feat(perimeters): Reverse extrusion on odd layers

Add options to reverse the extrusion directio for overhang perimeters, internal perimeters and infill on odd layers.
These options help to improve steep overhangs and can help reduce internal stress and warping in large parts.

Ported from OrcaSlicer (Noisyfox @Noisyfox)

Author: mjonuschat

src/libslic3r/ExtrusionRole.hpp

@@ -1,5 +1,6 @@
 ///|/ Copyright (c) 2023 Robert Schiele @schiele
 ///|/ Copyright (c) Prusa Research 2023 Vojtěch Bubník @bubnikv
+///|/ Copyright (c) OrcaSlicer 2023 Noisyfox @Noisyfox
 ///|/
 ///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
 ///|/
@@ -86,7 +87,9 @@ struct ExtrusionRole : public ExtrusionRoleModifiers
     static constexpr const ExtrusionRoleModifiers Mixed{ ExtrusionRoleModifier::Mixed };
 
     bool is_perimeter() const { return this->ExtrusionRoleModifiers::has(ExtrusionRoleModifier::Perimeter); }
+    bool is_internal_perimeter() const { return this->is_perimeter() && !this->is_external(); }
     bool is_external_perimeter() const { return this->is_perimeter() && this->is_external(); }
+    bool is_overhang_perimeter() const { return this->is_perimeter() && this->is_bridge(); }
     bool is_infill() const { return this->ExtrusionRoleModifiers::has(ExtrusionRoleModifier::Infill); }
     bool is_solid_infill() const { return this->is_infill() && this->ExtrusionRoleModifiers::has(ExtrusionRoleModifier::Solid); }
     bool is_sparse_infill() const { return this->is_infill() && ! this->ExtrusionRoleModifiers::has(ExtrusionRoleModifier::Solid); }

src/libslic3r/GCode/ExtrusionOrder.cpp

@@ -124,10 +124,29 @@ std::vector<Perimeter> extract_perimeter_extrusions(
         for (ExtrusionEntity *ee : *eec) {
             if (ee != nullptr) {
                 std::optional<InstancePoint> last_position{get_instance_point(previous_position, offset)};
+                ExtrusionRole role = ee->role();
                 bool reverse_loop{false};
                 if (auto loop = dynamic_cast<const ExtrusionLoop *>(ee)) {
                     const bool is_hole = loop->is_clockwise();
-                    reverse_loop = print.config().prefer_clockwise_movements ? !is_hole : is_hole;
+
+                    const bool is_odd_layer = layer.id() % 2 == 1;
+                    const bool should_reverse_internal_perimeter = role.is_internal_perimeter() &&
+                        region.config().internal_perimeters_reverse;
+                    bool should_reverse_overhang_perimeters{false};
+
+                    if (region.config().overhangs_reverse && is_odd_layer) {
+                        for (const ExtrusionPath &el : loop->paths) {
+                            if (el.role().is_overhang_perimeter()) {
+                                should_reverse_overhang_perimeters = true;
+                                break;
+                            }
+                        }
+                    }
+
+                    const bool reverse_on_odd = is_odd_layer &&
+                        (should_reverse_internal_perimeter || should_reverse_overhang_perimeters);
+                    reverse_loop = (print.config().prefer_clockwise_movements ? !is_hole : is_hole) ^
+                        reverse_on_odd;
                 }
                 auto [path, wipe_offset]{smooth_path(&layer, &region, ExtrusionEntityReference{*ee, reverse_loop}, extruder_id, last_position)};
                 previous_position = get_gcode_point(last_position, offset);
@@ -190,11 +209,16 @@ std::vector<InfillRange> extract_infill_ranges(
         const std::optional<InstancePoint> previous_instance_point{get_instance_point(previous_position, offset)};
         const Point* start_near{previous_instance_point ? &(previous_instance_point->local_point) : nullptr};
         const ExtrusionEntityReferences sorted_extrusions{sort_fill_extrusions(extrusions, start_near)};
+        const bool reverse_infill = region.config().infill_reverse && layer.id() % 2 == 1;
 
         std::vector<SmoothPath> paths;
         for (const ExtrusionEntityReference &extrusion_reference : sorted_extrusions) {
             std::optional<InstancePoint> last_position{get_instance_point(previous_position, offset)};
-            auto [path, _]{smooth_path(&layer, &region, extrusion_reference, extruder_id, last_position)};
+            auto [path, _]{smooth_path(
+                &layer, &region,
+                ExtrusionEntityReference{extrusion_reference.extrusion_entity(), reverse_infill},
+                extruder_id, last_position
+            )};
             if (!path.empty()) {
                 paths.push_back(std::move(path));
             }

