangle_set& its)
-: m_mesh(its)
+: m_its(its)
 {
     update_planes();
 
@@ -104,14 +104,12 @@ MeasuringImpl::MeasuringImpl(const indexed_triangle_set& its)
 
 void MeasuringImpl::update_planes()
 {
-    m_planes.clear();
-
     // Now we'll go through all the facets and append Points of facets sharing the same normal.
     // This part is still performed in mesh coordinate system.
-    const size_t             num_of_facets = m_mesh.its.indices.size();
+    const size_t             num_of_facets = m_its.indices.size();
     m_face_to_plane.resize(num_of_facets, size_t(-1));
-    const std::vector<Vec3f> face_normals = its_face_normals(m_mesh.its);
-    const std::vector<Vec3i> face_neighbors = its_face_neighbors(m_mesh.its);
+    const std::vector<Vec3f> face_normals = its_face_normals(m_its);
+    const std::vector<Vec3i> face_neighbors = its_face_neighbors(m_its);
     std::vector<int>         facet_queue(num_of_facets, 0);
     int                      facet_queue_cnt = 0;
     const stl_normal*        normal_ptr      = nullptr;
@@ -121,6 +119,10 @@ void MeasuringImpl::update_planes()
         return (std::abs(a(0) - b(0)) < 0.001 && std::abs(a(1) - b(1)) < 0.001 && std::abs(a(2) - b(2)) < 0.001);
     };
 
+    m_planes.clear();
+    m_planes.reserve(num_of_facets / 5); // empty plane data object is quite lightweight, let's save the initial reallocations
+
+
     // First go through all the triangles and fill in m_planes vector. For each "plane"
     // detected on the model, it will contain list of facets that are part of it.
     // We will also fill in m_face_to_plane, which contains index into m_planes
@@ -132,7 +134,7 @@ void MeasuringImpl::update_planes()
                 facet_queue[facet_queue_cnt ++] = seed_facet_idx;
                 normal_ptr = &face_normals[seed_facet_idx];
                 m_face_to_plane[seed_facet_idx] = m_planes.size();
-                m_planes.emplace_back();                
+                m_planes.emplace_back();
                 break;
             }
         if (seed_facet_idx == num_of_facets)
@@ -160,16 +162,21 @@ void MeasuringImpl::update_planes()
     assert(std::none_of(m_face_to_plane.begin(), m_face_to_plane.end(), [](size_t val) { return val == size_t(-1); }));
 
     // Now we will walk around each of the planes and save vertices which form the border.
-    SurfaceMesh sm(m_mesh.its);
-    for (int plane_id=0; plane_id < int(m_planes.size()); ++plane_id) {
-        const auto& facets = m_planes[plane_id].facets;
-        m_planes[plane_id].borders.clear();
+    const SurfaceMesh sm(m_its);
+
+    const auto& face_to_plane = m_face_to_plane;
+    auto& planes = m_planes;
+
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, m_planes.size()),
+        [&planes, &face_to_plane, &face_neighbors, &sm](const tbb::blocked_range<size_t>& range) {
+            for (size_t plane_id = range.begin(); plane_id != range.end(); ++plane_id) {
+
+        const auto& facets = planes[plane_id].facets;
+        planes[plane_id].borders.clear();
         std::vector<std::array<bool, 3>> visited(facets.size(), {false, false, false});
         
-        
-
         for (int face_id=0; face_id<int(facets.size()); ++face_id) {
-            assert(m_face_to_plane[facets[face_id]] == plane_id);
+            assert(face_to_plane[facets[face_id]] == plane_id);
 
             for (int edge_id=0; edge_id<3; ++edge_id) {
                 // Every facet's edge which has a neighbor from a different plane is
@@ -177,7 +184,7 @@ void MeasuringImpl::update_planes()
                 int neighbor_idx = face_neighbors[facets[face_id]][edge_id];
                 if (neighbor_idx == -1)
                     goto PLANE_FAILURE;
-                if (visited[face_id][edge_id] || (int)m_face_to_plane[neighbor_idx] == plane_id) {
+                if (visited[face_id][edge_id] || (int)face_to_plane[neighbor_idx] == plane_id) {
                     visited[face_id][edge_id] = true;
                     continue;
                 }
@@ -188,8 +195,9 @@ void MeasuringImpl::update_planes()
             
                 // he is the first halfedge on the border. Now walk around and append the points.
                 //const Halfedge_index he_orig = he;
-                m_planes[plane_id].borders.emplace_back();
-                std::vector<Vec3d>& last_border = m_planes[plane_id].borders.back();
+                planes[plane_id].borders.emplace_back();
+                std::vector<Vec3d>& last_border = planes[plane_id].borders.back();
+                last_border.reserve(4);
                 last_border.emplace_back(sm.point(sm.source(he)).cast<double>());
                 //Vertex_index target = sm.target(he);
                 const Halfedge_index he_start = he;
@@ -210,7 +218,7 @@ void MeasuringImpl::update_planes()
                     // Remember all halfedges we saw to break out of such infinite loops.
                     boost::container::small_vector<Halfedge_index, 10> he_seen;
 
-                    while ( (int)m_face_to_plane[sm.face(he)] == plane_id && he != he_orig) {
+                    while ( (int)face_to_plane[sm.face(he)] == plane_id && he != he_orig) {
                         he_seen.emplace_back(he);
                         he = sm.next_around_target(he);
                         if (he.is_invalid() || std::find(he_seen.begin(), he_seen.end(), he) != he_seen.end())
@@ -241,7 +249,7 @@ void MeasuringImpl::update_planes()
                 } while (he != he_start);
 
                 if (last_border.size() == 1)
-                    m_planes[plane_id].borders.pop_back();
+                    planes[plane_id].borders.pop_back();
                 else {
                     assert(last_border.front() == last_border.back());
                     last_border.pop_back();
@@ -251,8 +259,9 @@ void MeasuringImpl::update_planes()
         continue; // There was no failure.
 
         PLANE_FAILURE:
-            m_planes[plane_id].borders.clear();
-    }
+            planes[plane_id].borders.clear();
+    }});
+    m_planes.shrink_to_fit();
 }
 
 
@@ -581,9 +590,9 @@ const std::vector<SurfaceFeature>& MeasuringImpl::get_plane_features(unsigned in
     return m_planes[plane_id].surface_features;
 }
 
-const TriangleMesh& MeasuringImpl::get_mesh() const
+const indexed_triangle_set& MeasuringImpl::get_its() const
 {
-    return this->m_mesh;
+    return this->m_its;
 }
 
 
@@ -626,9 +635,9 @@ const std::vector<SurfaceFeature>& Measuring::get_plane_features(unsigned int pl
     return priv->get_plane_features(plane_id);
 }
 
-const TriangleMesh& Measuring::get_mesh() const
+const indexed_triangle_set& Measuring::get_its() const
 {
-    return priv->get_mesh();
+    return priv->get_its();
 }
 
 const AngleAndEdges AngleAndEdges::Dummy = { 0.0, Vec3d::Zero(), { Vec3d::Zero(), Vec3d::Zero() }, { Vec3d::Zero(), Vec3d::Zero() }, 0.0, true };

src/libslic3r/Measure.hpp

@@ -109,7 +109,7 @@ public:
     const std::vector<SurfaceFeature>& get_plane_features(unsigned int plane_id) const;
 
