diff --git a/lib/Slic3r/Fill.pm b/lib/Slic3r/Fill.pm
index 27b0434f0f..025a1cc006 100644
--- a/lib/Slic3r/Fill.pm
+++ b/lib/Slic3r/Fill.pm
@@ -52,7 +52,9 @@ sub make_fill {
     
     Slic3r::debugf "Filling layer %d:\n", $layerm->id;
     
-    # merge overlapping surfaces
+    # merge adjacent surfaces
+    # in case of bridge surfaces, the ones with defined angle will be attached to the ones
+    # without any angle (shouldn't this logic be moved to process_bridges()?)
     my @surfaces = ();
     {
         my @surfaces_with_bridge_angle = grep defined $_->bridge_angle, @{$layerm->fill_surfaces};
@@ -89,35 +91,10 @@ sub make_fill {
         }
     }
     
-    # add spacing between adjacent surfaces
+    # add spacing between surfaces
     {
         my $distance = $layerm->infill_flow->scaled_spacing / 2;
-        my @offsets = ();
-        foreach my $surface (@surfaces) {
-            my $expolygon = $surface->expolygon;
-            my $diff = diff_ex(
-                [ $expolygon->offset($distance) ],
-                $expolygon,
-                1,
-            );
-            push @offsets, map @$_, @$diff;
-        }
-        
-        my @new_surfaces = ();
-        foreach my $surface (@surfaces) {
-            my $diff = diff_ex(
-                $surface->expolygon,
-                [ @offsets ],
-            );
-            
-            push @new_surfaces, map Slic3r::Surface->new(
-                expolygon => $_,
-                surface_type => $surface->surface_type,
-                bridge_angle => $surface->bridge_angle,
-                depth_layers => $surface->depth_layers,
-            ), @$diff;
-        }
-        @surfaces = @new_surfaces;
+        @surfaces = map $_->offset(-$distance), @surfaces;
     }
     
     my @fills = ();
diff --git a/lib/Slic3r/Layer/Region.pm b/lib/Slic3r/Layer/Region.pm
index ee30232777..80f5aaa965 100644
--- a/lib/Slic3r/Layer/Region.pm
+++ b/lib/Slic3r/Layer/Region.pm
@@ -256,10 +256,13 @@ sub make_perimeters {
         
         # create one more offset to be used as boundary for fill
         {
+            # we offset by half the perimeter spacing (to get to the actual infill boundary)
+            # and then we offset back and forth by the infill spacing to only consider the
+            # non-collapsing regions
             my @fill_boundaries = @{union_ex([
                 Slic3r::Geometry::Clipper::offset(
                     [Slic3r::Geometry::Clipper::offset([ map @$_, @last_offsets ], -($perimeter_spacing/2 + $infill_spacing))], 
-                    +0.5*$infill_spacing,
+                    +$infill_spacing,
                 ),
             ])};
             $_->simplify(&Slic3r::SCALED_RESOLUTION) for @fill_boundaries;