diff --git a/lib/Slic3r/GUI/Plater.pm b/lib/Slic3r/GUI/Plater.pm
index 331aecaae6..be001cae7c 100644
--- a/lib/Slic3r/GUI/Plater.pm
+++ b/lib/Slic3r/GUI/Plater.pm
@@ -5,9 +5,9 @@ use utf8;
 
 use File::Basename qw(basename dirname);
 use List::Util qw(max sum first);
+use Math::Clipper qw(offset JT_ROUND);
 use Math::ConvexHull::MonotoneChain qw(convex_hull);
 use Slic3r::Geometry qw(X Y Z X1 Y1 X2 Y2 MIN MAX);
-use Slic3r::Geometry::Clipper qw(offset JT_ROUND);
 use threads::shared qw(shared_clone);
 use Wx qw(:bitmap :brush :button :cursor :dialog :filedialog :font :keycode :icon :id :listctrl :misc :panel :pen :sizer :toolbar :window);
 use Wx::Event qw(EVT_BUTTON EVT_COMMAND EVT_KEY_DOWN EVT_LIST_ITEM_ACTIVATED EVT_LIST_ITEM_DESELECTED EVT_LIST_ITEM_SELECTED EVT_MOUSE_EVENTS EVT_PAINT EVT_TOOL EVT_CHOICE);
diff --git a/lib/Slic3r/Geometry/Clipper.pm b/lib/Slic3r/Geometry/Clipper.pm
index 68e3d7c0e7..bef2713da5 100644
--- a/lib/Slic3r/Geometry/Clipper.pm
+++ b/lib/Slic3r/Geometry/Clipper.pm
@@ -14,12 +14,13 @@ our $clipper = Math::Clipper->new;
 
 sub safety_offset {
     my ($polygons, $factor) = @_;
-    return Math::Clipper::offset($polygons, $factor // (scale 1e-05), 100000, JT_MITER, 2);
+    return Math::Clipper::int_offset($polygons, $factor // (scale 1e-05), 100000, JT_MITER, 2);
 }
 
 sub safety_offset_ex {
-    # offset polygons and then apply holes to the right contours
-    return @{ union_ex([ safety_offset(@_) ]) };
+    my ($polygons, $factor) = @_;
+    return map Slic3r::ExPolygon->new($_),
+        @{Math::Clipper::ex_int_offset($polygons, $factor // (scale 1e-05), 100000, JT_MITER, 2)};
 }
 
 sub offset {
@@ -28,13 +29,18 @@ sub offset {
     $joinType   //= JT_MITER;
     $miterLimit //= 3;
     
-    my $offsets = Math::Clipper::offset($polygons, $distance, $scale, $joinType, $miterLimit);
+    my $offsets = Math::Clipper::int_offset($polygons, $distance, $scale, $joinType, $miterLimit);
     return @$offsets;
 }
 
 sub offset_ex {
-    # offset polygons and then apply holes to the right contours
-    return @{ union_ex([ offset(@_) ]) };
+    my ($polygons, $distance, $scale, $joinType, $miterLimit) = @_;
+    $scale      ||= 100000;
+    $joinType   //= JT_MITER;
+    $miterLimit //= 3;
+    
+    my $offsets = Math::Clipper::ex_int_offset($polygons, $distance, $scale, $joinType, $miterLimit);
+    return map Slic3r::ExPolygon->new($_), @$offsets;
 }
 
 sub diff_ex {
@@ -96,13 +102,19 @@ sub xor_ex {
     ];
 }
 
+sub ex_int_offset2 {
+    my ($polygons, $delta1, $delta2, $scale, $joinType, $miterLimit) = @_;
+    $scale      ||= 100000;
+    $joinType   //= JT_MITER;
+    $miterLimit //= 3;
+    
+    my $offsets = Math::Clipper::ex_int_offset2($polygons, $delta1, $delta2, $scale, $joinType, $miterLimit);
+    return map Slic3r::ExPolygon->new($_), @$offsets;
+}
+
 sub collapse_ex {
     my ($polygons, $width) = @_;
-    my @result = offset(
-        [ offset($polygons, -$width/2,) ],
-        +$width/2,
-    );
-    return union_ex([@result]);
+    return ex_int_offset2($polygons, -$width/2, +$width/2);
 }
 
 sub simplify_polygon {
diff --git a/lib/Slic3r/Layer/Region.pm b/lib/Slic3r/Layer/Region.pm
index c13b32760e..e4d8ee4763 100644
--- a/lib/Slic3r/Layer/Region.pm
+++ b/lib/Slic3r/Layer/Region.pm
@@ -96,12 +96,9 @@ sub make_surfaces {
     # detect thin walls by offsetting slices by half extrusion inwards
     {
         my $width = $self->perimeter_flow->scaled_width;
-        my $outgrown = union_ex([
-            Slic3r::Geometry::Clipper::offset(
-                [Slic3r::Geometry::Clipper::offset([ map @$_, map $_->expolygon, @{$self->slices} ], -$width)], 
-                +$width,
-            ),
-        ]);
+        my $outgrown = [
+            Slic3r::Geometry::Clipper::ex_int_offset2([ map @$_, map $_->expolygon, @{$self->slices} ], -$width, +$width),
+        ];
         my $diff = diff_ex(
             [ map $_->p, @{$self->slices} ],
             [ map @$_, @$outgrown ],
@@ -230,12 +227,7 @@ sub make_perimeters {
             # offsetting a polygon can result in one or many offset polygons
             my @new_offsets = ();
             foreach my $expolygon (@last_offsets) {
-                my @offsets = @{union_ex([
-                    Slic3r::Geometry::Clipper::offset(
-                        [Slic3r::Geometry::Clipper::offset($expolygon, -1.5*$spacing)], 
-                        +0.5*$spacing,
-                    ),
-                ])};
+                my @offsets = Slic3r::Geometry::Clipper::ex_int_offset2($expolygon, -1.5*$spacing,  +0.5*$spacing);
                 push @new_offsets, @offsets;
                 
                 # where the above check collapses the expolygon, then there's no room for an inner loop