     // Returns the mesh used for measuring
-    const TriangleMesh& get_mesh() const;
+    const indexed_triangle_set& get_its() const;
 
 private: 
     std::unique_ptr<MeasuringImpl> priv;

src/libslic3r/MinAreaBoundingBox.cpp

@@ -1,6 +1,7 @@
 #include "MinAreaBoundingBox.hpp"
 
 #include <libslic3r/ExPolygon.hpp>
+#include <BoundingBox.hpp>
 
 #if defined(_MSC_VER) && defined(__clang__)
 #define BOOST_NO_CXX17_HDR_STRING_VIEW
@@ -103,4 +104,16 @@ void remove_collinear_points(ExPolygon &p)
 {
     p = libnest2d::removeCollinearPoints<ExPolygon>(p, Unit(0));
 }
+
+double fit_into_box_rotation(const Polygon &shape, const BoundingBox &bb)
+{
+    using namespace libnest2d;
+
+    _Box<Point> box{{bb.min.x(), bb.min.y()}, {bb.max.x(), bb.max.y()}};
+
+    return fitIntoBoxRotation<Polygon, TCompute<Polygon>, Rational>(shape,
+                                                                    box,
+                                                                    EPSILON);
+}
+
 } // namespace Slic3r

src/libslic3r/MinAreaBoundingBox.hpp

@@ -50,6 +50,8 @@ public:
     const Point& axis()  const { return m_axis; }
 };
 
-}
+double fit_into_box_rotation(const Polygon &shape, const BoundingBox &box);
+
+} // namespace Slic3r
 
 #endif // MINAREABOUNDINGBOX_HPP

src/libslic3r/Model.cpp

@@ -1062,7 +1062,8 @@ Polygon ModelObject::convex_hull_2d(const Transform3d& trafo_instance) const
     tbb::parallel_for(tbb::blocked_range<size_t>(0, volumes.size()), [&](const tbb::blocked_range<size_t>& range) {
         for (size_t i = range.begin(); i < range.end(); ++i) {
             const ModelVolume* v = volumes[i];
-            chs.emplace_back(its_convex_hull_2d_above(v->mesh().its, (trafo_instance * v->get_matrix()).cast<float>(), 0.0f));
+            if (v->is_model_part())
+                chs.emplace_back(its_convex_hull_2d_above(v->mesh().its, (trafo_instance * v->get_matrix()).cast<float>(), 0.0f));
         }
     });
 
@@ -1280,64 +1281,6 @@ bool ModelObject::has_connectors() const
     return false;
 }
 
-indexed_triangle_set ModelObject::get_connector_mesh(CutConnectorAttributes connector_attributes)
-{
-    indexed_triangle_set connector_mesh;
-
-    int   sectorCount {1};
-    switch (CutConnectorShape(connector_attributes.shape)) {
-    case CutConnectorShape::Triangle:
-        sectorCount = 3;
-        break;
-    case CutConnectorShape::Square:
-        sectorCount = 4;
-        break;
-    case CutConnectorShape::Circle:
-        sectorCount = 360;
-        break;
-    case CutConnectorShape::Hexagon:
-        sectorCount = 6;
-        break;
-    default:
-        break;
-    }
-
-    if (connector_attributes.style == CutConnectorStyle::Prism)
-        connector_mesh = its_make_cylinder(1.0, 1.0, (2 * PI / sectorCount));
-    else if (connector_attributes.type == CutConnectorType::Plug)
-        connector_mesh = its_make_frustum(1.0, 1.0, (2 * PI / sectorCount));
-    else
-        connector_mesh = its_make_frustum_dowel(1.0, 1.0, sectorCount);
-
-    return connector_mesh;
-}
-
-void ModelObject::apply_cut_connectors(const std::string& new_name)
-{
-    if (cut_connectors.empty())
-        return;
-
-    using namespace Geometry;
-
-    size_t connector_id = cut_id.connectors_cnt();
-    for (const CutConnector& connector : cut_connectors) {
-        TriangleMesh mesh = TriangleMesh(get_connector_mesh(connector.attribs));
-        // Mesh will be centered when loading.
-        ModelVolume* new_volume = add_volume(std::move(mesh), ModelVolumeType::NEGATIVE_VOLUME);
-
-        // Transform the new modifier to be aligned inside the instance
-        new_volume->set_transformation(translation_transform(connector.pos) * connector.rotation_m *
-                                       scale_transform(Vec3f(connector.radius, connector.radius, connector.height).cast<double>()));
-
-        new_volume->cut_info = { connector.attribs.type, connector.radius_tolerance, connector.height_tolerance };
-        new_volume->name = new_name + "-" + std::to_string(++connector_id);
-    }
-    cut_id.increase_connectors_cnt(cut_connectors.size());
-
-    // delete all connectors
-    cut_connectors.clear();
-}
-
 void ModelObject::invalidate_cut()
 {
     this->cut_id.invalidate();
@@ -1390,297 +1333,6 @@ void ModelVolume::reset_extra_facets()
     this->mmu_segmentation_facets.reset();
 }
 