src/libslic3r/Preset.cpp

@@ -3,6 +3,7 @@
 ///|/ Copyright (c) 2021 Ilya @xorza
 ///|/ Copyright (c) 2019 John Drake @foxox
 ///|/ Copyright (c) 2018 Martin Loidl @LoidlM
+///|/ Copyright (c) OrcaSlicer 2023 Noisyfox @Noisyfox
 ///|/
 ///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
 ///|/
@@ -567,6 +568,10 @@ static std::vector<std::string> s_Preset_print_options {
     "wipe_tower_minimum_cruise_ratio",
 
     "alternate_extra_perimeter",
+
+    "overhangs_reverse",
+    "infill_reverse",
+    "internal_perimeters_reverse",
 };
 
 static std::vector<std::string> s_Preset_filament_options {

src/libslic3r/PrintConfig.cpp

@@ -19,6 +19,7 @@
 ///|/ Copyright (c) SuperSlicer 2019 Remi Durand @supermerill
 ///|/ Copyright (c) OrcaSlicer 2023 SoftFever @SoftFever
 ///|/ Copyright (c) 2024 Vovodroid @Vovodroid
+///|/ Copyright (c) OrcaSlicer 2023 Noisyfox @Noisyfox
 ///|/
 ///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
 ///|/
@@ -4477,6 +4478,31 @@ void PrintConfigDef::init_fff_params()
     def->min = 0;
     def->set_default_value(new ConfigOptionFloatOrPercent(85, true));
 
+    def = this->add("overhangs_reverse", coBool);
+    def->label = L("For overhang perimeters");
+    def->full_label = L("Reverse on odd layers: Overhangs");
+    def->category = L("Layers and Perimeters");
+    def->tooltip = L("Extrude perimeters that have a part over an overhang in the opposite direction on odd layers "
+                     "to improve steep overhangs.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
+    def = this->add("infill_reverse", coBool);
+    def->label = L("For infill");
+    def->full_label = L("Reverse on odd layers: Infill");
+    def->category = L("Infill");
+    def->tooltip = L("Extrude infill in the opposite direction on odd layers to reduce stress and warping.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
+    def = this->add("internal_perimeters_reverse", coBool);
+    def->label = L("For internal perimeters");
+    def->full_label = L("Reverse on odd layers: Internal Perimeters");
+    def->category = L("Layers and Perimeters");
+    def->tooltip = L("Extrude internal perimeters in the opposite direction on odd layers to reduce stress and warping.");
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionBool(false));
+
     // Declare retract values for filament profile, overriding the printer's extruder profile.
     for (const char *opt_key : {
         // floats

src/libslic3r/PrintConfig.hpp

@@ -12,6 +12,7 @@
 ///|/ Copyright (c) Slic3r 2013 - 2015 Alessandro Ranellucci @alranel
 ///|/ Copyright (c) 2015 Maksim Derbasov @ntfshard
 ///|/ Copyright (c) 2015 Alexander Rössler @machinekoder
+///|/ Copyright (c) OrcaSlicer 2023 Noisyfox @Noisyfox
 ///|/
 ///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
 ///|/
@@ -817,6 +818,10 @@ PRINT_CONFIG_CLASS_DEFINE(
 
     // SuperSlicer
     ((ConfigOptionEnum<InfillPattern>,  solid_fill_pattern))
+    // Reverse extrusion direction
+    ((ConfigOptionBool,                 overhangs_reverse))
+    ((ConfigOptionBool,                 infill_reverse))
+    ((ConfigOptionBool,                 internal_perimeters_reverse))
 )
 
