FDM snug supports: New parameter "closing radius", inspired by Cura's

support_join_distance

src/libslic3r/Config.hpp

@@ -1967,8 +1967,9 @@ public:
     int                 opt_int(const t_config_option_key &opt_key, unsigned int idx) const     { return dynamic_cast<const ConfigOptionInts*>(this->option(opt_key))->get_at(idx); }
 
     // In ConfigManipulation::toggle_print_fff_options, it is called on option with type ConfigOptionEnumGeneric* and also ConfigOptionEnum*.
+    // Thus the virtual method getInt() is used to retrieve the enum value.
     template<typename ENUM>
-    ENUM                opt_enum(const t_config_option_key &opt_key) const                      { return this->option<ConfigOptionEnum<ENUM>>(opt_key)->value; }
+    ENUM                opt_enum(const t_config_option_key &opt_key) const                      { return static_cast<ENUM>(this->option(opt_key)->getInt()); }
 
     bool                opt_bool(const t_config_option_key &opt_key) const                      { return this->option<ConfigOptionBool>(opt_key)->value != 0; }
     bool                opt_bool(const t_config_option_key &opt_key, unsigned int idx) const    { return this->option<ConfigOptionBools>(opt_key)->get_at(idx) != 0; }

src/libslic3r/Preset.cpp

@@ -427,7 +427,7 @@ const std::vector<std::string>& Preset::print_options()
         "bridge_acceleration", "first_layer_acceleration", "default_acceleration", "skirts", "skirt_distance", "skirt_height", "draft_shield",
         "min_skirt_length", "brim_width", "brim_offset", "brim_type", "support_material", "support_material_auto", "support_material_threshold", "support_material_enforce_layers",
         "raft_layers", "raft_first_layer_density", "raft_first_layer_expansion", "raft_contact_distance", "raft_expansion",
-        "support_material_pattern", "support_material_with_sheath", "support_material_spacing", "support_material_style",
+        "support_material_pattern", "support_material_with_sheath", "support_material_spacing", "support_material_closing_radius", "support_material_style",
         "support_material_synchronize_layers", "support_material_angle", "support_material_interface_layers", "support_material_bottom_interface_layers",
         "support_material_interface_pattern", "support_material_interface_spacing", "support_material_interface_contact_loops", 
         "support_material_contact_distance", "support_material_bottom_contact_distance",

src/libslic3r/PrintConfig.cpp

@@ -2366,6 +2366,16 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionInt(-1));
 
+    def = this->add("support_material_closing_radius", coFloat);
+    def->label = L("Closing radius");
+    def->category = L("Support material");
+    def->tooltip = L("For snug supports, the support regions will be merged using morphological closing operation."
+                     " Gaps smaller than the closing radius will be filled in.");
+    def->sidetext = L("mm");
+    def->min = 0;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(2));
+
     def = this->add("support_material_interface_spacing", coFloat);
     def->label = L("Interface pattern spacing");
     def->category = L("Support material");

src/libslic3r/PrintConfig.hpp

@@ -530,6 +530,8 @@ public:
     ConfigOptionFloatOrPercent      support_material_interface_speed;
     ConfigOptionEnum<SupportMaterialPattern> support_material_pattern;
     ConfigOptionEnum<SupportMaterialInterfacePattern> support_material_interface_pattern;
+    // Morphological closing of support areas. Only used for "sung" supports.
+    ConfigOptionFloat               support_material_closing_radius;
     // Spacing between support material lines (the hatching distance).
     ConfigOptionFloat               support_material_spacing;
     ConfigOptionFloat               support_material_speed;
@@ -579,6 +581,7 @@ protected:
         OPT_PTR(support_material_interface_extruder);
         OPT_PTR(support_material_interface_layers);
         OPT_PTR(support_material_bottom_interface_layers);
+        OPT_PTR(support_material_closing_radius);
         OPT_PTR(support_material_interface_spacing);
         OPT_PTR(support_material_interface_speed);
         OPT_PTR(support_material_pattern);

src/libslic3r/PrintObject.cpp

@@ -591,6 +591,7 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "support_material_style"
             || opt_key == "support_material_xy_spacing"
             || opt_key == "support_material_spacing"
+            || opt_key == "support_material_closing_radius"
             || opt_key == "support_material_synchronize_layers"
             || opt_key == "support_material_threshold"
             || opt_key == "support_material_with_sheath"

src/libslic3r/SupportMaterial.cpp

@@ -672,6 +672,7 @@ struct SupportGridParams {
         grid_resolution(object_config.support_material_spacing.value + support_material_flow.spacing()),
         support_angle(Geometry::deg2rad(object_config.support_material_angle.value)),
         extrusion_width(support_material_flow.spacing()),
+        support_material_closing_radius(object_config.support_material_closing_radius.value),
         expansion_to_slice(coord_t(support_material_flow.scaled_spacing() / 2 + 5)),
         expansion_to_propagate(-3) {}
 
