From ca8a91b2b07d8ac2b197a7be05e3c88df3175122 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Thu, 14 Jun 2012 15:06:22 +0200
Subject: [PATCH] Only apply arc compensation to circular holes. #418

---
 lib/Slic3r/Layer.pm | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/lib/Slic3r/Layer.pm b/lib/Slic3r/Layer.pm
index c4df761f..c242e8dd 100644
--- a/lib/Slic3r/Layer.pm
+++ b/lib/Slic3r/Layer.pm
@@ -225,6 +225,11 @@ sub make_perimeters {
         foreach my $hole ($last_offsets[0]->holes) {
             my $circumference = abs($hole->length);
             next unless $circumference <= $Slic3r::small_perimeter_length;
+            # this compensation only works for circular holes, while it would 
+            # overcompensate for hexagons and other shapes having straight edges.
+            # so we require a minimum number of vertices.
+            next unless $circumference / @$hole >= scale 3 * $Slic3r::flow->width;
+            
             # revert the compensation done in make_surfaces() and get the actual radius
             # of the hole
             my $radius = ($circumference / PI / 2) - scale $self->perimeters_flow->spacing/2;