On Sun, 13 Jan 2002 12:24:55 +0200, Eugene Arenhaus wrote:
> How? Easy. You write a Trace routine for transparency shader that will
> create two more ray objects (passing and bouncing), cast them (by
> calling Scene's Trace routine), combine the result in its single ray and
> return that. 

Exactly how some very interesting Renderman shaders work.

-- 
#macro R(L P)sphere{L F}cylinder{L P F}#end#macro P(V)merge{R(z+a z)R(-z a-z)R(a
-z-z-z a+z)torus{1F clipped_by{plane{a 0}}}translate V}#end#macro Z(a F T)merge{
P(z+a)P(z-a)R(-z-z-x a)pigment{rgbt 1}hollow interior{media{emission T}}finish{
reflection.1}}#end Z(-x-x.2y)Z(-x-x.4x)camera{location z*-10rotate x*90}

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