ENH: add bridge_bottom_surface_pattern process setting

resources/profiles/BBL/process/fdm_process_common.json

@@ -8,6 +8,7 @@
     "bottom_color_penetration_layers": "3",
     "bottom_shell_thickness": "0",
     "bottom_surface_pattern": "monotonic",
+    "bridge_bottom_surface_pattern": "default",
     "bottom_surface_density": "100",
     "bridge_flow": "0.95",
     "bridge_no_support": "0",

src/libslic3r/Fill/Fill.cpp

@@ -20,6 +20,22 @@
 
 namespace Slic3r {
 
+static InfillPattern infill_for_bridge_bottom(BridgeBottomSurfacePattern pattern, InfillPattern top_surface_pattern)
+{
+    switch (pattern) {
+    case bbspDefault:            return top_surface_pattern == ipMonotonic ? ipMonotonic : ipRectilinear;
+    case bbspConcentric:         return ipConcentric;
+    case bbspRectilinear:        return ipRectilinear;
+    case bbspMonotonic:          return ipMonotonic;
+    case bbspMonotonicLine:      return ipMonotonicLine;
+    case bbspAlignedRectilinear: return ipAlignedRectilinear;
+    case bbspHilbertCurve:       return ipHilbertCurve;
+    case bbspArchimedeanChords:  return ipArchimedeanChords;
+    case bbspOctagramSpiral:     return ipOctagramSpiral;
+    }
+    return ipRectilinear;
+}
+
 struct SurfaceFillParams
 {
 	// Zero based extruder ID.
@@ -228,14 +244,16 @@ std::vector<SurfaceFill> group_fills(const Layer &layer, LockRegionParam &lock_p
 
 				if (surface.is_solid()) {
 		            params.density = 100.f;
-					//FIXME for non-thick bridges, shall we allow a bottom surface pattern?
 					if (surface.is_floating_vertical_shell())
 						params.pattern = InfillPattern::ipFloatingConcentric;
 					else if (surface.is_solid_infill())
                         params.pattern = region_config.internal_solid_infill_pattern.value;
                     else if (surface.is_external() && !is_bridge) {
                         params.pattern = surface.is_top() ? region_config.top_surface_pattern.value : region_config.bottom_surface_pattern.value;
                         params.density = surface.is_top() ? region_config.top_surface_density.value : region_config.bottom_surface_density.value;
+                    } else if (is_bridge && surface.is_bottom()) {
+                        params.pattern = infill_for_bridge_bottom(region_config.bridge_bottom_surface_pattern.value,
+                                                                  region_config.top_surface_pattern.value);
                     } else
 						params.pattern = region_config.top_surface_pattern == ipMonotonic ? ipMonotonic : ipRectilinear;
                     if (params.pattern == ipMonotonicLine) params.monotonic_travel_into_wall = region_config.monotonic_travel_into_wall.value;

src/libslic3r/Preset.cpp

@@ -1018,7 +1018,7 @@ static std::vector<std::string> s_Preset_print_options {
     "smooth_speed_discontinuity_area","smooth_coefficient", "seam_position", "seam_placement_away_from_overhangs", "wall_sequence", "is_infill_first", "sparse_infill_density", "fill_multiline",
     "sparse_infill_pattern", "sparse_infill_anchor", "sparse_infill_anchor_max", "top_surface_pattern", "monotonic_travel_into_wall",
     "locked_skin_infill_pattern", "locked_skeleton_infill_pattern",
-    "bottom_surface_pattern", "internal_solid_infill_pattern", "infill_direction", "bridge_angle", "infill_shift_step", "skeleton_infill_density", "infill_lock_depth", "skin_infill_depth", "skin_infill_density",
+    "bottom_surface_pattern", "bridge_bottom_surface_pattern", "internal_solid_infill_pattern", "infill_direction", "bridge_angle", "infill_shift_step", "skeleton_infill_density", "infill_lock_depth", "skin_infill_depth", "skin_infill_density",
     "infill_rotate_step","top_surface_density", "bottom_surface_density",
     "symmetric_infill_y_axis","sparse_infill_lattice_angle_1","sparse_infill_lattice_angle_2",
     "minimum_sparse_infill_area", "reduce_infill_retraction_mode", "ironing_pattern", "ironing_type",

src/libslic3r/PrintConfig.cpp

@@ -244,6 +244,19 @@ static t_config_enum_values s_keys_map_InfillPattern {
 };
 CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(InfillPattern)
 
