Hi Ryan, Wow, I have not heard anybody bring up TOPAS, ever. I was a reseller, my clients were NASA, and PBS. I got pretty good at it, driving it from script files and geometry models I created from C programs. The following link shows the result, an accurate roller coaster reconstruction from blueprints of the original ride, and a Euler integration of gravity based on track slope, for the acceleration along the track. I'll see if I can dig up a copy for you. I runs fine in dosbox selecting a hi-res VGA instead of a Targa card. The Truvision stuff was a kick, for a while there it was the high water mark in computer graphics, competing well against more powerful Silicon Graphics and Wavefront. http://www.youtube.com/watch?v=DJ7V7O_mfcs Randy