Thin walls. #24

lib/Slic3r/Layer.pm

@@ -30,6 +30,10 @@ has 'slices' => (
     default => sub { [] },
 );
 
+# collection of polygons or polylines representing thin walls contained 
+# in the original geometry
+has 'thin_walls' => (is => 'rw', default => sub { [] });
+
 # collection of surfaces generated by offsetting the innermost perimeter(s)
 # they represent boundaries of areas to fill
 has 'fill_boundaries' => (
@@ -160,6 +164,19 @@ sub make_surfaces {
                 ($_, surface_type => 'internal'),
                 $surface->expolygon->offset_ex(-$distance);
         }
+        
+        # now detect thin walls by re-outgrowing offsetted surfaces and subtracting
+        # them from the original slices
+        my $outgrown = Math::Clipper::offset([ map $_->p, @{$self->slices} ], $distance);
+        my $diff = diff_ex(
+            [ map $_->p, @surfaces ],
+            $outgrown,
+        );
+        
+        push @{$self->thin_walls},
+            grep $_,
+            map $_->medial_axis(scale $Slic3r::flow_width),
+            @$diff;
     }
     
     if (0) {