-void ModelVolume::apply_tolerance()
-{
-    assert(cut_info.is_connector);
-    if (!cut_info.is_processed)
-        return;
-
-    Vec3d sf = get_scaling_factor();
-
-    // make a "hole" wider
-    sf[X] += double(cut_info.radius_tolerance);
-    sf[Y] += double(cut_info.radius_tolerance);
-
-    // make a "hole" dipper
-    sf[Z] += double(cut_info.height_tolerance);
-
-    set_scaling_factor(sf);
-
-    // correct offset in respect to the new depth
-    Vec3d rot_norm = Geometry::rotation_transform(get_rotation()) * Vec3d::UnitZ();
-    if (rot_norm.norm() != 0.0)
-        rot_norm.normalize();
-
-    double z_offset = 0.5 * static_cast<double>(cut_info.height_tolerance);
-    if (cut_info.connector_type == CutConnectorType::Plug)
-        z_offset -= 0.05; // add small Z offset to better preview
-
-    set_offset(get_offset() + rot_norm * z_offset);
-}
-
-static void add_cut_volume(TriangleMesh& mesh, ModelObject* object, const ModelVolume* src_volume, const Transform3d& cut_matrix, const std::string& suffix = {}, ModelVolumeType type = ModelVolumeType::MODEL_PART)
-{
-    if (mesh.empty())
-        return;
-
-    mesh.transform(cut_matrix);
-    ModelVolume* vol = object->add_volume(mesh);
-    vol->set_type(type);
-
-    vol->name = src_volume->name + suffix;
-    // Don't copy the config's ID.
-    vol->config.assign_config(src_volume->config);
-    assert(vol->config.id().valid());
-    assert(vol->config.id() != src_volume->config.id());
-    vol->set_material(src_volume->material_id(), *src_volume->material());
-    vol->cut_info = src_volume->cut_info;
-}
-
-void ModelObject::process_connector_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix, 
-                                        ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower,
-                                        std::vector<ModelObject*>& dowels)
-{
-    assert(volume->cut_info.is_connector);
-    volume->cut_info.set_processed();
-
-    const auto volume_matrix = volume->get_matrix();
-
-    // ! Don't apply instance transformation for the conntectors.
-    // This transformation is already there
-    if (volume->cut_info.connector_type != CutConnectorType::Dowel) {
-        if (attributes.has(ModelObjectCutAttribute::KeepUpper)) {
-            ModelVolume* vol = upper->add_volume(*volume);
-            vol->set_transformation(volume_matrix);
-            vol->apply_tolerance();
-        }
-        if (attributes.has(ModelObjectCutAttribute::KeepLower)) {
-            ModelVolume* vol = lower->add_volume(*volume);
-            vol->set_transformation(volume_matrix);
-            // for lower part change type of connector from NEGATIVE_VOLUME to MODEL_PART if this connector is a plug
-            vol->set_type(ModelVolumeType::MODEL_PART);
-        }
-    }
-    else {
-        if (attributes.has(ModelObjectCutAttribute::CreateDowels)) {
-            ModelObject* dowel{ nullptr };
-            // Clone the object to duplicate instances, materials etc.
-            clone_for_cut(&dowel);
-
-            // add one more solid part same as connector if this connector is a dowel
-            ModelVolume* vol = dowel->add_volume(*volume);
-            vol->set_type(ModelVolumeType::MODEL_PART);
-
-            // But discard rotation and Z-offset for this volume
-            vol->set_rotation(Vec3d::Zero());
-            vol->set_offset(Z, 0.0);
-
-            dowels.push_back(dowel);
-        }
-
-        // Cut the dowel
-        volume->apply_tolerance();
-
-        // Perform cut
-        TriangleMesh upper_mesh, lower_mesh;
-        process_volume_cut(volume, Transform3d::Identity(), cut_matrix, attributes, upper_mesh, lower_mesh);
-
-        // add small Z offset to better preview
-        upper_mesh.translate((-0.05 * Vec3d::UnitZ()).cast<float>());
-        lower_mesh.translate((0.05 * Vec3d::UnitZ()).cast<float>());
-
-        // Add cut parts to the related objects
-        add_cut_volume(upper_mesh, upper, volume, cut_matrix, "_A", volume->type());
-        add_cut_volume(lower_mesh, lower, volume, cut_matrix, "_B", volume->type());
-    }
-}
-
-void ModelObject::process_modifier_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& inverse_cut_matrix,
-                                       ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower)
-{
-    const auto volume_matrix = instance_matrix * volume->get_matrix();
-
-    // Modifiers are not cut, but we still need to add the instance transformation
-    // to the modifier volume transformation to preserve their shape properly.
-    volume->set_transformation(Geometry::Transformation(volume_matrix));
-
-    if (attributes.has(ModelObjectCutAttribute::KeepAsParts)) {
-        upper->add_volume(*volume);
-        return;
-    }
-
-    // Some logic for the negative volumes/connectors. Add only needed modifiers
-    auto bb = volume->mesh().transformed_bounding_box(inverse_cut_matrix * volume_matrix);
-    bool is_crossed_by_cut = bb.min[Z] <= 0 && bb.max[Z] >= 0;
-    if (attributes.has(ModelObjectCutAttribute::KeepUpper) && (bb.min[Z] >= 0 || is_crossed_by_cut))
-        upper->add_volume(*volume);
-    if (attributes.has(ModelObjectCutAttribute::KeepLower) && (bb.max[Z] <= 0 || is_crossed_by_cut))
-        lower->add_volume(*volume);
-}
-
-void ModelObject::process_volume_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,
-                                     ModelObjectCutAttributes attributes, TriangleMesh& upper_mesh, TriangleMesh& lower_mesh)
-{
-    const auto volume_matrix = volume->get_matrix();
-
-    using namespace Geometry;
-
-    const Transformation cut_transformation = Transformation(cut_matrix);
-    const Transform3d invert_cut_matrix = cut_transformation.get_rotation_matrix().inverse() * translation_transform(-1 * cut_transformation.get_offset());
-
-    // Transform the mesh by the combined transformation matrix.
-    // Flip the triangles in case the composite transformation is left handed.
-    TriangleMesh mesh(volume->mesh());
-    mesh.transform(invert_cut_matrix * instance_matrix * volume_matrix, true);
-
-    indexed_triangle_set upper_its, lower_its;
-    cut_mesh(mesh.its, 0.0f, &upper_its, &lower_its);
-    if (attributes.has(ModelObjectCutAttribute::KeepUpper))
-        upper_mesh = TriangleMesh(upper_its);
-    if (attributes.has(ModelObjectCutAttribute::KeepLower))
-        lower_mesh = TriangleMesh(lower_its);
-}
-void ModelObject::process_solid_part_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,
-                                       ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower)
-{
-    // Perform cut
-    TriangleMesh upper_mesh, lower_mesh;
-    process_volume_cut(volume, instance_matrix, cut_matrix, attributes, upper_mesh, lower_mesh);
-
-    // Add required cut parts to the objects
-
-    if (attributes.has(ModelObjectCutAttribute::KeepAsParts)) {
-        add_cut_volume(upper_mesh, upper, volume, cut_matrix, "_A");
-        add_cut_volume(lower_mesh, upper, volume, cut_matrix, "_B");
-        return;
-    }
-
-    if (attributes.has(ModelObjectCutAttribute::KeepUpper))
-        add_cut_volume(upper_mesh, upper, volume, cut_matrix);
-
-    if (attributes.has(ModelObjectCutAttribute::KeepLower) && !lower_mesh.empty())
-        add_cut_volume(lower_mesh, lower, volume, cut_matrix);
-}
-
-void ModelObject::reset_instance_transformation(ModelObject* object, size_t src_instance_idx, const Transform3d& cut_matrix,
-                                                bool place_on_cut/* = false*/, bool flip/* = false*/)
-{
-    using namespace Geometry;
-
-    // Reset instance transformation except offset and Z-rotation
-
-    for (size_t i = 0; i < object->instances.size(); ++i) {
-        auto& obj_instance = object->instances[i];
-        const double rot_z = obj_instance->get_rotation().z();
-
-        Transformation inst_trafo = Transformation(obj_instance->get_transformation().get_matrix_no_scaling_factor());
-        if (obj_instance->is_left_handed())
-            inst_trafo = inst_trafo * Transformation(scale_transform(Vec3d(-1, 1, 1)));
-
-        obj_instance->set_transformation(inst_trafo);
-
-        Vec3d rotation = Vec3d::Zero();
-        if (!flip && !place_on_cut) {
-            if ( i != src_instance_idx)
-            rotation[Z] = rot_z;
-        }
-        else {
-            Transform3d rotation_matrix = Transform3d::Identity();
-            if (flip)
-                rotation_matrix = rotation_transform(PI * Vec3d::UnitX());
-
-            if (place_on_cut)
-                rotation_matrix = rotation_matrix * Transformation(cut_matrix).get_rotation_matrix().inverse();
-
-            if (i != src_instance_idx)
-                rotation_matrix = rotation_transform(rot_z * Vec3d::UnitZ()) * rotation_matrix;
-
-            rotation = Transformation(rotation_matrix).get_rotation();
-        }
-
-        obj_instance->set_rotation(rotation);
-    }
-}
-
-ModelObjectPtrs ModelObject::cut(size_t instance, const Transform3d& cut_matrix, ModelObjectCutAttributes attributes)
-{
-    if (!attributes.has(ModelObjectCutAttribute::KeepUpper) && !attributes.has(ModelObjectCutAttribute::KeepLower))
-        return {};
-
-    BOOST_LOG_TRIVIAL(trace) << "ModelObject::cut - start";
-
-    // Clone the object to duplicate instances, materials etc.
-    ModelObject* upper{ nullptr };
-    if (attributes.has(ModelObjectCutAttribute::KeepUpper))
-        clone_for_cut(&upper);
-
-    ModelObject* lower{ nullptr };
-    if (attributes.has(ModelObjectCutAttribute::KeepLower) && !attributes.has(ModelObjectCutAttribute::KeepAsParts))
-        clone_for_cut(&lower);
-
-    std::vector<ModelObject*> dowels;
-
-    using namespace Geometry;
-
-    // Because transformations are going to be applied to meshes directly,
-    // we reset transformation of all instances and volumes,
-    // except for translation and Z-rotation on instances, which are preserved
-    // in the transformation matrix and not applied to the mesh transform.
-
-    // const auto instance_matrix = instances[instance]->get_matrix(true);
-    const auto instance_matrix = instances[instance]->get_transformation().get_matrix_no_offset();
-    const Transformation cut_transformation = Transformation(cut_matrix);
-    const Transform3d inverse_cut_matrix    = cut_transformation.get_rotation_matrix().inverse() * translation_transform(-1. * cut_transformation.get_offset());
-
-    for (ModelVolume* volume : volumes) {
-        volume->reset_extra_facets();
-
-        if (!volume->is_model_part()) {
-            if (volume->cut_info.is_processed)
-                process_modifier_cut(volume, instance_matrix, inverse_cut_matrix, attributes, upper, lower);
-            else
-                process_connector_cut(volume, instance_matrix, cut_matrix, attributes, upper, lower, dowels);
-        }
-        else if (!volume->mesh().empty())
-            process_solid_part_cut(volume, instance_matrix, cut_matrix, attributes, upper, lower);
-    }
-
-    // Post-process cut parts
-
-    ModelObjectPtrs res;
-
-    if (attributes.has(ModelObjectCutAttribute::KeepAsParts) && !upper->volumes.empty()) {
-        reset_instance_transformation(upper, instance, cut_matrix);
-        res.push_back(upper);
-    }
-    else {
-        if (attributes.has(ModelObjectCutAttribute::KeepUpper) && !upper->volumes.empty()) {
-            reset_instance_transformation(upper, instance, cut_matrix,
-                attributes.has(ModelObjectCutAttribute::PlaceOnCutUpper),
-                attributes.has(ModelObjectCutAttribute::FlipUpper));
-            res.push_back(upper);
-        }
-
-        if (attributes.has(ModelObjectCutAttribute::KeepLower) && !lower->volumes.empty()) {
-            reset_instance_transformation(lower, instance, cut_matrix,
-                attributes.has(ModelObjectCutAttribute::PlaceOnCutLower),
-                attributes.has(ModelObjectCutAttribute::PlaceOnCutLower) || attributes.has(ModelObjectCutAttribute::FlipLower));
-            res.push_back(lower);
-        }
-
-        if (attributes.has(ModelObjectCutAttribute::CreateDowels) && !dowels.empty()) {
-            for (auto dowel : dowels) {
-                reset_instance_transformation(dowel, instance, Transform3d::Identity());
-                dowel->name += "-Dowel-" + dowel->volumes[0]->name;
-                res.push_back(dowel);
-            }
-        }
-    }
-
-    BOOST_LOG_TRIVIAL(trace) << "ModelObject::cut - end";
-
-    return res;
-}
 
