Added a threshold for purging on the wipe tower (before it goes into infill/sacrificial object)

xs/src/libslic3r/Print.cpp

@@ -205,6 +205,7 @@ bool Print::invalidate_state_by_config_options(const std::vector<t_config_option
             || opt_key == "filament_unloading_speed"
             || opt_key == "filament_toolchange_delay"
             || opt_key == "filament_cooling_moves"
+            || opt_key == "filament_minimal_purge_on_wipe_tower"
             || opt_key == "filament_cooling_initial_speed"
             || opt_key == "filament_cooling_final_speed"
             || opt_key == "filament_ramming_parameters"
@@ -1145,12 +1146,19 @@ void Print::_make_wipe_tower()
             wipe_tower.plan_toolchange(layer_tools.print_z, layer_tools.wipe_tower_layer_height, current_extruder_id, current_extruder_id,false);
             for (const auto extruder_id : layer_tools.extruders) {
                 if ((first_layer && extruder_id == m_tool_ordering.all_extruders().back()) || extruder_id != current_extruder_id) {
-                    float volume_to_wipe = wipe_volumes[current_extruder_id][extruder_id];    // total volume to wipe after this toolchange
+                    float volume_to_wipe = wipe_volumes[current_extruder_id][extruder_id];             // total volume to wipe after this toolchange
+                    // Not all of that can be used for infill purging:
+                    volume_to_wipe -= config.filament_minimal_purge_on_wipe_tower.get_at(extruder_id);
 
                     // try to assign some infills/objects for the wiping:
-                    volume_to_wipe = layer_tools.wiping_extrusions().mark_wiping_extrusions(*this, current_extruder_id, extruder_id, wipe_volumes[current_extruder_id][extruder_id]);
+                    volume_to_wipe = layer_tools.wiping_extrusions().mark_wiping_extrusions(*this, current_extruder_id, extruder_id, volume_to_wipe);
 
-                    wipe_tower.plan_toolchange(layer_tools.print_z, layer_tools.wipe_tower_layer_height, current_extruder_id, extruder_id, first_layer && extruder_id == m_tool_ordering.all_extruders().back(), volume_to_wipe);
+                    // add back the minimal amount toforce on the wipe tower:
+                    volume_to_wipe += config.filament_minimal_purge_on_wipe_tower.get_at(extruder_id);
+
+                    // request a toolchange at the wipe tower with at least volume_to_wipe purging amount
+                    wipe_tower.plan_toolchange(layer_tools.print_z, layer_tools.wipe_tower_layer_height, current_extruder_id, extruder_id,
+                                               first_layer && extruder_id == m_tool_ordering.all_extruders().back(), volume_to_wipe);
                     current_extruder_id = extruder_id;
                 }
             }

xs/src/libslic3r/PrintConfig.cpp

@@ -504,15 +504,27 @@ PrintConfigDef::PrintConfigDef()
     def = this->add("filament_cooling_initial_speed", coFloats);
     def->label = L("Speed of the first cooling move");
     def->tooltip = L("Cooling moves are gradually accelerating beginning at this speed. ");
-    def->cli = "filament-cooling-initial-speed=i@";
+    def->cli = "filament-cooling-initial-speed=f@";
     def->sidetext = L("mm/s");
     def->min = 0;
     def->default_value = new ConfigOptionFloats { 2.2f };
 
+    def = this->add("filament_minimal_purge_on_wipe_tower", coFloats);
+    def->label = L("Minimal purge on wipe tower");
+    def->tooltip = L("After a toolchange, certain amount of filament is used for purging. This "
+                     "can end up on the wipe tower, infill or sacrificial object. If there was "
+                     "enough infill etc. available, this could result in bad quality at the beginning "
+                     "of purging. This is a minimum that must be wiped on the wipe tower before "
+                     "Slic3r considers moving elsewhere. ");
+    def->cli = "filament-minimal-purge-on-wipe-tower=f@";
+    def->sidetext = L("mm³");
+    def->min = 0;
+    def->default_value = new ConfigOptionFloats { 5.f };
+
     def = this->add("filament_cooling_final_speed", coFloats);
     def->label = L("Speed of the last cooling move");
     def->tooltip = L("Cooling moves are gradually accelerating towards this speed. ");
-    def->cli = "filament-cooling-final-speed=i@";
+    def->cli = "filament-cooling-final-speed=f@";
     def->sidetext = L("mm/s");
     def->min = 0;
     def->default_value = new ConfigOptionFloats { 3.4f };

xs/src/libslic3r/PrintConfig.hpp

@@ -532,6 +532,7 @@ public:
     ConfigOptionFloats              filament_toolchange_delay;
     ConfigOptionInts                filament_cooling_moves;
     ConfigOptionFloats              filament_cooling_initial_speed;
+    ConfigOptionFloats              filament_minimal_purge_on_wipe_tower;
     ConfigOptionFloats              filament_cooling_final_speed;
     ConfigOptionStrings             filament_ramming_parameters;
     ConfigOptionBool                gcode_comments;
@@ -594,6 +595,7 @@ protected:
         OPT_PTR(filament_toolchange_delay);
         OPT_PTR(filament_cooling_moves);
         OPT_PTR(filament_cooling_initial_speed);
+        OPT_PTR(filament_minimal_purge_on_wipe_tower);
         OPT_PTR(filament_cooling_final_speed);
         OPT_PTR(filament_ramming_parameters);
         OPT_PTR(gcode_comments);

xs/src/slic3r/GUI/Preset.cpp

@@ -314,10 +314,11 @@ const std::vector<std::string>& Preset::filament_options()
     static std::vector<std::string> s_opts {
         "filament_colour", "filament_diameter", "filament_type", "filament_soluble", "filament_notes", "filament_max_volumetric_speed",
         "extrusion_multiplier", "filament_density", "filament_cost", "filament_loading_speed", "filament_unloading_speed", "filament_toolchange_delay",
-        "filament_cooling_moves", "filament_cooling_initial_speed", "filament_cooling_final_speed", "filament_ramming_parameters", "temperature",
+        "filament_cooling_moves", "filament_cooling_initial_speed", "filament_cooling_final_speed", "filament_ramming_parameters",
-        "first_layer_temperature", "bed_temperature", "first_layer_bed_temperature", "fan_always_on", "cooling", "min_fan_speed", "max_fan_speed",
+        "filament_minimal_purge_on_wipe_tower", "temperature", "first_layer_temperature", "bed_temperature", "first_layer_bed_temperature",
-        "bridge_fan_speed", "disable_fan_first_layers", "fan_below_layer_time", "slowdown_below_layer_time", "min_print_speed",
+        "fan_always_on", "cooling", "min_fan_speed", "max_fan_speed", "bridge_fan_speed", "disable_fan_first_layers", "fan_below_layer_time",
-        "start_filament_gcode", "end_filament_gcode","compatible_printers", "compatible_printers_condition", "inherits"
+        "slowdown_below_layer_time", "min_print_speed", "start_filament_gcode", "end_filament_gcode","compatible_printers", "compatible_printers_condition",
+        "inherits"
     };
     return s_opts;
 }

xs/src/slic3r/GUI/Tab.cpp

@@ -1296,6 +1296,7 @@ void TabFilament::build()
         optgroup->append_single_option_line("filament_cooling_moves");
         optgroup->append_single_option_line("filament_cooling_initial_speed");
         optgroup->append_single_option_line("filament_cooling_final_speed");
+        optgroup->append_single_option_line("filament_minimal_purge_on_wipe_tower");
 
         line = { _(L("Ramming")), "" };
         line.widget = [this](wxWindow* parent){