On 28 Dec 1999 15:33:32 -0500, Nieminen Juha
<war### [at] punarastascstutfi> wrote:

>  Answer: I'm not sure, but I have an idea. Perhaps someone could give it a
>try?
>  The shading could be calculated this way:
>  If the actual normal of the surface is pointing away from the light source
>while the modified normal is pointing at it, then we ignore the first
>intersection of the current object and the shadow ray calculated for this
>point.
>  Any comments?

One problem I can see is that it would be possible to create
pathological objects that might get shaded incorrectly as a result of
this workaround.  Non-closed, non-convex objects come to mind
immediately.  Perhaps we should make the workaround more explicit by
specifically having a "no self-shadowing" keyword?  Non-convex objects
still would act funny, but you could work around that if you needed to
by clever use of CSG.

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