 /// <summary>
 /// Compare TriangleMeshes by Bounding boxes (mainly for sort)
@@ -2346,38 +1998,6 @@ void ModelInstance::transform_polygon(Polygon* polygon) const
     polygon->scale(get_scaling_factor(X), get_scaling_factor(Y)); // scale around polygon origin
 }
 
-arrangement::ArrangePolygon ModelInstance::get_arrange_polygon() const
-{
-//    static const double SIMPLIFY_TOLERANCE_MM = 0.1;
-
-    Polygon p = get_object()->convex_hull_2d(this->get_matrix());
-
-//    if (!p.points.empty()) {
-//        Polygons pp{p};
-//        pp = p.simplify(scaled<double>(SIMPLIFY_TOLERANCE_MM));
-//        if (!pp.empty()) p = pp.front();
-//    }
-   
-    arrangement::ArrangePolygon ret;
-    ret.poly.contour = std::move(p);
-    ret.translation  = Vec2crd::Zero();
-    ret.rotation     = 0.;
-
-    return ret;
-}
-
-void ModelInstance::apply_arrange_result(const Vec2d &offs, double rotation)
-{
-    // write the transformation data into the model instance
-    auto trafo = get_transformation().get_matrix();
-    auto tr = Transform3d::Identity();
-    tr.translate(to_3d(unscaled(offs), 0.));
-    trafo = tr * Eigen::AngleAxisd(rotation, Vec3d::UnitZ()) * trafo;
-    m_transformation.set_matrix(trafo);
-
-    this->object->invalidate_bounding_box();
-}
-
 indexed_triangle_set FacetsAnnotation::get_facets(const ModelVolume& mv, EnforcerBlockerType type) const
 {
     TriangleSelector selector(mv.mesh());

src/libslic3r/Model.hpp

@@ -11,7 +11,6 @@
 #include "SLA/SupportPoint.hpp"
 #include "SLA/Hollowing.hpp"
 #include "TriangleMesh.hpp"
-#include "Arrange.hpp"
 #include "CustomGCode.hpp"
 #include "enum_bitmask.hpp"
 #include "TextConfiguration.hpp"
@@ -225,6 +224,7 @@ private:
 enum class CutConnectorType : int {
     Plug
     , Dowel
+    , Snap
     , Undef
 };
 
@@ -317,10 +317,6 @@ enum class ModelVolumeType : int {
     SUPPORT_ENFORCER,
 };
 
-enum class ModelObjectCutAttribute : int { KeepUpper, KeepLower, KeepAsParts, FlipUpper, FlipLower, PlaceOnCutUpper, PlaceOnCutLower, CreateDowels, InvalidateCutInfo };
-using ModelObjectCutAttributes = enum_bitmask<ModelObjectCutAttribute>;
-ENABLE_ENUM_BITMASK_OPERATORS(ModelObjectCutAttribute);
-
 // A printable object, possibly having multiple print volumes (each with its own set of parameters and materials),
 // and possibly having multiple modifier volumes, each modifier volume with its set of parameters and materials.
 // Each ModelObject may be instantiated mutliple times, each instance having different placement on the print bed,
@@ -462,29 +458,12 @@ public:
     size_t materials_count() const;
     size_t facets_count() const;
     size_t parts_count() const;
-    static indexed_triangle_set get_connector_mesh(CutConnectorAttributes connector_attributes);
-    void apply_cut_connectors(const std::string& name);
     // invalidate cut state for this object and its connectors/volumes
     void invalidate_cut();
     // delete volumes which are marked as connector for this object
     void delete_connectors();
     void clone_for_cut(ModelObject **obj);
 
