imagedata.Update() is the answer. Ok, that was easy. I had just forgot to set an assignment to a global variable, so the problem wasn't even in the updating. -- View this message in context: http://vtk.1045678.n5.nabble.com/How-do-i-update-the-volume-tp5721925p5721926.html Sent from the VTK - Users mailing list archive at Nabble.com.