WXYZ is a quaternion or rotation matrix and has a complicated formula to transform to aer. How did you change the orientation of the actor? Max -- View this message in context: http://vtk.1045678.n5.nabble.com/GetOrientation-in-vtk3DProp-tp5722036p5722175.html Sent from the VTK - Users mailing list archive at Nabble.com.