> Heh heh. I knew I should have qualified that and said basic primitives, in
which
> group I include torus. I was thinking, of course, of the following:
>
> sphere
> box
> cylinder
> cone

The reasons for not including the torii's position in the first few
parameters have to do with the way torus intersections are calculated,
mathematically, at the lowest level. I believe that factoring in a
translation inside the *base* intersection calculation would make the
calculation slower. Translations, on the other hand, are a type of
transformations, which are applied *separately* from the base intersection
calculations, and are only applied when necessary.

Trust me, it makes sense when you work out the math yourself =)

 - Slime
[ http://www.slimeland.com/ ]

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