I have a question with regards to a project I am trying to do. I am using Daniel Shiffman's open Kinect library in combination with the Triangulate library. I am trying to find the normals of the triangles,but because  the normals depend on the order of the triangles vertexes as their position changes constantly, the order of the triangles vertexes keeps on changing together and then not always I get the correct normal vector. So, my question is: Is there any other way other than cross product to find a perpendicular vector to a triangle? Thanks a lot for you time in advance. Buzz