diff --git a/lib/Slic3r/Layer/Region.pm b/lib/Slic3r/Layer/Region.pm
index b130f7828..a3b6abe06 100644
--- a/lib/Slic3r/Layer/Region.pm
+++ b/lib/Slic3r/Layer/Region.pm
@@ -216,7 +216,7 @@ sub make_perimeters {
         my @gaps = ();
         
         # generate perimeters inwards (loop 0 is the external one)
-        my $loop_number = $Slic3r::Config->perimeters + ($surface->additional_inner_perimeters || 0);
+        my $loop_number = $Slic3r::Config->perimeters + ($surface->extra_perimeters || 0);
         push @perimeters, [] if $loop_number > 0;
         
         # do one more loop (<= instead of <) so that we can detect gaps even after the desired
diff --git a/lib/Slic3r/Print/Object.pm b/lib/Slic3r/Print/Object.pm
index 6ba47f64e..80f5889f6 100644
--- a/lib/Slic3r/Print/Object.pm
+++ b/lib/Slic3r/Print/Object.pm
@@ -237,11 +237,10 @@ sub make_perimeters {
                 my $overlap = $perimeter_spacing;  # one perimeter
                 
                 my $diff = diff_ex(
-                    [ offset([ map @{$_->expolygon}, @{$upper_layerm->slices} ], -$overlap) ],
                     [ offset([ map @{$_->expolygon}, @{$layerm->slices} ], -($Slic3r::Config->perimeters * $perimeter_spacing)) ],
+                    [ offset([ map @{$_->expolygon}, @{$upper_layerm->slices} ], -$overlap) ],
                 );
                 next if !@$diff;
-                
                 # if we need more perimeters, $diff should contain a narrow region that we can collapse
                 
                 $diff = diff_ex(
@@ -252,17 +251,17 @@ sub make_perimeters {
                     ) ],
                 );
                 next if !@$diff;
-                
                 # diff contains the collapsed area
                 
                 foreach my $slice (@{$layerm->slices}) {
-                    my $hypothetical_perimeter_num = $Slic3r::Config->perimeters + 1;
+                    my $extra_perimeters = 0;
                     CYCLE: while (1) {
                         # compute polygons representing the thickness of the hypotetical new internal perimeter
                         # of our slice
+                        $extra_perimeters++;
                         my $hypothetical_perimeter = diff_ex(
-                            [ offset($slice->expolygon, -($perimeter_spacing * ($hypothetical_perimeter_num-1))) ],
-                            [ offset($slice->expolygon, -($perimeter_spacing * $hypothetical_perimeter_num)) ],
+                            [ offset($slice->expolygon, -($perimeter_spacing * ($Slic3r::Config->perimeters + $extra_perimeters-1))) ],
+                            [ offset($slice->expolygon, -($perimeter_spacing * ($Slic3r::Config->perimeters + $extra_perimeters))) ],
                         );
                         last CYCLE if !@$hypothetical_perimeter;  # no extra perimeter is possible
                         
@@ -273,8 +272,7 @@ sub make_perimeters {
                         );
                         last CYCLE if !@$intersection;
                         Slic3r::debugf "  adding one more perimeter at layer %d\n", $layer_id;
-                        $slice->additional_inner_perimeters(($slice->additional_inner_perimeters || 0) + 1);
-                        $hypothetical_perimeter_num++;
+                        $slice->extra_perimeters($extra_perimeters);
                     }
                 }
             }
diff --git a/lib/Slic3r/Surface.pm b/lib/Slic3r/Surface.pm
index d5ec9838e..efa0f46a9 100644
--- a/lib/Slic3r/Surface.pm
+++ b/lib/Slic3r/Surface.pm
@@ -11,7 +11,7 @@ use constant S_EXPOLYGON    => 0;
 use constant S_SURFACE_TYPE => 1;
 use constant S_DEPTH_LAYERS => 2;
 use constant S_BRIDGE_ANGLE => 3;
-use constant S_ADDITIONAL_INNER_PERIMETERS => 4;
+use constant S_EXTRA_PERIMETERS => 4;
 
 use constant S_TYPE_TOP             => 0;
 use constant S_TYPE_BOTTOM          => 1;
@@ -24,7 +24,7 @@ sub new {
     my %args = @_;
     
     my $self = [
-        map delete $args{$_}, qw(expolygon surface_type depth_layers bridge_angle additional_inner_perimeters),
+        map delete $args{$_}, qw(expolygon surface_type depth_layers bridge_angle extra_perimeters),
     ];
     $self->[S_DEPTH_LAYERS] //= 1; #/
     
@@ -36,7 +36,7 @@ sub expolygon       { $_[0][S_EXPOLYGON] }
 sub surface_type    { $_[0][S_SURFACE_TYPE] = $_[1] if defined $_[1]; $_[0][S_SURFACE_TYPE] }
 sub depth_layers    { $_[0][S_DEPTH_LAYERS] } # this integer represents the thickness of the surface expressed in layers
 sub bridge_angle    { $_[0][S_BRIDGE_ANGLE] = $_[1] if defined $_[1]; $_[0][S_BRIDGE_ANGLE] }
-sub additional_inner_perimeters { $_[0][S_ADDITIONAL_INNER_PERIMETERS] = $_[1] if defined $_[1]; $_[0][S_ADDITIONAL_INNER_PERIMETERS] }
+sub extra_perimeters { $_[0][S_EXTRA_PERIMETERS] = $_[1] if defined $_[1]; $_[0][S_EXTRA_PERIMETERS] }
 
 # delegate handles
 sub encloses_point  { $_[0]->expolygon->encloses_point }