Thank you. That helped: 2) Try turning off the point/line/polygon smoothing and see if that's somehow interacting with the rendering. -- View this message in context: http://vtk.1045678.n5.nabble.com/vtkActor2D-problem-transparence-opacity-tp5739612p5739698.html Sent from the VTK - Users mailing list archive at Nabble.com.