-private:
-    void process_connector_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,
-                               ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower,
-                               std::vector<ModelObject*>& dowels);
-    void process_modifier_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& inverse_cut_matrix,
-                              ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower);
-    void process_volume_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,
-                            ModelObjectCutAttributes attributes, TriangleMesh& upper_mesh, TriangleMesh& lower_mesh);
-    void process_solid_part_cut(ModelVolume* volume, const Transform3d& instance_matrix, const Transform3d& cut_matrix,
-                                ModelObjectCutAttributes attributes, ModelObject* upper, ModelObject* lower);
-public:
-    static void reset_instance_transformation(ModelObject* object, size_t src_instance_idx, const Transform3d& cut_matrix,
-                                              bool place_on_cut = false, bool flip = false);
-
-    ModelObjectPtrs cut(size_t instance, const Transform3d&cut_matrix, ModelObjectCutAttributes attributes);
     void split(ModelObjectPtrs*new_objects);
     void merge();
     // Support for non-uniform scaling of instances. If an instance is rotated by angles, which are not multiples of ninety degrees,
@@ -778,6 +757,7 @@ public:
     // It contains information about connetors
     struct CutInfo
     {
+        bool                is_from_upper{ true };
         bool                is_connector{ false };
         bool                is_processed{ true };
         CutConnectorType    connector_type{ CutConnectorType::Plug };
@@ -795,6 +775,7 @@ public:
 
         void set_processed() { is_processed = true; }
         void invalidate()    { is_connector = false; }
+        void reset_from_upper() { is_from_upper = true; }
 
         template<class Archive> inline void serialize(Archive& ar) {
             ar(is_connector, is_processed, connector_type, radius_tolerance, height_tolerance);
@@ -802,6 +783,9 @@ public:
     };
     CutInfo             cut_info;
 
+    bool                is_from_upper() const    { return cut_info.is_from_upper; }
+    void                reset_from_upper()       { cut_info.reset_from_upper(); }
+
     bool                is_cut_connector() const { return cut_info.is_processed && cut_info.is_connector; }
     void                invalidate_cut_info()    { cut_info.invalidate(); }
 
@@ -851,7 +835,6 @@ public:
     bool                is_the_only_one_part() const; // behave like an object
     t_model_material_id material_id() const { return m_material_id; }
     void                reset_extra_facets();
-    void                apply_tolerance();
     void                set_material_id(t_model_material_id material_id);
     ModelMaterial*      material() const;
     void                set_material(t_model_material_id material_id, const ModelMaterial &material);
@@ -1176,11 +1159,7 @@ public:
 
     bool is_printable() const { return object->printable && printable && (print_volume_state == ModelInstancePVS_Inside); }
 
-    // Getting the input polygon for arrange
-    arrangement::ArrangePolygon get_arrange_polygon() const;
-    
-    // Apply the arrange result on the ModelInstance
-    void apply_arrange_result(const Vec2d& offs, double rotation);
+    void invalidate_object_bounding_box() { object->invalidate_bounding_box(); }
 
 protected:
     friend class Print;

src/libslic3r/ModelArrange.cpp

@@ -1,77 +1,14 @@
 #include "ModelArrange.hpp"
 
+#include <libslic3r/Arrange/SceneBuilder.hpp>
+#include <libslic3r/Arrange/Items/ArrangeItem.hpp>
+#include <libslic3r/Arrange/Tasks/MultiplySelectionTask.hpp>
+
 #include <libslic3r/Model.hpp>
 #include <libslic3r/Geometry/ConvexHull.hpp>
-#include "MTUtils.hpp"
 
 namespace Slic3r {
 
-arrangement::ArrangePolygons get_arrange_polys(const Model &model, ModelInstancePtrs &instances)
-{
-    size_t count = 0;
-    for (auto obj : model.objects) count += obj->instances.size();
-    
-    ArrangePolygons input;
-    input.reserve(count);
-    instances.clear(); instances.reserve(count);
-    for (ModelObject *mo : model.objects)
-        for (ModelInstance *minst : mo->instances) {
-            input.emplace_back(minst->get_arrange_polygon());
-            instances.emplace_back(minst);
-        }
-    
-    return input;
-}
-
-bool apply_arrange_polys(ArrangePolygons &input, ModelInstancePtrs &instances, VirtualBedFn vfn)
-{
-    bool ret = true;
-    
-    for(size_t i = 0; i < input.size(); ++i) {
-        if (input[i].bed_idx != 0) { ret = false; if (vfn) vfn(input[i]); }
-        if (input[i].bed_idx >= 0)
-            instances[i]->apply_arrange_result(input[i].translation.cast<double>(),
-                                               input[i].rotation);
-    }
-    
-    return ret;
-}
-
-Slic3r::arrangement::ArrangePolygon get_arrange_poly(const Model &model)
-{
-    ArrangePolygon ap;
-    Points &apts = ap.poly.contour.points;
-    for (const ModelObject *mo : model.objects)
-        for (const ModelInstance *minst : mo->instances) {
-            ArrangePolygon obj_ap = minst->get_arrange_polygon();
-            ap.poly.contour.rotate(obj_ap.rotation);
-            ap.poly.contour.translate(obj_ap.translation.x(), obj_ap.translation.y());
-            const Points &pts = obj_ap.poly.contour.points;
-            std::copy(pts.begin(), pts.end(), std::back_inserter(apts));
-        }
-    
-    apts = std::move(Geometry::convex_hull(apts).points);
-    return ap;
-}
-
-void duplicate(Model &model, Slic3r::arrangement::ArrangePolygons &copies, VirtualBedFn vfn)
-{
-    for (ModelObject *o : model.objects) {
-        // make a copy of the pointers in order to avoid recursion when appending their copies
-        ModelInstancePtrs instances = o->instances;
-        o->instances.clear();
-        for (const ModelInstance *i : instances) {
-            for (arrangement::ArrangePolygon &ap : copies) {
-                if (ap.bed_idx != 0) vfn(ap);
-                ModelInstance *instance = o->add_instance(*i);
-                Vec2d pos = unscale(ap.translation);
-                instance->set_offset(instance->get_offset() + to_3d(pos, 0.));
-            }
-        }
-        o->invalidate_bounding_box();
-    }
-}
-
 void duplicate_objects(Model &model, size_t copies_num)
 {
     for (ModelObject *o : model.objects) {
@@ -83,4 +20,45 @@ void duplicate_objects(Model &model, size_t copies_num)
     }
 }
 
+bool arrange_objects(Model &model,
+                     const arr2::ArrangeBed &bed,
+                     const arr2::ArrangeSettingsView &settings)
+{
+    return arrange(arr2::SceneBuilder{}
+                       .set_bed(bed)
+                       .set_arrange_settings(settings)
+                       .set_model(model));
+}
+
+void duplicate_objects(Model &model,
+                       size_t copies_num,
+                       const arr2::ArrangeBed &bed,
+                       const arr2::ArrangeSettingsView &settings)
+{
+    duplicate_objects(model, copies_num);
+    arrange_objects(model, bed, settings);
+}
+
+void duplicate(Model &model,
+               size_t copies_num,
+               const arr2::ArrangeBed &bed,
+               const arr2::ArrangeSettingsView &settings)
+{
+    auto vbh = arr2::VirtualBedHandler::create(bed);
+    arr2::DuplicableModel dup_model{&model, std::move(vbh), bounding_box(bed)};
+
+    arr2::Scene scene{arr2::BasicSceneBuilder{}
+                          .set_arrangeable_model(&dup_model)
+                          .set_arrange_settings(&settings)
+                          .set_bed(bed)};
+
+    if (copies_num >= 1)
+        copies_num -= 1;
+
+    auto task = arr2::MultiplySelectionTask<arr2::ArrangeItem>::create(scene, copies_num);
+    auto result = task->process_native(arr2::DummyCtl{});
+    if (result->apply_on(scene.model()))
+        dup_model.apply_duplicates();
+}
+
 } // namespace Slic3r

src/libslic3r/ModelArrange.hpp

@@ -1,7 +1,7 @@
 #ifndef MODELARRANGE_HPP
 #define MODELARRANGE_HPP
 
-#include <libslic3r/Arrange.hpp>
+#include <libslic3r/Arrange/Scene.hpp>
 
 namespace Slic3r {
 
@@ -9,63 +9,23 @@ class Model;
 class ModelInstance;
 using ModelInstancePtrs = std::vector<ModelInstance*>;
 
