diff --git a/src/AboutDialog.html b/src/AboutDialog.html
index 22ca9272..b2c2cc44 100644
--- a/src/AboutDialog.html
+++ b/src/AboutDialog.html
@@ -47,12 +47,18 @@ Please visit this link for a copy of the license: <a href="http://www.gnu.org/li
 <li><a href="http://gmplib.org/">GNU GMP</a>
 <li><a href="http://www.mpfr.org/">GNU MPFR</a>
 <li><a href="http://www.cgal.org">CGAL</a>
+<li><a href="http://www.angusj.com/delphi/clipper.php">Clipper</a>
 <li><a href="http://eigen.tuxfamily.org">Eigen</a>
 <li><a href="http://www.opencsg.org">OpenCSG</a>
 <li><a href="http://www.opengl.org/">OpenGL</a>
 <li><a href="http://glew.sourceforge.net">GLEW</a>
-<li><a href="http://qt.nokia.com">Qt Toolkit</a>
+<li><a href="http://qt-project.org">Qt Toolkit</a>
+<li><a href="http://www.riverbankcomputing.co.uk/software/qscintilla">QScintilla</a>
 <li><a href="http://www.boost.org">Boost</a>
+<li><a href="https://developer.gnome.org/glib">GLib</a>
+<li><a href="http://fontconfig.org">Fontconfig</a>
+<li><a href="http://freetype.org">Freetype</a>
+<li><a href="http://harfbuzz.org">Harfbuzz</a>
 <li><a href="http://www.gnu.org/software/bison/">Bison</a>
 <li><a href="http://flex.sourceforge.net/">Flex</a>
 <li><a href="http://www.cmake.org">CMake</a>
diff --git a/src/cgalutils-tess.cc b/src/cgalutils-tess.cc
index 7a8b80f0..f602d7b1 100644
--- a/src/cgalutils-tess.cc
+++ b/src/cgalutils-tess.cc
@@ -107,9 +107,9 @@ namespace CGALUtils {
 		else {
 			// Calculate best guess at face normal using Newell's method
 			CGAL::normal_vector_newell_3(polygons.front().begin(), polygons.front().end(), normalvec);
-			double sqrl = normalvec.squared_length();
-			if (sqrl > 0.0) normalvec = normalvec / sqrt(sqrl);
 		}
+		double sqrl = normalvec.squared_length();
+		if (sqrl > 0.0) normalvec = normalvec / sqrt(sqrl);
 
 		// Pass the normal vector to the (undocumented)
 		// CGAL::Triangulation_2_filtered_projection_traits_3. This
@@ -165,6 +165,8 @@ namespace CGALUtils {
 			// Calculate best guess at face normal using Newell's method
 			CGAL::normal_vector_newell_3(polygon.begin(), polygon.end(), normalvec);
 		}
+		double sqrl = normalvec.squared_length();
+		if (sqrl > 0.0) normalvec = normalvec / sqrt(sqrl);
 		
 		// Pass the normal vector to the (undocumented)
 		// CGAL::Triangulation_2_filtered_projection_traits_3. This
diff --git a/src/cgalutils.cc b/src/cgalutils.cc
index 9287608b..26e74522 100644
--- a/src/cgalutils.cc
+++ b/src/cgalutils.cc
@@ -892,6 +892,8 @@ namespace CGALUtils {
 	bool createPolySetFromNefPolyhedron3(const CGAL_Nef_polyhedron3 &N, PolySet &ps)
 	{
 		bool err = false;
+		// Grid all vertices in a Nef polyhedron to merge close vertices.
+		Grid3d<int> grid(GRID_FINE);
 		CGAL_Nef_polyhedron3::Halffacet_const_iterator hfaceti;
 		CGAL_forall_halffacets(hfaceti, N) {
 			CGAL::Plane_3<CGAL_Kernel3> plane(hfaceti->plane());
@@ -903,11 +905,22 @@ namespace CGALUtils {
 				CGAL_Nef_polyhedron3::SHalfedge_around_facet_const_circulator c1(cyclei);
 				CGAL_Nef_polyhedron3::SHalfedge_around_facet_const_circulator c2(c1);
 				PolygonK polygon;
+				std::vector<int> indices; // Vertex indices in one polygon
 				CGAL_For_all(c1, c2) {
 					CGAL_Point_3 p = c1->source()->center_vertex()->point();
-					polygon.push_back(Vertex3K(CGAL::to_double(p.x()), CGAL::to_double(p.y()), CGAL::to_double(p.z())));
+					Vector3d v = vector_convert<Vector3d>(p);
+					indices.push_back(grid.align(v));
+					polygon.push_back(Vertex3K(v[0], v[1], v[2]));
 				}
-				polyholes.push_back(polygon);
+				// Remove consecutive duplicate vertices
+				PolygonK::iterator currp = polygon.begin();
+				for (int i=0;i<indices.size();i++) {
+					if (indices[i] != indices[(i+1)%indices.size()]) {
+						(*currp++) = polygon[i];
+					}
+				}
+				polygon.erase(currp, polygon.end());
+				if (polygon.size() >= 3) polyholes.push_back(polygon);
 			}
 
 			/* at this stage, we have a sequence of polygons. the first