[Radiance-general] ar and aa

[Greg Ward]

I assume you meant to compare "-aa" and "-ar" in your first sentence.   
These are not two variables that affect the same behavior -- not much  
point in that.  Rather, think of the -ar setting as determining a  
scene resolution below which the accuracy of the indirect calculation  
(as determined by the -aa parameter) will start to relax.  If you  
divide your global scene size (the fourth value reported by "getinfo - 
d octree") by the -ar setting, you will get the scene size below which  
the indirect calculation will begin to lose accuracy.

Best,
-Greg

> From: Jia Hu <hujia06 at gmail.com>
> Date: July 16, 2010 8:17:48 PM PDT
>
> Hello experts:
>
> Is that right doubling the value of "aa" has the same effect as  
> decreasing the value of "aa" by half?  The minimum distance between  
> sampling points is the same according to the formula: SceneSize *  
> aa / ar.
>
> Cheer,
> Jia