OK, I've understood this....but i need to get out an angle, in particular i need to get the orientation of the cell on wich i've extracted the normal..do you know ho can i do this??? -- View this message in context: http://vtk.1045678.n5.nabble.com/normals-tp4932989p4933222.html Sent from the VTK - Users mailing list archive at Nabble.com.