strange render noise error ...

[ingoerik]

... on the GarageFarm renderfarm, on my computer it renders fine (their support is working on it but is a little helpless too). Does anybody have a clue ? Looks like a problem with the hdri domelight. Threshold is 0.002, BruteForce/LightCache.
Added another comparsion picture between the rendering on my computer and on the renderfarm. Looks to me like an error with adaptive sampling.

[ingoerik]

Okay, found the problem, its the adaptive light sampling for the dome lights that cause the problem, if i switch it off everything renders fine. Anyone from Chaos Group can say anything to it ??

[Robert]

That could be related to the EIS settings. If you have local sampling turned on, try turning it off and just use the default GI settings in the GI tab. If you still need local sampling, increase the Environment settings. In the new nightly version of V-Ray you also have the Adaptive option, that works well for still images. However garage farm still using the official build of V-Ray and not the nightly. Maybe check out ChaosCloud if that helps, they offer support for nightly versions.
Anyway, this all should be better with V-Ray 5.0 .. but its not in sight for Modo yet.

[ingoerik]

I have no local sampling on, its the default global sampling.

It gets even more weird, my scene has a large opening at the top and is lit only with the domelight. When i add an additional arealight just the size of the opening the image gets darker as if the arealight is blocking the incoming light, when i turn the intensity of the arealight from the default to above 5 everything looks like it should be.

Btw, have you successfully used Rebus with VRayforModo ? On their website it says that its supported, but when i ask support i get no answer.

[Robert]

Well, as far as I heard they all switched to render the vrscene file only. It has advantages when uploading scene again and they just need to use vray stand alone. There are exception like 3dsmax.
I told the people at garage farm that they loosing quite a lot money that I now spend on chaos cloud, because of the vrscene format. The disadvantage lies in deformers and motion blur. This can lead to really huge files on animation, so uploading a 6 GB file for 100 frames is not fun.
Anyway, I never used Rebus. There are so many farms and I heard that there are some really good ones for Modo. Do a search on the Modo forum to get more information.
The difference between ChaosCloud and the others is, that ChaosCloud uses as many servers, as Jobs are online. So its dynamically increasing. This like constantly rendering on high priority, minus half of the costs. On other farms you need to plan, when to upload and what priority to give. Also Chaos Cloud is refunding you the money for failed jobs. I once paid over $300 for a failed job on garage farm. Some V-Ray bug. But that was pretty unfair, as it wasn't my fault.

[ingoerik]

Thanks for the info, i will give ChaosCloud a try, it seems that i can even use the denoiser on their farm. I just hope it works better now with high resolution stills.

[Robert]

You can also try GPU rendering in progressive mode. That can work fine on noisy scenes