Good morning, Thanks Alex for reply, but i still have the same problem even with your suggestion. Any other suggestion please -- View this message in context: http://vtk.1045678.n5.nabble.com/unable-to-add-vertices-from-one-polydata-to-another-help-tp5716143p5716161.html Sent from the VTK - Users mailing list archive at Nabble.com.