 PRINT_CONFIG_CLASS_DEFINE(

src/libslic3r/PrintObject.cpp

@@ -4,6 +4,7 @@
 ///|/ Copyright (c) 2016 Joseph Lenox @lordofhyphens
 ///|/ Copyright (c) Slic3r 2014 - 2016 Alessandro Ranellucci @alranel
 ///|/ Copyright (c) 2015 Maksim Derbasov @ntfshard
+///|/ Copyright (c) OrcaSlicer 2023 Noisyfox @Noisyfox
 ///|/
 ///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
 ///|/
@@ -731,7 +732,9 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "arc_fitting"
             || opt_key == "top_one_perimeter_type"
             || opt_key == "only_one_perimeter_first_layer"
-            || opt_key == "alternate_extra_perimeter") {
+            || opt_key == "alternate_extra_perimeter"
+            || opt_key == "overhangs_reverse"
+            || opt_key == "internal_perimeters_reverse") {
             steps.emplace_back(posPerimeters);
         } else if (
                opt_key == "small_area_infill_flow_compensation"
@@ -840,7 +843,8 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "raft_first_layer_density"
             || opt_key == "raft_first_layer_expansion"
             || opt_key == "dont_support_bridges"
-            || opt_key == "first_layer_extrusion_width") {
+            || opt_key == "first_layer_extrusion_width"
+            || opt_key == "infill_reverse") {
             steps.emplace_back(posSupportMaterial);
         } else if (opt_key == "bottom_solid_layers") {
             steps.emplace_back(posPrepareInfill);

src/slic3r/GUI/ConfigManipulation.cpp

@@ -1,4 +1,5 @@
 ///|/ Copyright (c) Prusa Research 2019 - 2023 Lukáš Hejl @hejllukas, Vojtěch Bubník @bubnikv, Lukáš Matěna @lukasmatena, Oleksandra Iushchenko @YuSanka, Pavel Mikuš @Godrak, Tomáš Mészáros @tamasmeszaros
+///|/ Copyright (c) OrcaSlicer 2023 Noisyfox @Noisyfox
 ///|/
 ///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
 ///|/
@@ -140,11 +141,15 @@ void ConfigManipulation::update_print_fff_config(DynamicPrintConfig* config, con
            fill_density == 0 &&
            ! config->opt_bool("support_material") &&
            config->opt_int("support_material_enforce_layers") == 0 &&
-           ! config->opt_bool("thin_walls")))
+           ! config->opt_bool("thin_walls") &&
+           ! config->opt_bool("overhangs_reverse") &&
+           ! config->opt_bool("infill_reverse") &&
+           ! config->opt_bool("internal_perimeters_reverse")))
     {
         wxString msg_text = _(L("The Spiral Vase mode requires:\n"
                                 "- one perimeter\n"
                                 "- no extra perimeter on odd layers\n"
+                                "- no reverse on odd layers\n"
                                 "- no top solid layers\n"
                                 "- 0% fill density\n"
                                 "- no support material\n"
@@ -163,6 +168,9 @@ void ConfigManipulation::update_print_fff_config(DynamicPrintConfig* config, con
             new_conf.set_key_value("support_material", new ConfigOptionBool(false));
             new_conf.set_key_value("support_material_enforce_layers", new ConfigOptionInt(0));
             new_conf.set_key_value("thin_walls", new ConfigOptionBool(false));
+            new_conf.set_key_value("overhangs_reverse", new ConfigOptionBool(false));
+            new_conf.set_key_value("infill_reverse", new ConfigOptionBool(false));
+            new_conf.set_key_value("internal_perimeters_reverse", new ConfigOptionBool(false));
             fill_density = 0;
             support = false;
         }

src/slic3r/GUI/Tab.cpp

@@ -14,6 +14,7 @@
 ///|/ Copyright (c) 2016 Chow Loong Jin @hyperair
 ///|/ Copyright (c) 2012 QuantumConcepts
 ///|/ Copyright (c) 2012 Henrik Brix Andersen @henrikbrixandersen
+///|/ Copyright (c) OrcaSlicer 2023 Noisyfox @Noisyfox
 ///|/
 ///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
 ///|/
@@ -1837,6 +1838,12 @@ void TabPrint::build()
         optgroup->append_single_option_line("xy_size_compensation");
         optgroup->append_single_option_line("elefant_foot_compensation", "elephant-foot-compensation_114487");
 
+        line = { L("Reverse direction on odd layers"), "" };
+        line.append_option(optgroup->get_option("overhangs_reverse"));
+        line.append_option(optgroup->get_option("infill_reverse"));
+        line.append_option(optgroup->get_option("internal_perimeters_reverse"));
+        optgroup->append_line(line);
+
         optgroup = page->new_optgroup(L("Arachne perimeter generator"));
         optgroup->append_single_option_line("wall_transition_angle");
         optgroup->append_single_option_line("wall_transition_filter_deviation");