On 18 Jun 2000 11:23:52 -0400, Warp wrote:
>Ron Parker <ron### [at] povrayorg> wrote:
>: we really need to fix the coincident surfaces problem to do it right.
>
>  Can it be fixed?
>
>  Let me guess: Calculate the intersection of the ray with the surfaces and
>then see if there's another intersection at a distance less than epsilon.
>Then take the average (?) of the color of the surfaces and treat both
>intersection as if they were just one.
>  Something like that?

In the general case, no, it can't really be fixed.  Probably the best we
could do is treat them as consecutive surfaces, but keep track of what order
they were evaluated in and always evaluate the same two surfaces in the same 
order everywhere (actually, they'd be evaluated in reverse order if the ray
started inside of them, but that's not too hard to deal with.)

The refraction problem can be solved more easily, though, without actually
solving the coincident surfaces problem.  It might even look physically 
correct.  It's just not what I'd call "right."

Anyway, this is getting out of .newusers territory.  Redirected to .general.

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

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