[Radiance-general] estimating -av values, color

[Carsten Bauer]

> As far as I understood, the influence of the -av setting (on objects 
> not excluded from the ambient calculation) can be dimmed by the -aw 
> setting, and as I start my renderings with an "ouverture calculation" 
> the computed ambient distribution should be stable enough. Am I wrong 
> here?
>
hmm, I never used -aw so far, prob. I was to lazy to count the ambient 
vals to find out which number to set for -aw...

I think one point is important to consider: setting a constant 'rest' 
ambient value -av for the whole scene is a very crude thing which can be 
applied moderately to prevent certain regions appearing unnaturally 
dark, but it will be difficult to use -av as some kind of substitution 
on objects otherwise excluded from ambient ray tracing..
It quickly looks strange an unnatural either. I remember that it even 
was difficult to tweak things that way in POVRay, where you could (still 
can?) set
an ambient value for each material (resp. finish) separately..

-cb

PS -btw, the general problem was one of the backgrounds why I 
implemented such hacks as the secondary ambient material in radzilla for 
objects with complicated  patterns but still some sort of base color, or 
the 'scene' with its possibility of setting different ambient 
parameters, etc.
All serve in extending the range in which the raytracing ambient calc 
can still be used without letting rendering times explode. Because in 
the end the ambient rays are the only really working way of producing 
nice results, all other workarounds will sooner or later reach their 
limits..)