This raytracing tutor gets added to on and off as people express interest. It was written so that BASIC and other programmers would have something to work off of in developing rendering code, and it is my hope that not much more than what I've got here should be necessary to get someone going and interested. If there's an aspect you want more information on, send me a note and I'll see what I can do for you.
This is part of the Graphics Without Greek collection in the home pages of Dan Lyke , reachable at danlyke@flutterby.com