Computation of vertex normals

Resuming the development of my OFF to VRML converter, I added one more feature: the computation of vertex normals. For this purpose I follow the method described in the Computer Graphics bible, Foley et.al "Computer Graphics: Principles and Practice in C" . In my approach I use the area of the adjacent polygons to determine the length of the normal vector.

Model with vertex normals and colored according to distance to barycenter