-using arrangement::ArrangePolygon;
-using arrangement::ArrangePolygons;
-using arrangement::ArrangeParams;
-using arrangement::InfiniteBed;
-using arrangement::CircleBed;
-
-// Do something with ArrangePolygons in virtual beds
-using VirtualBedFn = std::function<void(arrangement::ArrangePolygon&)>;
-
-[[noreturn]] inline void throw_if_out_of_bed(arrangement::ArrangePolygon&) 
-{
-    throw Slic3r::RuntimeError("Objects could not fit on the bed");
-}
-
-ArrangePolygons get_arrange_polys(const Model &model, ModelInstancePtrs &instances);
-ArrangePolygon  get_arrange_poly(const Model &model);
-bool apply_arrange_polys(ArrangePolygons &polys, ModelInstancePtrs &instances, VirtualBedFn);
-
-void duplicate(Model &model, ArrangePolygons &copies, VirtualBedFn);
+//void duplicate(Model &model, ArrangePolygons &copies, VirtualBedFn);
 void duplicate_objects(Model &model, size_t copies_num);
 
-template<class TBed>
-bool arrange_objects(Model &              model,
-                     const TBed &         bed,
-                     const ArrangeParams &params,
-                     VirtualBedFn         vfn = throw_if_out_of_bed)
-{
-    ModelInstancePtrs instances;
-    auto&& input = get_arrange_polys(model, instances);
-    arrangement::arrange(input, bed, params);
-    
-    return apply_arrange_polys(input, instances, vfn);
-}
+bool arrange_objects(Model &model,
+                     const arr2::ArrangeBed &bed,
+                     const arr2::ArrangeSettingsView &settings);
 
-template<class TBed>
-void duplicate(Model &              model,
-               size_t               copies_num,
-               const TBed &         bed,
-               const ArrangeParams &params,
-               VirtualBedFn         vfn = throw_if_out_of_bed)
-{
-    ArrangePolygons copies(copies_num, get_arrange_poly(model));
-    arrangement::arrange(copies, bed, params);
-    duplicate(model, copies, vfn);
-}
-
-template<class TBed>
 void duplicate_objects(Model &              model,
                        size_t               copies_num,
-                       const TBed &         bed,
-                       const ArrangeParams &params,
-                       VirtualBedFn         vfn = throw_if_out_of_bed)
-{
-    duplicate_objects(model, copies_num);
-    arrange_objects(model, bed, params, vfn);
-}
+                       const arr2::ArrangeBed &bed,
+                       const arr2::ArrangeSettingsView &settings);
 
-}
+void duplicate(Model &              model,
+               size_t               copies_num,
+               const arr2::ArrangeBed &bed,
+               const arr2::ArrangeSettingsView &settings);
+
+} // namespace Slic3r
 
 #endif // MODELARRANGE_HPP

src/libslic3r/MultiMaterialSegmentation.cpp

@@ -1271,18 +1271,23 @@ static void remove_multiple_edges_in_vertices(MMU_Graph &graph, const std::vecto
 static void cut_segmented_layers(const std::vector<ExPolygons>        &input_expolygons,
                                  std::vector<std::vector<ExPolygons>> &segmented_regions,
                                  const float                           cut_width,
+                                 const float                           interlocking_depth,
                                  const std::function<void()>          &throw_on_cancel_callback)
 {
     BOOST_LOG_TRIVIAL(debug) << "MMU segmentation - cutting segmented layers in parallel - begin";
-    tbb::parallel_for(tbb::blocked_range<size_t>(0, segmented_regions.size()),[&segmented_regions, &input_expolygons, &cut_width, &throw_on_cancel_callback](const tbb::blocked_range<size_t>& range) {
+    const float interlocking_cut_width = interlocking_depth > 0.f ? std::max(cut_width - interlocking_depth, 0.f) : 0.f;
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, segmented_regions.size()),[&segmented_regions, &input_expolygons, &cut_width, &interlocking_cut_width, &throw_on_cancel_callback](const tbb::blocked_range<size_t>& range) {
         for (size_t layer_idx = range.begin(); layer_idx < range.end(); ++layer_idx) {
             throw_on_cancel_callback();
-            const size_t            num_extruders_plus_one = segmented_regions[layer_idx].size();
-            std::vector<ExPolygons> segmented_regions_cuts(num_extruders_plus_one); // Indexed by extruder_id
-            for (size_t extruder_idx = 0; extruder_idx < num_extruders_plus_one; ++extruder_idx)
-                if (const ExPolygons &ex_polygons = segmented_regions[layer_idx][extruder_idx]; !ex_polygons.empty())
-                    segmented_regions_cuts[extruder_idx] = diff_ex(ex_polygons, offset_ex(input_expolygons[layer_idx], cut_width));
-            segmented_regions[layer_idx] = std::move(segmented_regions_cuts);
+            const float  region_cut_width       = (layer_idx % 2 == 0 && interlocking_cut_width > 0.f) ? interlocking_cut_width : cut_width;
+            const size_t num_extruders_plus_one = segmented_regions[layer_idx].size();
+            if (region_cut_width > 0.f) {
+                std::vector<ExPolygons> segmented_regions_cuts(num_extruders_plus_one); // Indexed by extruder_id
+                for (size_t extruder_idx = 0; extruder_idx < num_extruders_plus_one; ++extruder_idx)
+                    if (const ExPolygons &ex_polygons = segmented_regions[layer_idx][extruder_idx]; !ex_polygons.empty())
+                        segmented_regions_cuts[extruder_idx] = diff_ex(ex_polygons, offset_ex(input_expolygons[layer_idx], -region_cut_width));
+                segmented_regions[layer_idx] = std::move(segmented_regions_cuts);
+            }
         }
     }); // end of parallel_for
     BOOST_LOG_TRIVIAL(debug) << "MMU segmentation - cutting segmented layers in parallel - end";
@@ -1891,8 +1896,8 @@ std::vector<std::vector<ExPolygons>> multi_material_segmentation_by_painting(con
     BOOST_LOG_TRIVIAL(debug) << "MMU segmentation - layers segmentation in parallel - end";
     throw_on_cancel_callback();
 
-    if (auto w = print_object.config().mmu_segmented_region_max_width; w > 0.f) {
-        cut_segmented_layers(input_expolygons, segmented_regions, float(-scale_(w)), throw_on_cancel_callback);
+    if (auto max_width = print_object.config().mmu_segmented_region_max_width, interlocking_depth = print_object.config().mmu_segmented_region_interlocking_depth; max_width > 0.f) {
+        cut_segmented_layers(input_expolygons, segmented_regions, float(scale_(max_width)), float(scale_(interlocking_depth)), throw_on_cancel_callback);
         throw_on_cancel_callback();
     }
 

src/libslic3r/MultiPoint.hpp

@@ -90,6 +90,12 @@ public:
     inline auto end()    const { return points.end();   }
     inline auto cbegin() const { return points.begin(); }
     inline auto cend()   const { return points.end();   }
+    inline auto rbegin()       { return points.rbegin(); }
+    inline auto rbegin() const { return points.rbegin(); }
+    inline auto rend()         { return points.rend();   }
+    inline auto rend()   const { return points.rend();   }
+    inline auto crbegin()const { return points.crbegin(); }
+    inline auto crend()  const { return points.crend(); }
 };
 
 class MultiPoint3

src/libslic3r/OpenVDBUtils.cpp

@@ -1,4 +1,3 @@
-#define NOMINMAX
 #include "OpenVDBUtils.hpp"
 
