View Full Version : Maxwell Rendering Problem: Too Noisy

05 May 2007, 12:51 PM
Hey Everyone,

I got a problem with Maxwell. Whatever I do render it has lots of noise on it. I am increasing the sampling level and push render time up and up but it doesn't matter still i have the noise.

What i simply do is; I set up a scene with subdivs and polygons. I use maya and maxwell shaders. I don't set any light but use only maxwell's default light settings. I am executing maxwell directly from maya and usually use default settings in physical environment. As for a resolution i pick 640 x 480 and render time apprx. 5 mins. w/ 12 sampling level. I tried to render for an hour with 12 sampling levels, increased sampling level to 20 so on so forth... It doesn't matter... Still i have this noisy effect on it (like grains). Any idea how to solve it?

Thanks in advance...

05 May 2007, 01:03 AM
Well unfortunately that's what unbiased renderers (like Maxwell) are like. The only real solution is to render for longer.

The 'Sample Level' setting is not really a quality control, it's just another rendering time control. All renders will start out as a complete mess of noise, then as time goes by they get cleaner and cleaner until one of three things happens:

1. You press stop on the render yourself.
2. Maxwell reaches the 'Render Time' limit that you've set.
3. Maxwell reaches the 'Sample Level' limit that you've set.

It's not uncommon to use settings like 'Render Time' 99999999, 'Sample Level' 15. Because you might know from experience that your scene will look clean enough when it reaches SL 15 and you don't care how long it takes to reach that level.

Or the opposite way, 'Sample Level' 30 (that's very high), 'Render Time' 2 hours. There is no way you could reach SL 30, you just want the renderer to stop after 2 hours no matter what SL it ends up at.

Using the sky systems shouldn't really be that slow (in comparison to using lights), but any render will take a lot longer to clear up if you're using lots of glass or SSS materials.

05 May 2007, 07:44 AM
You must understand Maxwell as a real photograph, you know, real photos are noisy "per se", I mean, you never get a real noise-free photo, there is always some noise you can get rid of with photoshop and neat image, make neat image your friend with Maxwell also, it works pretty well! :)

05 May 2007, 08:15 AM
Thanks for your help. I just wanted to check out if everything was fine. I also saw a benchmarking table on the maxwell forums. That gave me a clue as well. Thanks again...

Lone Deranger
05 May 2007, 12:45 PM
I've noticed that using maya's own shaders tends to produce renders with "grainlike" artifacts. Not sure what's going on there.
It's not related to Shading Level type noise as the artifacts don't go away with longer render times and actually become more noticable as the SL noise progressively gets cleaned up.
They mainly show up as little specks slightly brighter than the colour they should be. Not sure if this is what you're experiencing, but replacing maya shaders with Maxwell's own did the trick for me. A bit annoying though...

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