+static t_config_enum_values s_keys_map_BridgeBottomSurfacePattern {
+    { "default",            bbspDefault },
+    { "concentric",         bbspConcentric },
+    { "zig-zag",            bbspRectilinear },
+    { "monotonic",          bbspMonotonic },
+    { "monotonicline",      bbspMonotonicLine },
+    { "alignedrectilinear", bbspAlignedRectilinear },
+    { "hilbertcurve",       bbspHilbertCurve },
+    { "archimedeanchords",  bbspArchimedeanChords },
+    { "octagramspiral",     bbspOctagramSpiral },
+};
+CONFIG_OPTION_ENUM_DEFINE_STATIC_MAPS(BridgeBottomSurfacePattern)
+
 static t_config_enum_values s_keys_map_IroningType {
     { "no ironing",     int(IroningType::NoIroning) },
     { "top",            int(IroningType::TopSurfaces) },
@@ -2125,6 +2138,19 @@ void PrintConfigDef::init_fff_params()
     def->enum_labels = def_top_fill_pattern->enum_labels;
     def->set_default_value(new ConfigOptionEnum<InfillPattern>(ipRectilinear));
 
+    def = this->add("bridge_bottom_surface_pattern", coEnum);
+    def->label = L("Bridge bottom surface pattern");
+    def->category = L("Strength");
+    def->tooltip = L("Line pattern for the underside of bridges (overhangs printed over support or air). "
+                     "Default uses monotonic if the top surface is monotonic, otherwise rectilinear.");
+    def->enum_keys_map = &ConfigOptionEnum<BridgeBottomSurfacePattern>::get_enum_values();
+    def->enum_values.push_back("default");
+    def->enum_values.insert(def->enum_values.end(), def_top_fill_pattern->enum_values.begin(), def_top_fill_pattern->enum_values.end());
+    def->enum_labels.push_back(L("Default"));
+    def->enum_labels.insert(def->enum_labels.end(), def_top_fill_pattern->enum_labels.begin(), def_top_fill_pattern->enum_labels.end());
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionEnum<BridgeBottomSurfacePattern>(bbspDefault));
+
     def           = this->add("bottom_surface_density", coPercent);
     def->label    = L("Bottom surface density");
     def->category = L("Strength");
@@ -9519,6 +9545,10 @@ std::map<std::string, std::string> validate(const FullPrintConfig &cfg, bool und
         error_message.emplace("bottom_surface_pattern", L("invalid value ") + cfg.bottom_surface_pattern.serialize());
     }
 
+    if (!print_config_def.get("bridge_bottom_surface_pattern")->has_enum_value(cfg.bridge_bottom_surface_pattern.serialize())) {
+        error_message.emplace("bridge_bottom_surface_pattern", L("invalid value ") + cfg.bridge_bottom_surface_pattern.serialize());
+    }
+
     // --soild-fill-pattern
     if (!print_config_def.get("internal_solid_infill_pattern")->has_enum_value(cfg.internal_solid_infill_pattern.serialize())) {
         error_message.emplace("internal_solid_infill_pattern", L("invalid value ") + cfg.internal_solid_infill_pattern.serialize());

src/libslic3r/PrintConfig.hpp

@@ -91,6 +91,19 @@ enum InfillPattern : int {
     ipCount,
 };
 
+// Pattern choices for bridge_bottom_surface_pattern. Default is setting behaviour, not a fill algorithm.
+enum BridgeBottomSurfacePattern {
+    bbspDefault,
+    bbspConcentric,
+    bbspRectilinear,
+    bbspMonotonic,
+    bbspMonotonicLine,
+    bbspAlignedRectilinear,
+    bbspHilbertCurve,
+    bbspArchimedeanChords,
+    bbspOctagramSpiral,
+};
+
 enum EnsureVerticalThicknessLevel{
     evtDisabled,
     evtPartial,
@@ -1072,6 +1085,7 @@ PRINT_CONFIG_CLASS_DEFINE(
     ((ConfigOptionEnum<EnsureVerticalThicknessLevel>, ensure_vertical_shell_thickness))
     ((ConfigOptionEnum<InfillPattern>, top_surface_pattern))
     ((ConfigOptionEnum<InfillPattern>, bottom_surface_pattern))
+    ((ConfigOptionEnum<BridgeBottomSurfacePattern>, bridge_bottom_surface_pattern))
     ((ConfigOptionPercent, monotonic_travel_into_wall))
     ((ConfigOptionPercent, top_surface_density))
     ((ConfigOptionPercent, bottom_surface_density))

