Proper MR Area Light Settings

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  02 February 2005
Proper MR Area Light Settings

Does anyone knows how to set mr's arealight settings?
How do you set Sampling, Low Level and Low Sampling for best results and fast rendertimes?

sal.yashu.
 
  02 February 2005
Area lights sampling

Sampling:
the higher the number - the nicer result you will get, but rendering will take longer.
Try 10 max 15 (usually thats OK). Keep in mind that MR area light is expensive effect it if you want nice results you got to make compromise between time and quality. Try 8 -6 but result will be grainy.

Low level sampling deals with secondary rays, if u have shadows in reflections, u can tell MR to render them with lower quality (low level). To do that u show set low level to 1 (ON) and then adjust that level samples as u wish 2x2 is default. Mental Ray will calculate them separately and that can help u render scene faster.

Area lights use to achiev soft lighting effects, u can achieve these effects in other less expensive ways.
 
  02 February 2005
Originally Posted by TrysD: To do that u show set low level to 1 (ON) and then adjust that level samples as u wish 2x2 is default. Mental Ray will calculate them separately and that can help u render scene faster.

Not quite correct. The low level value is not a boolean (0 off/1 on), it manages the level of reflection/refraction depth at which the arealight stops sampling shadows at high level rate. So for a value of 2 for instance, the shadow will be sampled in reflections/refractions at the given high level rate until the 2nd reflection/refraction of an object but beyond that at the given low level rate. 0 (zero) means the 'high level' sampling rate is being used always. That's at least how I got that whole stuff, barely needed that.

It appears that using high sampling rates beyond 1 blows out (direct) illumination in places close to an arealight. You can avoid this by leaving the sampling at 1 and increasing the antialiasing/sampling per pixel - and therefore increasing the rendering time even more, but you will get very smooth lighting in exchange, which I personally like very much.

Further I noticed finalgather artifacts (bright blotchy spots, looking like render errors) if the low sampling rate is less than 3 or 2. But this happens in rare cases only (when placing the arelight very close to objects), so just if you run into it..
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  02 February 2005
Thanx for your replies. Oh, does anyone knows how to use the 'User' setting in the Area Light MR section? In mr docs it says that I can make any geometry an area light, but how do you do this in maya?
thanx again.
 
  02 February 2005
It definitely works in mentalray standalone, however I never found a solution to get it to work from within maya.. maybe in 6.5, have to check this out.

This thread might be of interest for you:
http://www.cgtalk.com/showthread.php?t=193842
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Six Tuts On Light And Shade
 
  02 February 2006
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