[Radiance-general] mkillum with 400 sources?

[Greg Ward]

Hi Lars,

Putting illum surfaces inside of your windows rather than using a  
separate surface for each window pane is one way to reduce  
calculation times if your mullions are not particularly large or  
prominent.

All else being equal, you can reduce -ab by 1 and decrease -ad and - 
as (by a factor of 2 or so) and even increase -aa by 50% and still  
get similar results.  However, you may also have to set -dj .8 and - 
ps 1, which will undermine the calculation speeds a bit.  Overall,  
illum's pay off most when you have smaller windows or skylights and/ 
or complex goings on outside.

-Greg

> From: "Lars O. Grobe" <grobe at gmx.net>
> Date: October 9, 2005 9:22:57 AM PDT
>
> Hello again.
>
> I have to ask this in a more general way. I have used mkillum to  
> add some illum planes in front of the windows of my scene, and  
> sealed the sides using zero-radiance illums. I am rendering the  
> illums with -s=8 -d=8, and in total there are about 400 calculated  
> illums (and many more zero-radiance illums).
>
> Now, I am experiencing even slower calculation with rpict. I guess  
> it is because of all the illum sources. I think that I can reduce  
> the -ab bounces because of the illum useage, which will give faster  
> rendering times. But still I wonder if there is some kind of a  
> magic limit of the number of illums to use. I mean, is there a  
> number of illums where rendering speed decreases instead of  
> increasing by the useage of the mkillum-tool ?
>
> Are there any other ambient-parameters that I can change now that I  
> have illums? I am thinking of ad, ar, aa, as the light environment  
> is quite different now?
>
> You see, I am still quite a beginner in this mkillum stuff, and a  
> bit worried. Thanks for any help and hints, CU
>
> Lars.
>