src/libslic3r/PrintObject.cpp

@@ -1256,6 +1256,7 @@ bool PrintObject::invalidate_state_by_config_options(
             || opt_key == "top_surface_density"
             || opt_key == "monotonic_travel_into_wall"
             || opt_key == "bottom_surface_pattern"
+            || opt_key == "bridge_bottom_surface_pattern"
             || opt_key == "bottom_surface_density"
             || opt_key == "internal_solid_infill_pattern"
             || opt_key == "external_fill_link_max_length"

src/slic3r/GUI/ConfigManipulation.cpp

@@ -911,7 +911,7 @@ void ConfigManipulation::toggle_print_fff_options(DynamicPrintConfig *config, in
     bool has_bottom_solid_infill = config->opt_int("bottom_shell_layers") > 0;
     bool has_solid_infill 		 = has_top_solid_infill || has_bottom_solid_infill;
     // solid_infill_filament uses the same logic as in Print::extruders()
-    for (auto el : {"top_surface_pattern", "bottom_surface_pattern", "top_surface_density", "bottom_surface_density", "internal_solid_infill_pattern", "solid_infill_filament"})
+    for (auto el : {"top_surface_pattern", "bottom_surface_pattern", "bridge_bottom_surface_pattern", "top_surface_density", "bottom_surface_density", "internal_solid_infill_pattern", "solid_infill_filament"})
         toggle_field(el, has_solid_infill);
 
     for (auto el : { "infill_direction", "sparse_infill_line_width", "bridge_angle",

src/slic3r/GUI/GUI_Factories.cpp

@@ -105,7 +105,7 @@ std::map<std::string, std::vector<SimpleSettingData>>  SettingsFactory::PART_CAT
                     {"bottom_shell_layers", "",1}, {"bottom_shell_thickness", "",1}, {"sparse_infill_density", "",1},
                     {"sparse_infill_pattern", "",1},{"sparse_infill_anchor", "",1},{"sparse_infill_anchor_max", "",1}, {"sparse_infill_lattice_angle_1", "",1},{"sparse_infill_lattice_angle_2", "",1},
                     {"top_surface_pattern", "",1},{"top_surface_density", "",1},{"monotonic_travel_into_wall", "",1},
-                    {"bottom_surface_pattern", "",1}, {"bottom_surface_density", "",1}, {"internal_solid_infill_pattern", "",1},
+                    {"bottom_surface_pattern", "",1}, {"bottom_surface_density", "",1}, {"bridge_bottom_surface_pattern", "",1}, {"internal_solid_infill_pattern", "",1},
                     {"infill_combination", "",1}, {"infill_wall_overlap", "",1}, {"infill_direction", "",1}, {"bridge_angle", "",1},{"minimum_sparse_infill_area", "",1}
                     }},
     { L("Speed"), {{"outer_wall_speed", "",1},{"inner_wall_speed", "",2},{"sparse_infill_speed", "",3},{"top_surface_speed", "",4}, {"internal_solid_infill_speed", "",5},

src/slic3r/GUI/Tab.cpp

@@ -3301,6 +3301,7 @@ void TabPrint::build()
         optgroup->append_single_option_line("bottom_shell_thickness");
         optgroup->append_single_option_line("bottom_color_penetration_layers");
         optgroup->append_single_option_line("infill_instead_top_bottom_surfaces");
+        optgroup->append_single_option_line("bridge_bottom_surface_pattern");
         optgroup->append_single_option_line("internal_solid_infill_pattern");
 
         optgroup = page->new_optgroup(L("Sparse infill"), L"param_infill");