diff --git a/lib/Slic3r/TriangleMesh.pm b/lib/Slic3r/TriangleMesh.pm
index ea9e664e53..74efc39db3 100644
--- a/lib/Slic3r/TriangleMesh.pm
+++ b/lib/Slic3r/TriangleMesh.pm
@@ -585,8 +585,8 @@ sub horizontal_projection {
         push @f, Slic3r::Polygon->new([ map [ @{$self->vertices->[$_]}[X,Y] ], @$facet ]);
     }
     
-    $_->make_counter_clockwise for @f;
     my $scale_vector = Math::Clipper::integerize_coordinate_sets({ bits => 32 }, @f);
+    $_->make_counter_clockwise for @f;  # do this after scaling, as winding order might change while doing that
     my $union = union_ex([ Slic3r::Geometry::Clipper::offset(\@f, 10000) ]);
     Math::Clipper::unscale_coordinate_sets($scale_vector, $_) for @$union;
     return $union;