Hi, This behaviour is called zBuffer-Fighting. The only way to overcome this, is to slightly displace either the slice or the triangle. with best regards Jochen -- View this message in context: http://vtk.1045678.n5.nabble.com/Planes-in-the-same-space-tp5713813p5713819.html Sent from the VTK - Users mailing list archive at Nabble.com.