New feature: brim connections

lib/Slic3r/GUI/3DScene.pm

@@ -1285,7 +1285,9 @@ sub load_print_toolpaths {
     
     return if !$print->step_done(STEP_SKIRT);
     return if !$print->step_done(STEP_BRIM);
-    return if !$print->has_skirt && $print->config->brim_width == 0;
+    return if !$print->has_skirt
+        && $print->config->brim_width == 0
+        && $print->config->brim_connections_width == 0;
     
     my $qverts  = Slic3r::GUI::_3DScene::GLVertexArray->new;
     my $tverts  = Slic3r::GUI::_3DScene::GLVertexArray->new;

lib/Slic3r/GUI/Tab.pm

@@ -479,7 +479,7 @@ sub build {
         perimeter_acceleration infill_acceleration bridge_acceleration 
         first_layer_acceleration default_acceleration
         skirts skirt_distance skirt_height min_skirt_length
-        brim_width
+        brim_connections_width brim_width
         support_material support_material_threshold support_material_enforce_layers
         raft_layers
         support_material_pattern support_material_spacing support_material_angle
@@ -571,6 +571,7 @@ sub build {
         {
             my $optgroup = $page->new_optgroup('Brim');
             $optgroup->append_single_option_line('brim_width');
+            $optgroup->append_single_option_line('brim_connections_width');
         }
     }
     
@@ -848,7 +849,7 @@ sub _update {
     $self->get_field($_)->toggle($have_skirt)
         for qw(skirt_distance skirt_height);
     
-    my $have_brim = $config->brim_width > 0;
+    my $have_brim = $config->brim_width > 0 || $config->brim_connections_width;
     # perimeter_extruder uses the same logic as in Print::extruders()
     $self->get_field('perimeter_extruder')->toggle($have_perimeters || $have_brim);
     

lib/Slic3r/Print.pm

@@ -12,8 +12,9 @@ use Slic3r::ExtrusionPath ':roles';
 use Slic3r::Flow ':roles';
 use Slic3r::Geometry qw(X Y Z X1 Y1 X2 Y2 MIN MAX PI scale unscale convex_hull);
 use Slic3r::Geometry::Clipper qw(diff_ex union_ex intersection_ex intersection offset
-    offset2 union union_pt_chained JT_ROUND JT_SQUARE);
+    offset2 union union_pt_chained JT_ROUND JT_SQUARE diff_pl);
 use Slic3r::Print::State ':steps';
+use Slic3r::Surface qw(S_TYPE_BOTTOM);
 
 our $status_cb;
 
@@ -356,7 +357,7 @@ sub make_brim {
     # checking whether we need to generate them
     $self->brim->clear;
     
-    if ($self->config->brim_width == 0) {
+    if ($self->config->brim_width == 0 && $self->config->brim_connections_width == 0) {
         $self->set_step_done(STEP_BRIM);
         return;
     }
@@ -390,7 +391,7 @@ sub make_brim {
     }
     
     my @loops = ();
-    my $num_loops = sprintf "%.0f", $self->config->brim_width / $flow->width;
+    my $num_loops = int($self->config->brim_width / $flow->width + 0.5);
     for my $i (reverse 1 .. $num_loops) {
         # JT_SQUARE ensures no vertex is outside the given offset distance
         # -0.5 because islands are not represented by their centerlines
@@ -409,6 +410,65 @@ sub make_brim {
         ),
     ), reverse @{union_pt_chained(\@loops)});
     
+    if ($self->config->brim_connections_width > 0) {
+        # get islands to connects
+        @islands = map convex_hull(\@$_), @islands;
+        @islands = @{offset(\@islands, ($num_loops-0.2) * $flow->scaled_spacing, 10000, JT_SQUARE)};
+        
+        # compute centroid for each island
+        my @centroids = map $_->centroid, @islands;
+        
+        # in order to check visibility we need to account for the connections width,
+        # so let's use grown islands
+        my $scaled_width = scale($self->config->brim_connections_width);
+        my $grown = offset(\@islands, +$scaled_width/2);
+        
+        # find pairs of islands having direct visibility
+        my @lines = ();
+        for my $i (0..$#islands) {
+            for my $j (($i+1)..$#islands) {
+                # check visibility
+                my $line = Slic3r::Line->new(@centroids[$i,$j]);
+                next if @{diff_pl([$line->as_polyline], $grown)} != 1;
+                
+                push @lines, $line;
+            }
+        }
+        
+        my $filler = Slic3r::Filler->new_from_type('rectilinear');
+        $filler->set_spacing($flow->spacing);
+        $filler->set_dont_adjust(1);
+        
+        # subtract already generated connections in order to prevent crossings
+        # and overextrusion
+        my @other = ();
+        
+        foreach my $line (@lines) {
+            my $expolygons = diff_ex(
+                $line->grow($scaled_width/2),
+                [ @islands, @other ],
+            );
+            push @other, map $_->clone, map @$_, @$expolygons;
+            
+            $filler->set_angle($line->direction);
+            foreach my $expolygon (@$expolygons) {
+                my $paths = $filler->fill_surface(
+                    Slic3r::Surface->new(expolygon => $expolygon, surface_type => S_TYPE_BOTTOM),
+                    layer_height    => $first_layer_height,
+                    density         => 1,
+                );
+            
+                $self->brim->append(map Slic3r::ExtrusionPath->new(
+                    polyline        => $_,
+                    role            => EXTR_ROLE_SKIRT,
+                    mm3_per_mm      => $mm3_per_mm,
+                    width           => $flow->width,
+                    height          => $first_layer_height,
+                ), @$paths);
+            }
+        }
+    }
+    
     $self->set_step_done(STEP_BRIM);
 }
 

