Concerning my previous problem, a complete example is here: http://www.loria.fr/~roegel/tmp/problem.c The file is compiled under linux with gcc -o problem problem.c gl2ps.c -lglut -lGLU -lGL press `s' to save and wait for the print `scene saved in tmp.ps' In certain orientations, the output is incorrect. I have tested with and without the OCCLUSION_CULL flag. Denis