diff --git a/lib/Slic3r/ExPolygon.pm b/lib/Slic3r/ExPolygon.pm
index cee973e15..1dacdbacb 100644
--- a/lib/Slic3r/ExPolygon.pm
+++ b/lib/Slic3r/ExPolygon.pm
@@ -149,7 +149,11 @@ sub medial_axis {
     my $expolygon = $self->clone;
     my @points = ();
     foreach my $polygon (@$expolygon) {
-        Slic3r::Geometry::polyline_remove_short_segments($polygon, $width / 2);
+        {
+            my $p = $polygon->pp;
+            Slic3r::Geometry::polyline_remove_short_segments($p, $width / 2);
+            $polygon = Slic3r::Polygon->new(@$p);
+        }
         
         # subdivide polygon segments so that we don't have anyone of them
         # being longer than $width / 2
diff --git a/lib/Slic3r/Print.pm b/lib/Slic3r/Print.pm
index 9f08d4428..30e57b251 100644
--- a/lib/Slic3r/Print.pm
+++ b/lib/Slic3r/Print.pm
@@ -674,7 +674,7 @@ sub make_brim {
         # -0.5 because islands are not represented by their centerlines
         # (first offset more, then step back - reverse order than the one used for 
         # perimeters because here we're offsetting outwards)
-        push @loops, @{offset2(\@islands, ($i + 0.5) * $flow->scaled_spacing, -1.0 * $flow->scaled_spacing, undef, JT_SQUARE)};
+        push @loops, @{offset2(\@islands, ($i + 0.5) * $flow->scaled_spacing, -1.0 * $flow->scaled_spacing, 100000, JT_SQUARE)};
     }
     
     @{$self->brim} = map Slic3r::ExtrusionLoop->new(
diff --git a/t/shells.t b/t/shells.t
index 1077260dc..7120c0e7c 100644
--- a/t/shells.t
+++ b/t/shells.t
@@ -1,4 +1,4 @@
-use Test::More tests => 10;
+use Test::More tests => 11;
 use strict;
 use warnings;