#612 add soft threshold for big holes XY compensation

resources/ui_layout/print.ui

@@ -86,12 +86,15 @@ group:label_width$8:Modifying slices
 		setting:width$6:curve_smoothing_angle_concave
 		setting:width$6:curve_smoothing_cutoff_dist
 	end_line
-	setting:hole_to_polyhole
 	line:XY compensation
 		setting:width$6:xy_size_compensation
 		setting:width$6:xy_inner_size_compensation
 		setting:width$6:first_layer_size_compensation
+	end_line
+	line:Vertical Hole shrinking compensation
+		setting:hole_to_polyhole
 		setting:width$6:hole_size_compensation
+		setting:width$6:hole_size_threshold
 	end_line
 group:Other
 	setting:clip_multipart_objects

src/libslic3r/PrintConfig.cpp

@@ -3725,7 +3725,8 @@ void PrintConfigDef::init_fff_params()
     def->category = OptionCategory::slicing;
     def->tooltip = L("The object will be grown/shrunk in the XY plane by the configured value "
         "(negative = inwards, positive = outwards). This might be useful for fine-tuning sizes."
-        "\nThis one only applies to the 'exterior' shell of the object");
+        "\nThis one only applies to the 'exterior' shell of the object."
+        "\n !!! it's recommended you put the same value into the 'Inner XY size compensation', unless you are sure you don't have horizontal holes. !!! ");
     def->sidetext = L("mm");
     def->mode = comExpert;
     def->set_default_value(new ConfigOptionFloat(0));
@@ -3736,7 +3737,7 @@ void PrintConfigDef::init_fff_params()
     def->category = OptionCategory::slicing;
     def->tooltip = L("The object will be grown/shrunk in the XY plane by the configured value "
         "(negative = inwards, positive = outwards). This might be useful for fine-tuning sizes."
-        "\nThis one only applies to the 'inner' shell of the object");
+        "\nThis one only applies to the 'inner' shell of the object (!!! horizontal holes break the shell !!!)");
     def->sidetext = L("mm");
     def->mode = comExpert;
     def->set_default_value(new ConfigOptionFloat(0));
@@ -3753,6 +3754,17 @@ void PrintConfigDef::init_fff_params()
     def->mode = comExpert;
     def->set_default_value(new ConfigOptionFloat(0));
 
+    def = this->add("hole_size_threshold", coFloat);
+    def->label = L("Holes");
+    def->full_label = L("XY holes threshold");
+    def->category = OptionCategory::slicing;
+    def->tooltip = L("Maximum area for the hole where the hole_size_compensation will apply fully."
+            " After that, it will decraese down to 0 for four time this area."
+            " Set to 0 to let the hole_size_compensation apply fully for all detected holes");
+    def->sidetext = L("mm²");
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionFloat(100));
+
     def = this->add("hole_to_polyhole", coBool);
     def->label = L("Convert round holes to polyholes");
     def->full_label = L("Convert round holes to polyholes");

src/libslic3r/PrintConfig.hpp

@@ -530,6 +530,7 @@ public:
     ConfigOptionFloatOrPercent      first_layer_height;
     ConfigOptionFloat               first_layer_size_compensation;
     ConfigOptionFloat               hole_size_compensation;
+    ConfigOptionFloat               hole_size_threshold;
     ConfigOptionBool                infill_only_where_needed;
     // Force the generation of solid shells between adjacent materials/volumes.
     ConfigOptionBool                interface_shells;
@@ -592,6 +593,7 @@ protected:
         OPT_PTR(exact_last_layer_height);
         OPT_PTR(extrusion_width);
         OPT_PTR(hole_size_compensation);
+        OPT_PTR(hole_size_threshold);
         OPT_PTR(first_layer_height);
         OPT_PTR(first_layer_size_compensation);
         OPT_PTR(infill_only_where_needed);

src/libslic3r/PrintObject.cpp

@@ -646,6 +646,7 @@ bool PrintObject::invalidate_state_by_config_options(const std::vector<t_config_
             || opt_key == "support_material_contact_distance_bottom" 
             || opt_key == "xy_size_compensation"
             || opt_key == "hole_size_compensation"
+            || opt_key == "hole_size_threshold"
             || opt_key == "hole_to_polyhole"
             || opt_key == "z_step") {
             steps.emplace_back(posSlice);
@@ -2520,6 +2521,7 @@ end:
 
 ExPolygons PrintObject::_shrink_contour_holes(double contour_delta, double default_delta, double convex_delta, const ExPolygons& polys) const {
     ExPolygons new_ex_polys;
+    double max_hole_area = scale_d(scale_d(m_config.hole_size_threshold.value));
     for (const ExPolygon& ex_poly : polys) {
         Polygons contours;
         Polygons holes;
@@ -2538,12 +2540,26 @@ ExPolygons PrintObject::_shrink_contour_holes(double contour_delta, double defau
 
             // check whether last point forms a convex angle
             ok &= (hole.points.back().ccw_angle(*(hole.points.end() - 2), hole.points.front()) <= PI + 0.1);
-
+             
             if (ok) {
                 if (convex_delta != 0) {
-                    for (Polygon &newHole : offset(hole, -convex_delta)) {
-                        newHole.make_counter_clockwise();
-                        holes.emplace_back(std::move(newHole));
+                    //apply hole threshold cutoff
+                    double convex_delta_adapted = convex_delta;
+                    double area = -hole.area();
+                    if (area > max_hole_area * 4) {
+                        convex_delta_adapted = 0;
+                    }else if (area > max_hole_area) {
+                        // not a hard threshold, to avoid artefacts on slopped holes.
+                        convex_delta_adapted = convex_delta * (max_hole_area * 4 - area) / (max_hole_area * 3);
+                    }
+                    if (convex_delta_adapted != 0) {
+                        for (Polygon &newHole : offset(hole, -convex_delta_adapted)) {
+                            newHole.make_counter_clockwise();
+                            holes.emplace_back(std::move(newHole));
+                        }
+                    } else {
+                        holes.push_back(hole);
+                        holes.back().make_counter_clockwise();
                     }
                 } else {
                     holes.push_back(hole);

src/libslic3r/libslic3r.h

@@ -100,6 +100,8 @@ inline T unscale(Q v) { return T(v) * T(SCALING_FACTOR); }
 inline double unscaled(double v) { return v * SCALING_FACTOR; }
 inline coordf_t unscale_(coord_t v) { return v * SCALING_FACTOR; }
 inline coord_t scale_t(coordf_t v) { return (coord_t)(v / SCALING_FACTOR); }
+inline double scale_d(coordf_t v) { return (v / SCALING_FACTOR); }
+inline double scale_d(coord_t v) { return ((double)v / SCALING_FACTOR); }
 
 enum Axis { 
 	X=0,

src/slic3r/GUI/Preset.cpp

@@ -519,7 +519,8 @@ const std::vector<std::string>& Preset::print_options()
         "first_layer_size_compensation",
         "xy_size_compensation",
         "xy_inner_size_compensation",
-        "hole_size_compensation", 
+        "hole_size_compensation",
+        "hole_size_threshold",
         "hole_to_polyhole",
         "threads", "resolution",
         "wipe_tower", "wipe_tower_x", "wipe_tower_y", "wipe_tower_width", "wipe_tower_rotation_angle", "wipe_tower_bridging",