Promote max_bridges_on_pillar to be a runtime parameter.

This way the user greater control over support tree branching and the amount of pillars created.

src/libslic3r/PrintConfig.cpp

@@ -2653,6 +2653,16 @@ void PrintConfigDef::init_sla_params()
     def->max = 15;
     def->mode = comSimple;
     def->set_default_value(new ConfigOptionFloat(1.0));
+    
+    def = this->add("support_max_bridges_on_pillar", coInt);
+    def->label = L("Max bridges on a pillar");
+    def->tooltip = L(
+        "Maximum number of bridges that can be placed on a pillar. Bridges "
+        "hold support point pinheads and connect to pillars as small branches.");
+    def->min = 0;
+    def->max = 50;
+    def->mode = comExpert;
+    def->set_default_value(new ConfigOptionInt(3));
 
     def = this->add("support_pillar_connection_mode", coEnum);
     def->label = L("Support pillar connection mode");

src/libslic3r/PrintConfig.hpp

@@ -980,6 +980,9 @@ public:
 
     // Radius in mm of the support pillars.
     ConfigOptionFloat support_pillar_diameter /*= 0.8*/;
+    
+    // How much bridge (supporting another pinhead) can be placed on a pillar.
+    ConfigOptionInt   support_max_bridges_on_pillar;
 
     // How the pillars are bridged together
     ConfigOptionEnum<SLAPillarConnectionMode> support_pillar_connection_mode;
@@ -1101,6 +1104,7 @@ protected:
         OPT_PTR(support_head_penetration);
         OPT_PTR(support_head_width);
         OPT_PTR(support_pillar_diameter);
+        OPT_PTR(support_max_bridges_on_pillar);
         OPT_PTR(support_pillar_connection_mode);
         OPT_PTR(support_buildplate_only);
         OPT_PTR(support_pillar_widening_factor);

src/libslic3r/SLA/SupportTree.cpp

@@ -41,7 +41,6 @@ const double SupportConfig::max_dual_pillar_height_mm = 35.0;
 const double   SupportConfig::optimizer_rel_score_diff = 1e-6;
 const unsigned SupportConfig::optimizer_max_iterations = 1000;
 const unsigned SupportConfig::pillar_cascade_neighbors = 3;
-const unsigned SupportConfig::max_bridges_on_pillar = 3;
 
 void SupportTree::retrieve_full_mesh(TriangleMesh &outmesh) const {
     outmesh.merge(retrieve_mesh(MeshType::Support));

src/libslic3r/SLA/SupportTree.hpp

@@ -83,6 +83,8 @@ struct SupportConfig
     // body. This is only useful when elevation is set to zero.
     double pillar_base_safety_distance_mm = 0.5;
     
+    unsigned max_bridges_on_pillar = 3;
+    
     double head_fullwidth() const {
         return 2 * head_front_radius_mm + head_width_mm +
                2 * head_back_radius_mm - head_penetration_mm;
@@ -103,7 +105,7 @@ struct SupportConfig
     static const double   optimizer_rel_score_diff;
     static const unsigned optimizer_max_iterations;
     static const unsigned pillar_cascade_neighbors;
-    static const unsigned max_bridges_on_pillar;
+    
 };
 
 enum class MeshType { Support, Pad };

src/libslic3r/SLAPrint.cpp

@@ -65,6 +65,8 @@ sla::SupportConfig make_support_cfg(const SLAPrintObjectConfig& c)
         c.support_base_safety_distance.getFloat() < EPSILON ?
             scfg.safety_distance_mm : c.support_base_safety_distance.getFloat();
     
+    scfg.max_bridges_on_pillar = unsigned(c.support_max_bridges_on_pillar.getInt());
+    
     return scfg;
 }
 
@@ -946,6 +948,7 @@ bool SLAPrintObject::invalidate_state_by_config_options(const std::vector<t_conf
             || opt_key == "support_head_penetration"
             || opt_key == "support_head_width"
             || opt_key == "support_pillar_diameter"
+            || opt_key == "support_max_bridges_on_pillar"
             || opt_key == "support_pillar_connection_mode"
             || opt_key == "support_buildplate_only"
             || opt_key == "support_base_diameter"

src/slic3r/GUI/ConfigManipulation.cpp

@@ -347,6 +347,7 @@ void ConfigManipulation::toggle_print_sla_options(DynamicPrintConfig* config)
     toggle_field("support_head_penetration", supports_en);
     toggle_field("support_head_width", supports_en);
     toggle_field("support_pillar_diameter", supports_en);
+    toggle_field("support_max_bridges_on_pillar", supports_en);
     toggle_field("support_pillar_connection_mode", supports_en);
     toggle_field("support_buildplate_only", supports_en);
     toggle_field("support_base_diameter", supports_en);

src/slic3r/GUI/Preset.cpp

@@ -480,6 +480,7 @@ const std::vector<std::string>& Preset::sla_print_options()
             "support_head_penetration",
             "support_head_width",
             "support_pillar_diameter",
+            "support_max_bridges_on_pillar",
             "support_pillar_connection_mode",
             "support_buildplate_only",
             "support_pillar_widening_factor",

src/slic3r/GUI/Tab.cpp

@@ -3612,6 +3612,8 @@ void TabSLAPrint::build()
 
     optgroup = page->new_optgroup(_(L("Support pillar")));
     optgroup->append_single_option_line("support_pillar_diameter");
+    optgroup->append_single_option_line("support_max_bridges_on_pillar");
+    
     optgroup->append_single_option_line("support_pillar_connection_mode");
     optgroup->append_single_option_line("support_buildplate_only");
     // TODO: This parameter is not used at the moment.