<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hi,<div> I really need some help with this problem! :-) Guys, I've tried many things, first with a plane source and then with a unstructured grid, converted it to a poly data and used vtkPolyDataNormals and set ComputeCellNormalsOn. It still doesn't give the desired results.</div><div><br></div><div></div></body></html>