CompuServe Messages

The method Eric gave you should be just what you need. In the upcomming "3D Studio – Special Effects" book (due out this month) I wrote a chapter that goes into detail on doing this type of composite. Just render your animation or image normally, then render another version of it with a self illum white material (ambient, diffuse, and specular colors should all be 255,255,255) assigned to your objects, and with depth cue on. This will be used as an RGB mask for the frames to be composited over the background. Works like a charm, but I would suggest rendering the alpha frames to TGA's and not GIF's. It depends on your disk space and quality needs, but GIF is not really a true greyscale format, so they can produce dithering artifacts in the grey areas that can dirty up a composite. But they do require less space, so it's up to you. David