#280 new setting: fill_angle_increment. rotate every infill by this angle, multiplied by the layer id.

resources/ui_layout/print.ui

@@ -123,6 +123,7 @@ group:sidetext_width$3:Advanced
 	line:Angle
 		setting:label_width$6:width$5:fill_angle
 		setting:label_width$6:width$5:bridge_angle
+		setting:label_width$6:width$5:label$increment:fill_angle_increment
 	end_line
 	line:Anchor solid infill by X mm
 		setting:label_width$6:width$5:external_infill_margin

src/libslic3r/Fill/Fill.cpp

@@ -303,6 +303,7 @@ void make_fill(LayerRegion &layerm, ExtrusionEntityCollection &out)
         f->z = layerm.layer()->print_z;
         if (is_denser)f->angle = 0;
         else f->angle = float(Geometry::deg2rad(layerm.region()->config().fill_angle.value));
+        f->angle += PI * (layerm.region()->config().fill_angle_increment.value * layerm.layer()->id()) / 180.;
         // Maximum length of the perimeter segment linking two infill lines.
         f->link_max_length = (coord_t)scale_(link_max_length);
         // Used by the concentric infill pattern to clip the loops to create extrusion paths.

src/libslic3r/PrintConfig.cpp

@@ -1329,6 +1329,19 @@ void PrintConfigDef::init_fff_params()
     def->mode = comAdvanced;
     def->set_default_value(new ConfigOptionFloat(45));
 
+    def = this->add("fill_angle_increment", coFloat);
+    def->label = L("Fill");
+    def->full_label = L("Fill angle increment");
+    def->category = OptionCategory::infill;
+    def->tooltip = L("Add this angle each layer to the base angle for infill. "
+                    "May be useful for art, or to be sure to hit every object's feature even with very low infill. "
+                    "Still experiemental, tell me what makes it useful, or the problems that arise using it.");
+    def->sidetext = L("°");
+    def->min = 0;
+    def->max = 360;
+    def->mode = comAdvanced;
+    def->set_default_value(new ConfigOptionFloat(0));
+
     def = this->add("fill_density", coPercent);
     def->gui_type = "f_enum_open";
     def->gui_flags = "show_value";

src/libslic3r/PrintConfig.hpp

@@ -639,6 +639,7 @@ public:
     ConfigOptionBool                extra_perimeters_overhangs;
     ConfigOptionBool                only_one_perimeter_top;
     ConfigOptionFloat               fill_angle;
+    ConfigOptionFloat               fill_angle_increment;
     ConfigOptionPercent             fill_density;
     ConfigOptionEnum<InfillPattern> fill_pattern;
     ConfigOptionPercent             fill_top_flow_ratio;
@@ -726,6 +727,7 @@ protected:
         OPT_PTR(extra_perimeters_overhangs);
         OPT_PTR(only_one_perimeter_top);
         OPT_PTR(fill_angle);
+        OPT_PTR(fill_angle_increment);
         OPT_PTR(fill_density);
         OPT_PTR(fill_pattern);
         OPT_PTR(fill_top_flow_ratio);

src/libslic3r/PrintObject.cpp

@@ -709,6 +709,7 @@ bool PrintObject::invalidate_state_by_config_options(const std::vector<t_config_
             || opt_key == "solid_fill_pattern"
             || opt_key == "enforce_full_fill_volume"
             || opt_key == "fill_angle"
+            || opt_key == "fill_angle_increment"
             || opt_key == "fill_pattern"
             || opt_key == "fill_top_flow_ratio"
             || opt_key == "fill_smooth_width"

src/slic3r/GUI/Preset.cpp

@@ -456,7 +456,10 @@ const std::vector<std::string>& Preset::print_options()
         , "top_fill_pattern"
         , "bottom_fill_pattern"
         , "solid_fill_pattern",
-        "infill_every_layers", "infill_only_where_needed", "solid_infill_every_layers", "fill_angle", "bridge_angle", 
+        "infill_every_layers", "infill_only_where_needed", "solid_infill_every_layers",
+        "fill_angle",
+        "fill_angle_increment",
+        "bridge_angle", 
         "solid_infill_below_area", "only_retract_when_crossing_perimeters", "infill_first", 
         "max_print_speed",
         "max_volumetric_speed",