I am not sure whether this is related to QT or vtkPolyData, since in the official example, they used SetInputConnection(), but here I used SetInputData(). -- View this message in context: http://vtk.1045678.n5.nabble.com/vtkSelectVisiblePoints-and-vtkPolyData-tp5743324p5743325.html Sent from the VTK - Users mailing list archive at Nabble.com.