Don't just ignore geometric nodes having zero volume/area - when doing difference/intersection, they tend to turn negative objects into positive ones. Fixes #221

1 files changed, 2 insertions, 3 deletions

diff --git a/src/CGAL_Nef_polyhedron.cc b/src/CGAL_Nef_polyhedron.cc
index ad2e4e2..8906595 100644
--- a/src/CGAL_Nef_polyhedron.cc
+++ b/src/CGAL_Nef_polyhedron.cc
@@ -61,7 +61,7 @@ CGAL_Nef_polyhedron &CGAL_Nef_polyhedron::minkowski(const CGAL_Nef_polyhedron &o
 
 int CGAL_Nef_polyhedron::weight() const
 {
-	if (this->empty()) return 0;
+	if (this->isNull()) return 0;
 
 	size_t memsize = sizeof(CGAL_Nef_polyhedron);
 	if (this->dim == 2) {
@@ -84,8 +84,7 @@ int CGAL_Nef_polyhedron::weight() const
 */
 PolySet *CGAL_Nef_polyhedron::convertToPolyset()
 {
-	if (this->empty())
-		return new PolySet();
+	if (this->isNull()) return new PolySet();
 	PolySet *ps = NULL;
 	if (this->dim == 2) {
 		ps = new PolySet();