yes, thank u. I've put it like this. double spacing[3]; bmp->GetOutput()->GetSpacing(spacing); double sx=spacing[1]; double sy=spacing[2]; double sz=spacing[3]; thank u. -- View this message in context: http://vtk.1045678.n5.nabble.com/what-s-wrong-with-this-tp5715424p5715426.html Sent from the VTK - Users mailing list archive at Nabble.com.