Hi Antonio, what's the output of vtkImageData* imageData = conv->GetOutput(); imageData->Print(); //or should it say cout << imageData->Print(); kind regards Jochen -- View this message in context: http://vtk.1045678.n5.nabble.com/vtkVolume-vtkActor-tp5714227p5714268.html Sent from the VTK - Users mailing list archive at Nabble.com.