@@ -679,6 +680,7 @@ struct SupportGridParams {
     double                  grid_resolution;
     double                  support_angle;
     double                  extrusion_width;
+    double                  support_material_closing_radius;
     coord_t                 expansion_to_slice;
     coord_t                 expansion_to_propagate;
 };
@@ -694,7 +696,9 @@ public:
         const SupportGridParams &params) :
         m_style(params.style),
         m_support_polygons(support_polygons), m_trimming_polygons(trimming_polygons),
-        m_support_spacing(params.grid_resolution), m_support_angle(params.support_angle)
+        m_support_spacing(params.grid_resolution), m_support_angle(params.support_angle),
+        m_extrusion_width(params.extrusion_width),
+        m_support_material_closing_radius(params.support_material_closing_radius)
     {
         switch (m_style) {
         case smsGrid:
@@ -878,9 +882,10 @@ public:
             return out;
         }
         case smsSnug:
-            // Just close the gaps.
+            // Merge the support polygons by applying morphological closing and inwards smoothing.
-            float thr = scaled<float>(0.5);
+            auto closing_distance   = scaled<float>(m_support_material_closing_radius);
-            return smooth_outward(offset(offset_ex(*m_support_polygons, thr), - thr), thr);
+            auto smoothing_distance = scaled<float>(m_extrusion_width);
+            return smooth_outward(offset(offset_ex(*m_support_polygons, closing_distance), - closing_distance), smoothing_distance);
         }
         assert(false);
         return Polygons();
@@ -1128,6 +1133,9 @@ private:
     coordf_t                m_support_angle;
     // X spacing of the support lines parallel with the Y axis.
     coordf_t                m_support_spacing;
+    coordf_t                m_extrusion_width;
+    // For snug supports: Morphological closing of support areas.
+    coordf_t                m_support_material_closing_radius;
 
 #ifdef SUPPORT_USE_AGG_RASTERIZER
     Vec2i                       m_grid_size;

src/slic3r/GUI/ConfigManipulation.cpp

@@ -278,6 +278,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig* config)
     bool have_support_material_auto = have_support_material && config->opt_bool("support_material_auto");
     bool have_support_interface = config->opt_int("support_material_interface_layers") > 0;
     bool have_support_soluble = have_support_material && config->opt_float("support_material_contact_distance") == 0;
+    auto support_material_style = config->opt_enum<SupportMaterialStyle>("support_material_style");
     for (auto el : { "support_material_style", "support_material_pattern", "support_material_with_sheath",
                     "support_material_spacing", "support_material_angle", 
                     "support_material_interface_pattern", "support_material_interface_layers",
@@ -286,6 +287,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig* config)
         toggle_field(el, have_support_material);
     toggle_field("support_material_threshold", have_support_material_auto);
     toggle_field("support_material_bottom_contact_distance", have_support_material && ! have_support_soluble);
+    toggle_field("support_material_closing_radius", have_support_material && support_material_style == smsSnug);
 
     for (auto el : { "support_material_bottom_interface_layers", "support_material_interface_spacing", "support_material_interface_extruder",
                     "support_material_interface_speed", "support_material_interface_contact_loops" })

src/slic3r/GUI/Tab.cpp

@@ -1515,6 +1515,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("support_material_with_sheath", category_path + "with-sheath-around-the-support");
         optgroup->append_single_option_line("support_material_spacing", category_path + "pattern-spacing-0-inf");
         optgroup->append_single_option_line("support_material_angle", category_path + "pattern-angle");
+        optgroup->append_single_option_line("support_material_closing_radius", category_path + "pattern-angle");
         optgroup->append_single_option_line("support_material_interface_layers", category_path + "interface-layers");
         optgroup->append_single_option_line("support_material_bottom_interface_layers", category_path + "interface-layers");
         optgroup->append_single_option_line("support_material_interface_pattern", category_path + "interface-pattern");