[Radiance-general] Re: rtrace: strange behaviour

[Greg Ward]

> Francesco Anselmo responds to Schorsch:
>
> > Since this is the zenithal patch, that's the expected result.
> > Well, maybe not expected without seeing the code, but the ambient
> > ray distribution happens to have a small statistical irregularity
> > near the normal vector of the measuring plane.
>
> Oh, thanks for showing me the truth!
> So it is not possible to get the right result there ...

Actually, it should get the right result, but I wouldn't be surprised 
if the convergence was slow...  The sampling irregularity is due to the 
use of polar coordinates, which causes a convergence of sample areas at 
the normal (pole).  I should have adopted a different sampling strategy 
to maintain area aspect ratios, but this would have made the gradient 
calculation impossible.

More excuses as I am able to think them up.
-Greg