From 05e7f63ffcd28e5d9c9c51d7695ecfba7a3bb97a Mon Sep 17 00:00:00 2001
From: Marius Kintel <marius@kintel.net>
Date: Mon, 2 Dec 2013 01:59:18 -0500
Subject: [PATCH] Don't convert empty clipper result to Polygon2d

---
 src/GeometryEvaluator.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/GeometryEvaluator.cc b/src/GeometryEvaluator.cc
index 9fffd364..84e93756 100644
--- a/src/GeometryEvaluator.cc
+++ b/src/GeometryEvaluator.cc
@@ -887,7 +887,7 @@ Response GeometryEvaluator::visit(State &state, const ProjectionNode &node)
 				// This is key - without StrictlySimple, we tend to get self-intersecting results
 				sumclipper.StrictlySimple(true);
 				sumclipper.Execute(ClipperLib::ctUnion, sumresult, ClipperLib::pftNonZero, ClipperLib::pftNonZero);
-				geom.reset(ClipperUtils::toPolygon2d(sumresult));
+                if (sumresult.size() > 0) geom.reset(ClipperUtils::toPolygon2d(sumresult));
 			}
 			else {
 				const Geometry *geometry = applyToChildren3D(node, OPENSCAD_UNION);