[Radiance-general] Solar Rays Tracing path

[Lars O. Grobe]

Hi!

> Someone did and included it in the distribution. I think it's called
> xshowtrace.

Good hint. However, I think that this use case would require to go from 
the source, not from the view point. I guess that one could get rtrace 
to get the intersection and direction vectors by taking the light source 
as first view point. But I am not aware of anyone who did that.

Cheers, Lars.