From 9fd063799057fd5404dbcbf188b916487eedc339 Mon Sep 17 00:00:00 2001
From: Alessandro Ranellucci <aar@cpan.org>
Date: Mon, 5 Jan 2015 21:00:50 +0100
Subject: [PATCH] Bugfix: artifacts were introduced when perimeters were
 recalculated through incremental slicing. #2494

---
 xs/src/libslic3r/LayerRegion.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xs/src/libslic3r/LayerRegion.cpp b/xs/src/libslic3r/LayerRegion.cpp
index f068cf24f..7b8e77f5a 100644
--- a/xs/src/libslic3r/LayerRegion.cpp
+++ b/xs/src/libslic3r/LayerRegion.cpp
@@ -44,7 +44,8 @@ void
 LayerRegion::merge_slices()
 {
     ExPolygons expp;
-    union_(this->slices, &expp);
+    // without safety offset, artifacts are generated (GH #2494)
+    union_(this->slices, &expp, true);
     this->slices.surfaces.clear();
     this->slices.surfaces.reserve(expp.size());