 #ifdef _MSC_VER

src/libslic3r/Optimize/NLoptOptimizer.hpp

@@ -13,6 +13,8 @@
 
 #include <utility>
 
+#include <libslic3r/libslic3r.h>
+
 #include "Optimizer.hpp"
 
 namespace Slic3r { namespace opt {
@@ -104,29 +106,6 @@ struct NLoptRAII { // Helper RAII class for nlopt_opt
     ~NLoptRAII() { nlopt_destroy(ptr); }
 };
 
-// Map a generic function to each argument following the mapping function
-template<class Fn, class...Args>
-Fn for_each_argument(Fn &&fn, Args&&...args)
-{
-    // see https://www.fluentcpp.com/2019/03/05/for_each_arg-applying-a-function-to-each-argument-of-a-function-in-cpp/
-    (fn(std::forward<Args>(args)),...);
-
-    return fn;
-}
-
-// Call fn on each element of the input tuple tup.
-template<class Fn, class Tup>
-Fn for_each_in_tuple(Fn fn, Tup &&tup)
-{
-    auto mpfn = [&fn](auto&...pack) {
-        for_each_argument(fn, pack...);
-    };
-
-    std::apply(mpfn, tup);
-
-    return fn;
-}
-
 // Wrap each element of the tuple tup into a wrapper class W and return
 // a new tuple with each element being of type W<T_i> where T_i is the type of
 // i-th element of tup.

src/libslic3r/Optimize/Optimizer.hpp

@@ -1,5 +1,5 @@
-#ifndef OPTIMIZER_HPP
-#define OPTIMIZER_HPP
+#ifndef PRUSASLICER_OPTIMIZER_HPP
+#define PRUSASLICER_OPTIMIZER_HPP
 
 #include <utility>
 #include <tuple>
@@ -10,6 +10,11 @@
 #include <cassert>
 #include <optional>
 
+#ifdef WIN32
+#undef min
+#undef max
+#endif
+
 namespace Slic3r { namespace opt {
 
 template<class T, class O = T>

src/libslic3r/Polygon.hpp

@@ -287,6 +287,12 @@ struct PolygonPoint
 };
 using PolygonPoints = std::vector<PolygonPoint>;
 
+// To replace reserve_vector where it's used for Polygons
+template<class I> IntegerOnly<I, Polygons> reserve_polygons(I cap)
+{
+    return reserve_vector<Polygon, I, typename Polygons::allocator_type>(cap);
+}
+
 } // Slic3r
 
 // start Boost

src/libslic3r/Polyline.hpp

@@ -78,6 +78,9 @@ public:
     void split_at(const Point &point, Polyline* p1, Polyline* p2) const;
     bool is_straight() const;
     bool is_closed() const { return this->points.front() == this->points.back(); }
+
+    using iterator = Points::iterator;
+    using const_iterator = Points::const_iterator;
 };
 
 inline bool operator==(const Polyline &lhs, const Polyline &rhs) { return lhs.points == rhs.points; }

src/libslic3r/Preset.cpp

@@ -7,7 +7,9 @@
 
 #ifdef _MSC_VER
     #define WIN32_LEAN_AND_MEAN
+#ifndef NOMINMAX
     #define NOMINMAX
+#endif
     #include <Windows.h>
 #endif /* _MSC_VER */
 
@@ -456,7 +458,7 @@ static std::vector<std::string> s_Preset_print_options {
     "top_infill_extrusion_width", "support_material_extrusion_width", "infill_overlap", "infill_anchor", "infill_anchor_max", "bridge_flow_ratio",
     "elefant_foot_compensation", "xy_size_compensation", "threads", "resolution", "gcode_resolution", "wipe_tower", "wipe_tower_x", "wipe_tower_y",
     "wipe_tower_width", "wipe_tower_cone_angle", "wipe_tower_rotation_angle", "wipe_tower_brim_width", "wipe_tower_bridging", "single_extruder_multi_material_priming", "mmu_segmented_region_max_width",
-    "wipe_tower_extruder", "wipe_tower_no_sparse_layers", "wipe_tower_extra_spacing", "compatible_printers", "compatible_printers_condition", "inherits",
+    "mmu_segmented_region_interlocking_depth", "wipe_tower_extruder", "wipe_tower_no_sparse_layers", "wipe_tower_extra_spacing", "compatible_printers", "compatible_printers_condition", "inherits",
     "perimeter_generator", "wall_transition_length", "wall_transition_filter_deviation", "wall_transition_angle",
     "wall_distribution_count", "min_feature_size", "min_bead_width"
 };
@@ -466,13 +468,14 @@ static std::vector<std::string> s_Preset_filament_options {
     "extrusion_multiplier", "filament_density", "filament_cost", "filament_spool_weight", "filament_loading_speed", "filament_loading_speed_start", "filament_load_time",
     "filament_unloading_speed", "filament_unloading_speed_start", "filament_unload_time", "filament_toolchange_delay", "filament_cooling_moves",
     "filament_cooling_initial_speed", "filament_cooling_final_speed", "filament_ramming_parameters", "filament_minimal_purge_on_wipe_tower",
+    "filament_multitool_ramming", "filament_multitool_ramming_volume", "filament_multitool_ramming_flow", 
     "temperature", "idle_temperature", "first_layer_temperature", "bed_temperature", "first_layer_bed_temperature", "fan_always_on", "cooling", "min_fan_speed",
     "max_fan_speed", "bridge_fan_speed", "disable_fan_first_layers", "full_fan_speed_layer", "fan_below_layer_time", "slowdown_below_layer_time", "min_print_speed",
     "start_filament_gcode", "end_filament_gcode", "enable_dynamic_fan_speeds",
     "overhang_fan_speed_0", "overhang_fan_speed_1", "overhang_fan_speed_2", "overhang_fan_speed_3",
     // Retract overrides
     "filament_retract_length", "filament_retract_lift", "filament_retract_lift_above", "filament_retract_lift_below", "filament_retract_speed", "filament_deretract_speed", "filament_retract_restart_extra", "filament_retract_before_travel",
-    "filament_retract_layer_change", "filament_wipe", "filament_retract_before_wipe",
+    "filament_retract_layer_change", "filament_wipe", "filament_retract_before_wipe", "filament_retract_length_toolchange", "filament_retract_restart_extra_toolchange",
     // Profile compatibility
     "filament_vendor", "compatible_prints", "compatible_prints_condition", "compatible_printers", "compatible_printers_condition", "inherits"
 };

src/libslic3r/Print.cpp

@@ -194,6 +194,9 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
             || opt_key == "filament_cooling_initial_speed"
             || opt_key == "filament_cooling_final_speed"
             || opt_key == "filament_ramming_parameters"
+            || opt_key == "filament_multitool_ramming"
+            || opt_key == "filament_multitool_ramming_volume"
+            || opt_key == "filament_multitool_ramming_flow"
             || opt_key == "filament_max_volumetric_speed"
             || opt_key == "gcode_flavor"
             || opt_key == "high_current_on_filament_swap"
@@ -900,20 +903,29 @@ void Print::process()
     name_tbb_thread_pool_threads_set_locale();
 
