Enhancement: Do not slow down external perimeters to meet minimum layer time

src/libslic3r/GCode/CoolingBuffer.cpp

@@ -222,6 +222,9 @@ struct PerExtruderAdjustments
     float                       slow_down_layer_time = 0.f;
     // Minimum print speed allowed for this extruder.
     float                       slow_down_min_speed     = 0.f;
+
+    bool                        dont_slow_down_external_perimeters = false;
+
 
     // Parsed lines.
     std::vector<CoolingLine>    lines;
@@ -330,6 +333,8 @@ std::vector<PerExtruderAdjustments> CoolingBuffer::parse_layer_gcode(const std::
         adj.cooling_slow_down_enabled = m_config.slow_down_for_layer_cooling.get_at(extruder_id);
         adj.slow_down_layer_time = float(m_config.slow_down_layer_time.get_at(extruder_id));
         adj.slow_down_min_speed           = float(m_config.slow_down_min_speed.get_at(extruder_id));
+        // ORCA: To enable dont slow down external perimeters feature per filament (extruder)
+        adj.dont_slow_down_external_perimeters   = m_config.dont_slow_down_external_perimeters.get_at(extruder_id);
         map_extruder_to_per_extruder_adjustment[extruder_id] = i;
     }
 
@@ -399,7 +404,15 @@ std::vector<PerExtruderAdjustments> CoolingBuffer::parse_layer_gcode(const std::
                 line.type |= CoolingLine::TYPE_EXTERNAL_PERIMETER;
             if (wipe)
                 line.type |= CoolingLine::TYPE_WIPE;
-            if (boost::contains(sline, ";_EXTRUDE_SET_SPEED") && ! wipe) {
+
+            // ORCA: Dont slowdown external perimeters for layer time feature
+            // use the adjustment pointer to ensure the value for the current extruder (filament) is used.
+            bool adjust_external = true;
+            if(adjustment->dont_slow_down_external_perimeters && external_perimeter) adjust_external = false;
+
+            // ORCA: Dont slowdown external perimeters for layer time works by not marking the external perimeter as adjustable, 
+            // hence the slowdown algorithm ignores it.
+            if (boost::contains(sline, ";_EXTRUDE_SET_SPEED") && ! wipe && adjust_external) {
                 line.type |= CoolingLine::TYPE_ADJUSTABLE;
                 active_speed_modifier = adjustment->lines.size();
             }

src/libslic3r/Preset.cpp

@@ -825,7 +825,7 @@ static std::vector<std::string> s_Preset_filament_options {
     "cool_plate_temp", "eng_plate_temp", "hot_plate_temp", "textured_plate_temp", "cool_plate_temp_initial_layer", "eng_plate_temp_initial_layer", "hot_plate_temp_initial_layer","textured_plate_temp_initial_layer",
     // "bed_type",
     //BBS:temperature_vitrification
-    "temperature_vitrification", "reduce_fan_stop_start_freq", "slow_down_for_layer_cooling", "fan_min_speed",
+    "temperature_vitrification", "reduce_fan_stop_start_freq","dont_slow_down_external_perimeters", "slow_down_for_layer_cooling", "fan_min_speed",
     "fan_max_speed", "enable_overhang_bridge_fan", "overhang_fan_speed", "overhang_fan_threshold", "close_fan_the_first_x_layers", "full_fan_speed_layer", "fan_cooling_layer_time", "slow_down_layer_time", "slow_down_min_speed",
     "filament_start_gcode", "filament_end_gcode",
     //exhaust fan control

src/libslic3r/Print.cpp

@@ -109,6 +109,7 @@ bool Print::invalidate_state_by_config_options(const ConfigOptionResolver & /* n
         "extruder_offset",
         "filament_flow_ratio",
         "reduce_fan_stop_start_freq",
+        "dont_slow_down_external_perimeters",
         "fan_cooling_layer_time",
         "full_fan_speed_layer",
         "fan_kickstart",

src/libslic3r/PrintConfig.cpp

@@ -1700,6 +1700,15 @@ void PrintConfigDef::init_fff_params()
     def->tooltip = L("If enable this setting, part cooling fan will never be stoped and will run at least "
                      "at minimum speed to reduce the frequency of starting and stoping");
     def->set_default_value(new ConfigOptionBools { false });
+
+    def = this->add("dont_slow_down_external_perimeters", coBools);
+    def->label = L("Don't slow down external perimeters to meet minimum layer time");
+    def->tooltip = L("If enabled, this setting will ensure external perimeters are not slowed down to meet the minimum layer time. "
+                     "This is particularly helpful in the below scenarios:\n\n "
+                     "1. To avoid changes in shine when printing glossy filaments \n"
+                     "2. To avoid changes in external wall speed which may create slight wall artefacts that appear like z banding \n"
+                     "3. To avoid printing at speeds which cause VFAs (fine artefacts) on the external walls\n\n");
+    def->set_default_value(new ConfigOptionBools { false });
 
     def = this->add("fan_cooling_layer_time", coFloats);
     def->label = L("Layer time");

src/libslic3r/PrintConfig.hpp

@@ -1174,6 +1174,7 @@ PRINT_CONFIG_CLASS_DERIVED_DEFINE(
     ((ConfigOptionStrings,            extruder_colour))
     ((ConfigOptionPoints,             extruder_offset))
     ((ConfigOptionBools,              reduce_fan_stop_start_freq))
+    ((ConfigOptionBools,              dont_slow_down_external_perimeters))
     ((ConfigOptionFloats,             fan_cooling_layer_time))
     ((ConfigOptionStrings,            filament_colour))
     ((ConfigOptionBools,              activate_air_filtration))

src/slic3r/GUI/Tab.cpp

@@ -3330,6 +3330,7 @@ void TabFilament::build()
         optgroup->append_line(line);
         optgroup->append_single_option_line("reduce_fan_stop_start_freq");
         optgroup->append_single_option_line("slow_down_for_layer_cooling", "auto-cooling");
+        optgroup->append_single_option_line("dont_slow_down_external_perimeters");
         optgroup->append_single_option_line("slow_down_min_speed");
 
         optgroup->append_single_option_line("enable_overhang_bridge_fan", "auto-cooling");
@@ -3504,6 +3505,10 @@ void TabFilament::toggle_options()
             toggle_option(el, has_enable_overhang_bridge_fan);
 
       toggle_option("additional_cooling_fan_speed", cfg.opt_bool("auxiliary_fan"));
+
+      // Orca: toggle dont slow down for external perimeters if
+      bool has_slow_down_for_layer_cooling = m_config->opt_bool("slow_down_for_layer_cooling", 0);
+      toggle_option("dont_slow_down_external_perimeters", has_slow_down_for_layer_cooling);
     }
     if (m_active_page->title() == L("Filament"))
     {