Subject: the umbilic torus
Date: Tue, 29 Jun 2004 20:26:29 EDT

Hi Dr. Bob,

Well, it's been raining here in Texas for days.  Not too hot but very humid. 
With the image, you were right, I just set a constant IOR for the entire solid and the computer did the rest.   Here's another one, only this time I made the surface highly reflective and not transparent at all.  I'm using a program called POVRay.  Check out  It is a "ray-tracing" program.   I think that how it basically works is by computing thousands of rays from the camera viewing plane into a scene and letting the rays bounce or bend when they strike surfaces, depending on various definable surface attributes, hence the name "ray-tracing".  I think that rays are also computed from light sources.  This is the kind of technology that makes the animation in movies like Lord of the Rings.