lib/Slic3r/Print/GCode.pm

@@ -357,7 +357,7 @@ sub process_layer {
     # check whether we're going to apply spiralvase logic
     if (defined $self->_spiral_vase) {
         $self->_spiral_vase->enable(
-            ($layer->id > 0 || $self->print->config->brim_width == 0)
+            ($layer->id > 0 || $self->print->config->brim_width == 0 || $self->print->config->brim_connections_width == 0)
                 && ($layer->id >= $self->print->config->skirt_height && !$self->print->has_infinite_skirt)
                 && !defined(first { $_->region->config->bottom_solid_layers > $layer->id } @{$layer->regions})
                 && !defined(first { $_->perimeters->items_count > 1 } @{$layer->regions})
@@ -447,7 +447,7 @@ sub process_layer {
         $gcode .= $self->_gcodegen->set_extruder($self->print->regions->[0]->config->perimeter_extruder-1);
         $self->_gcodegen->set_origin(Slic3r::Pointf->new(0,0));
         $self->_gcodegen->avoid_crossing_perimeters->set_use_external_mp(1);
-        $gcode .= $self->_gcodegen->extrude_loop($_, 'brim', $object->config->support_material_speed)
+        $gcode .= $self->_gcodegen->extrude($_, 'brim', $object->config->support_material_speed)
             for @{$self->print->brim};
         $self->_brim_done(1);
         $self->_gcodegen->avoid_crossing_perimeters->set_use_external_mp(0);

xs/src/libslic3r/Print.cpp

@@ -163,7 +163,8 @@ Print::invalidate_state_by_config_options(const std::vector<t_config_option_key>
             || *opt_key == "min_skirt_length"
             || *opt_key == "ooze_prevention") {
             steps.insert(psSkirt);
-        } else if (*opt_key == "brim_width") {
+        } else if (*opt_key == "brim_width"
+            || *opt_key == "brim_connections_width") {
             steps.insert(psBrim);
             steps.insert(psSkirt);
         } else if (*opt_key == "nozzle_diameter"
@@ -304,7 +305,7 @@ Print::object_extruders() const
     FOREACH_REGION(this, region) {
         // these checks reflect the same logic used in the GUI for enabling/disabling
         // extruder selection fields
-        if ((*region)->config.perimeters.value > 0 || this->config.brim_width.value > 0)
+        if ((*region)->config.perimeters.value > 0 || this->config.brim_width.value > 0 || this->config.brim_connections_width.value > 0)
             extruders.insert((*region)->config.perimeter_extruder - 1);
         
         if ((*region)->config.fill_density.value > 0)

xs/src/libslic3r/PrintConfig.cpp

@@ -91,6 +91,14 @@ PrintConfigDef::PrintConfigDef()
     def->min = 0;
     def->default_value = new ConfigOptionFloat(60);
 
+    def = this->add("brim_connections_width", coFloat);
+    def->label = "Brim connections width";
+    def->tooltip = "If set to a positive value, straight connections will be built on the first layer between adjacent objects.";
+    def->sidetext = "mm";
+    def->cli = "brim-connections-width=f";
+    def->min = 0;
+    def->default_value = new ConfigOptionFloat(0);
+
     def = this->add("brim_width", coFloat);
     def->label = "Brim width";
     def->tooltip = "Horizontal width of the brim that will be printed around each object on the first layer.";

xs/src/libslic3r/PrintConfig.hpp

@@ -366,6 +366,7 @@ class PrintConfig : public GCodeConfig
     ConfigOptionInt                 bed_temperature;
     ConfigOptionFloat               bridge_acceleration;
     ConfigOptionInt                 bridge_fan_speed;
+    ConfigOptionFloat               brim_connections_width;
     ConfigOptionFloat               brim_width;
     ConfigOptionBool                complete_objects;
     ConfigOptionBool                cooling;
@@ -425,6 +426,7 @@ class PrintConfig : public GCodeConfig
         OPT_PTR(bed_temperature);
         OPT_PTR(bridge_acceleration);
         OPT_PTR(bridge_fan_speed);
+        OPT_PTR(brim_connections_width);
         OPT_PTR(brim_width);
         OPT_PTR(complete_objects);
         OPT_PTR(cooling);