Ken wrote:
> 
> "Jerome M. BERGER" wrote:
> >
> > Peter Popov wrote:
> > >
> > > Not if the thickness is 0, like box { <-1000,0,-1000>, <1000,0,1000> }
> > > which, though odd, is perfectly legal.
> > >
> >         I didn't know you could do that... Doesn't it raise coincident surface
> > problems, though? Or does POV handle it in a specific way?
> >
> >                 Jerome
> 
> It handles it just like a triangle with no problems with coincident surfaces.
> Renders much faster than a plane does too. Try it you'll like it :)
> 
	Still has to be hollow it seems, I've just run a test and it loks like
the "other side" of the box is "inside" no matter what your point of
view is...

	Here are the results of my test renders of a simple scene:

			with fog	without fog
0.0001 units box	113s		70s
1000 units box		64s		46s
0 units box		62s		44s
plane			59s		40s

	Note that since I didn't specify "hollow", the 0.0001 units box is the
only one which showed the fog properly. Other than that, all four
solutions were identical visually.
	I don't know how POV handles boxes and planes internally, but if I were
to make a raytracer and optimize boxes and planes as far as I can, the
planes should be faster (and neither would be bounded, I mean what's the
point of bounding a box when it's already the faster finite shape you
can compute?).

	These results were obtained with uvpov6.1 but I don't think official
POV would make much of a difference.

		Jerome

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