So all the points from a 3d plot are saved, from back to front? That seems like an odd way to save 3d information to a 2d format. I suppose that it avoids having to compute a new image, ignoring the points that  would be invisible, but it sure does waste space. Still, the eps files contain some 3d information, in that any point that will be overwritten as it is rendered is behind the new point... not enough info to do a complete 3d reconstruction though.

Thanks, Robert.

John Starrett