I've been trying to make a rather blatent rip-off of an image on
http://www.sover.net/~tlongtin/, but as you can see in the attached image,
I'm having a small problem.  (OK, it's not an exact rip-off, the holes on
mine are more evenly spaced, and I have a class in differential geometry 20
years ago to thank for that.  OTOH, the textures on the original are not so
good, and mine are much, much worse.  Perhaps with a huge pile of greebles
added on... 8^)

I have (or at least should have) a properly enclosed mesh object, along with
an inside vector for it.  It's the green object in the image, if you haven't
guessed. 8^)  It's a mesh with some cylinders differenced out to make the
holes for the torus to go through.  I think it would be a huge pain to try
to compute the holes as part of the mesh, but it could be just because I
haven't thought about it enough.

The POVray help files say that this should be OK for CSG, but I get a parse
warning saying "Patch objects not allowed in intersection" at the closing
brace for my difference object.  And if you look carefully at the holes,
they don't have any depth like the edge of the band does.  (Or the holes in
the torus, which is the same thickness as the band.)

Also, the documentation talks about the vector as the location of a point
inside the mesh, but then talks about it as if it is some nebulous
direction for POV-Ray to shoot from random points to determine
"insidedness".  This is not the most clear exposition of the situation, and
could use some polish IMHO.  If someone will explain the exact algorithms
involved, I'll make a stab at cleaning it up a bit.

BTW, I am using POV-Ray version 3.6.1b.icl8.win32

Jon

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