     BOOST_LOG_TRIVIAL(info) << "Starting the slicing process." << log_memory_info();
-    for (PrintObject *obj : m_objects)
-        obj->make_perimeters();
-    for (PrintObject *obj : m_objects)
-        obj->infill();
-    for (PrintObject *obj : m_objects)
-        obj->ironing();
+
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, m_objects.size(), 1), [this](const tbb::blocked_range<size_t> &range) {
+        for (size_t idx = range.begin(); idx < range.end(); ++idx) {
+            m_objects[idx]->make_perimeters();
+            m_objects[idx]->infill();
+            m_objects[idx]->ironing();
+        }
+    }, tbb::simple_partitioner());
+
+    // The following step writes to m_shared_regions, it should not run in parallel.
     for (PrintObject *obj : m_objects)
         obj->generate_support_spots();
     // check data from previous step, format the error message(s) and send alert to ui
+    // this also has to be done sequentially.
     alert_when_supports_needed();
-    for (PrintObject *obj : m_objects)
-        obj->generate_support_material();
-    for (PrintObject *obj : m_objects)
-        obj->estimate_curled_extrusions();
+
+    tbb::parallel_for(tbb::blocked_range<size_t>(0, m_objects.size(), 1), [this](const tbb::blocked_range<size_t> &range) {
+        for (size_t idx = range.begin(); idx < range.end(); ++idx) {
+            m_objects[idx]->generate_support_material();
+            m_objects[idx]->estimate_curled_extrusions();
+        }
+    }, tbb::simple_partitioner());
+
     if (this->set_started(psWipeTower)) {
         m_wipe_tower_data.clear();
         m_tool_ordering.clear();

src/libslic3r/PrintConfig.cpp

@@ -1103,6 +1103,30 @@ void PrintConfigDef::init_fff_params()
     def->mode = comExpert;
     def->set_default_value(new ConfigOptionFloats { 0. });
 
+    def = this->add("filament_multitool_ramming", coBools);
+    def->label = L("Enable ramming for multitool setups");
+    def->tooltip = L("Perform ramming when using multitool printer (i.e. when the 'Single Extruder Multimaterial' in Printer Settings is unchecked). "
+                     "When checked, a small amount of filament is rapidly extruded on the wipe tower just before the toolchange. "
+                     "This option is only used when the wipe tower is enabled.");
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionBools { false });
+
+    def = this->add("filament_multitool_ramming_volume", coFloats);
+    def->label = L("Multitool ramming volume");
+    def->tooltip = L("The volume to be rammed before the toolchange.");
+    def->sidetext = L("mm³");
+    def->min = 0;
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionFloats { 10. });
+
+    def = this->add("filament_multitool_ramming_flow", coFloats);
+    def->label = L("Multitool ramming flow");
+    def->tooltip = L("Flow used for ramming the filament before the toolchange.");
+    def->sidetext = L("mm³/s");
+    def->min = 0;
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionFloats { 10. });
+
     def = this->add("filament_diameter", coFloats);
     def->label = L("Diameter");
     def->tooltip = L("Enter your filament diameter here. Good precision is required, so use a caliper "
@@ -1621,6 +1645,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comExpert;
     def->set_default_value(new ConfigOptionFloat(0.));
 
+    def = this->add("mmu_segmented_region_interlocking_depth", coFloat);
+    def->label = L("Interlocking depth of a segmented region");
+    def->tooltip = L("Interlocking depth of a segmented region. It will be ignored if "
+                       "\"mmu_segmented_region_max_width\" is zero or if \"mmu_segmented_region_interlocking_depth\""
+                       "is bigger then \"mmu_segmented_region_max_width\". Zero disables this feature.");
+    def->sidetext = L("mm (zero to disable)");
+    def->min = 0;
+    def->category = L("Advanced");
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionFloat(0.));
+
     def = this->add("ironing", coBool);
     def->label = L("Enable ironing");
     def->tooltip = L("Enable ironing of the top layers with the hot print head for smooth surface");
@@ -3365,7 +3400,8 @@ void PrintConfigDef::init_fff_params()
     // Declare retract values for filament profile, overriding the printer's extruder profile.
     for (const char *opt_key : {
         // floats
-        "retract_length", "retract_lift", "retract_lift_above", "retract_lift_below", "retract_speed", "deretract_speed", "retract_restart_extra", "retract_before_travel",
+        "retract_length", "retract_lift", "retract_lift_above", "retract_lift_below", "retract_speed",
+        "deretract_speed", "retract_restart_extra", "retract_before_travel", "retract_length_toolchange", "retract_restart_extra_toolchange",
         // bools
         "retract_layer_change", "wipe",
         // percents
@@ -3404,10 +3440,12 @@ void PrintConfigDef::init_extruder_option_keys()
         "retract_before_wipe",
         "retract_layer_change",
         "retract_length",
+        "retract_length_toolchange",
         "retract_lift",
         "retract_lift_above",
         "retract_lift_below",
         "retract_restart_extra",
+        "retract_restart_extra_toolchange",
         "retract_speed",
         "wipe"
     };
@@ -4285,6 +4323,13 @@ void PrintConfigDef::handle_legacy(t_config_option_key &opt_key, std::string &va
     }
 }
 
+// Called after a config is loaded as a whole.
+// Perform composite conversions, for example merging multiple keys into one key.
+// Don't convert single options here, implement such conversion in PrintConfigDef::handle_legacy() instead.
+void PrintConfigDef::handle_legacy_composite(DynamicPrintConfig &config)
+{
+}
+
 const PrintConfigDef print_config_def;
 
 DynamicPrintConfig DynamicPrintConfig::full_print_config()
@@ -4651,9 +4696,11 @@ std::string validate(const FullPrintConfig &cfg)
     BOOST_PP_SEQ_FOR_EACH(PRINT_CONFIG_CACHE_ELEMENT_DEFINITION, _, BOOST_PP_TUPLE_TO_SEQ(CLASSES_SEQ)) \
     int print_config_static_initializer() { \
         /* Putting a trace here to avoid the compiler to optimize out this function. */ \
-        BOOST_LOG_TRIVIAL(trace) << "Initializing StaticPrintConfigs"; \
+        /*BOOST_LOG_TRIVIAL(trace) << "Initializing StaticPrintConfigs";*/ \
+        /* Tamas: alternative solution through a static volatile int. Boost log pollutes stdout and prevents tests from generating clean output */ \
+        static volatile int ret = 1; \
         BOOST_PP_SEQ_FOR_EACH(PRINT_CONFIG_CACHE_ELEMENT_INITIALIZATION, _, BOOST_PP_TUPLE_TO_SEQ(CLASSES_SEQ)) \
-        return 1; \
+        return ret; \
     }
 PRINT_CONFIG_CACHE_INITIALIZE((
     PrintObjectConfig, PrintRegionConfig, MachineEnvelopeConfig, GCodeConfig, PrintConfig, FullPrintConfig, 
@@ -4949,15 +4996,6 @@ Points get_bed_shape(const DynamicPrintConfig &config)
     return to_points(bed_shape_opt->values);
 }
 
-void get_bed_shape(const DynamicPrintConfig &cfg, arrangement::ArrangeBed &out)
-{
-    if (is_XL_printer(cfg)) {
-        out = arrangement::SegmentedRectangleBed{get_extents(get_bed_shape(cfg)), 4, 4};
-    } else {
-        out = arrangement::to_arrange_bed(get_bed_shape(cfg));
-    }
-}
-
 Points get_bed_shape(const PrintConfig &cfg)
 {
     return to_points(cfg.bed_shape.values);