CompuServe Messages

Roger Most likely, there are a lot of normals pointing the wrong way. You could check this in 3dStudio's 3d Editor by using the successive commands: DISPLAY/GEOMETRY/BACKFACE and observing what disappears in the wireframe representation. If that's the problem, the fix can be very tedious. If the CAD designer didn't draw the model anticipating normal-directions, they are pretty much 50/50 right/wrong direction. It has been suggested that, for a quick still of the model, you apply 2-sided materials. While this doubles the rendering time, it may be acceptable for a single shot. It's pretty much UNacceptable for animations, not only for the doubled rendering time, but the quality of the animation suffers greatly frame-to-frame if you're using any 2 sided texture, opacity, reflection, or bump maps. For the past 2 years I've been involved in post-processing CAD (mainly AutoCAD) drawings to align the normal-directions correctly so that the files could then be used as the geometry in Wavefront Advanced Visualizer. I've found the same techniques work beautifully in 3DStudio. Try the 2-sided technique if that's acceptable; if not, zip up the drawing and EMAIL me a copy – I'd be glad to give you a proposal for the normalizing. Regards… Terry