[Radiance-general] sharing the ambient cache

[Greg Ward]

Well, I should have made a caveat about reducing the -ab parameter.   
If your -av setting is not well-chosen, or if the lighting varies  
drastically over your scene, reducing -ab in subsequent runs could  
result in splotch artifacts.  You would have to try it, but that's  
what I would expect.

-Greg

> From: Jack de Valpine <jedev at visarc.com>
> Date: December 22, 2005 8:20:14 AM PST
>
> Hi Greg and Rob,
>
> The strategy that we have always used is based on John's  
> recomendations in RwR. For example:
>
> parameter
> 	first pass (overture at 64 or 128 pixels)
> 	second pass (whatever your next resolution is)
> -ad
> 	1024
> 	512 (1/2 of first pass)
> -as
> 	512
> 	256 (1/2 of first pass)
> -aa
> 	.15
> 	.25
>
> In RwR, John does not recommend changing the other ambient  
> parameters. However, I am intrigued to hear that Greg indicates  
> that it would be ok to reduce -ar as well as -ab. It would be  
> interesting to run some test and determine what good reduction  
> parameters would be.
>
> Now, we use the parameter reductions mainly for "pictures." I am  
> interested to consider what kind of parameter reductions would work  
> when moving from a tight grained high -ab quantitative simulation  
> to something that could still use the ambient cache for producing  
> "pictures," which is more clearly what Rob is thinking about.
>
> -Jack