[Radiance-general] Slow rendering with transparant textures

[Lars O. Grobe]

> One of the slowest things in Radiance is the .cal file evaluations, so 
> minimizing expression evaluations is the key to faster renderings in 
> this case.  Having many surfaces for each ray, all having function 
> evaluations, is bound to be slow.  Combining or eliminating such calls 
> would help a lot.  I don't know enough about your situation to 
> recommend "how."
Greg hi,

I got curious now when I hear about eliminating such calculations. As 
far as I know, I alsways have to at least rotate anything mapped that I 
want to appear on a non-horizontal surface. I can avoid scaling, 
mirroring etc by applying these tranforms to the images using image 
processing tools such as those coming with radiance. But for avoiding 
the rotation, I do not see a way (besides rotating the whole model with 
light sources and views instead of the images if e.g. I want to map most 
onto a vertical plane). So did you mean something like that when saying 
"eliminating such calls", or were you thinking about structuring them 
more efficient?

CU Lars.