Update on the spacing of perimeters.

#113

src/libslic3r/Flow.cpp

@@ -58,7 +58,7 @@ Flow Flow::new_from_spacing(float spacing, float nozzle_diameter, float height,
     // For normal extrusons, extrusion width is wider than the spacing due to the rounding and squishing of the extrusions.
     // For bridge extrusions, the extrusions are placed with a tiny BRIDGE_EXTRA_SPACING gaps between the threads.
     float width = float(bridge ?
-        (spacing - BRIDGE_EXTRA_SPACING) : 
+        (spacing - BRIDGE_EXTRA_SPACING_MULT * nozzle_diameter) :
 #ifdef HAS_PERIMETER_LINE_OVERLAP
         (spacing + PERIMETER_LINE_OVERLAP_FACTOR * height * (1. - 0.25 * PI));
 #else
@@ -78,7 +78,7 @@ float Flow::spacing() const
     float min_flow_spacing = this->width - this->height * (1. - 0.25 * PI);
     float res = this->width - PERIMETER_LINE_OVERLAP_FACTOR * (this->width - min_flow_spacing);
 #else
-    float res = float(this->bridge ? (this->width + BRIDGE_EXTRA_SPACING) : (this->width - this->height * (1. - 0.25 * PI)));
+    float res = float(this->bridge ? (this->width + BRIDGE_EXTRA_SPACING_MULT * nozzle_diameter) : (this->width - this->height * (1. - 0.25 * PI)));
 #endif
 //    assert(res > 0.f);
 	if (res <= 0.f)
@@ -94,7 +94,7 @@ float Flow::spacing(const Flow &other) const
     assert(this->height == other.height);
     assert(this->bridge == other.bridge);
     float res = float(this->bridge ? 
-        0.5 * this->width + 0.5 * other.width + BRIDGE_EXTRA_SPACING :
+        0.5 * this->width + 0.5 * other.width + BRIDGE_EXTRA_SPACING_MULT * nozzle_diameter :
         0.5 * this->spacing() + 0.5 * other.spacing());
 //    assert(res > 0.f);
 	if (res <= 0.f)

src/libslic3r/Flow.hpp

@@ -9,8 +9,8 @@ namespace Slic3r {
 
 class PrintObject;
 
-// Extra spacing of bridge threads, in mm.
+// Extra spacing of bridge threads, in mult of nozzle_width/extrusion_width. 0.05 for 0.4
-#define BRIDGE_EXTRA_SPACING 0.05
+#define BRIDGE_EXTRA_SPACING_MULT 0.125
 
 // Overlap factor of perimeter lines. Currently no overlap.
 #ifdef HAS_PERIMETER_LINE_OVERLAP

src/libslic3r/PerimeterGenerator.cpp

@@ -63,9 +63,9 @@ void PerimeterGenerator::process()
     // external loops (which is the correct way) instead of using ext_perimeter_spacing2
     // which is the spacing between external and internal, which is not correct
     // and would make the collapsing (thus the details resolution) dependent on 
-    // internal flow which is unrelated.
+    // internal flow which is unrelated. <- i don't undertand, so revert to ext_perimeter_spacing2
-    coord_t min_spacing     = (coord_t)( perimeter_spacing      * (1 - INSET_OVERLAP_TOLERANCE) );
+    coord_t min_spacing     = (coord_t)( perimeter_spacing      * (1 - 0.05/*INSET_OVERLAP_TOLERANCE*/) );
-    coord_t ext_min_spacing = (coord_t)( ext_perimeter_spacing  * (1 - INSET_OVERLAP_TOLERANCE) );
+    coord_t ext_min_spacing = (coord_t)( ext_perimeter_spacing2  * (1 - 0.05/*INSET_OVERLAP_TOLERANCE*/) );
     
     // prepare grown lower layer slices for overhang detection
     if (this->lower_slices != NULL && this->config->overhangs) {
@@ -353,7 +353,10 @@ void PerimeterGenerator::process()
                 if (i == 0) {
                     // compute next onion, without taking care of thin_walls : destroy too thin areas.
                     if (!this->config->thin_walls)
-                        next_onion = offset_ex(last, double( - ext_perimeter_width / 2));
+                        next_onion = offset2_ex(
+                            last,
+                            -(float)(ext_perimeter_width / 2 + ext_min_spacing / 2 - 1),
+                            +(float)(ext_min_spacing / 2 - 1));
 
 
                     // look for thin walls

src/libslic3r/PrintConfig.cpp

@@ -581,7 +581,7 @@ void PrintConfigDef::init_fff_params()
     def->full_label = L("External perimeters width");
     def->category = L("Extrusion Width");
     def->tooltip = L("Set this to a non-zero value to set a manual extrusion width for external perimeters. "
-                   "If left zero, default extrusion width will be used if set, otherwise 1.125 x nozzle diameter will be used. "
+                   "If left zero, default extrusion width will be used if set, otherwise 1.05 x nozzle diameter will be used. "
                    "If expressed as percentage (for example 112.5%), it will be computed over nozzle diameter.");
     def->sidetext = L("mm or %");
     def->mode = comAdvanced;

src/slic3r/GUI/PresetHints.cpp

@@ -266,15 +266,14 @@ std::string PresetHints::recommended_thin_wall_thickness(const PresetBundle &pre
 
     
     if (num_perimeters > 0) {
-        int num_lines = std::min(num_perimeters * 2, 10);
+        int num_lines = std::min(num_perimeters, 6);
-        out += (boost::format(_utf8(L("Recommended object min wall thickness for layer height %.2f and"))) % layer_height).str() + " ";
+        out += (boost::format(_utf8(L("Recommended object min (thick) wall thickness for layer height %.2f and"))) % layer_height).str() + " ";
+        out += (boost::format(_utf8(L("%d perimeter: %.2f mm"))) % 1 % (external_perimeter_flow.width + external_perimeter_flow.spacing())).str() + " ";
         // Start with the width of two closely spaced 
-        double width = external_perimeter_flow.width + external_perimeter_flow.spacing();
+        double width = 2*(external_perimeter_flow.width + external_perimeter_flow.spacing(perimeter_flow));
-        for (int i = 2; i <= num_lines; thin_walls ? ++ i : i += 2) {
+        for (int i = 2; i <= num_lines; thin_walls ? ++ i : i ++) {
-            if (i > 2)
+            out += ", " + (boost::format(_utf8(L("%d perimeter: %.2f mm"))) % i %  width).str() + " ";
-                out += ", ";
+            width += perimeter_flow.spacing()*2;
-            out += (boost::format(_utf8(L("%d perimeter: %.2f mm"))) % i %  width).str() + " ";
-            width += perimeter_flow.spacing() * (thin_walls ? 1.f : 2.f);
         }
     }
     return out;