Dirty renders possibly from distributed rendering

[patrickf47]

Hello all, I am having an odd problem where when I set up a render on my farm it comes out looking dirty with little dark spots all over but when I render on my desktop it comes out clean. It reminds me of what can happen if you have two overlapping surfaces and try to render, but that is not the case. This file is a mesh which I think my have to do with the problem but I honestly am at a loss.

Anyone have any ideas? I attached each render to show what I'm talking about.

Thanks in advance for any help

[Micha_cg]

Never seen here. Is it VfR 1.05 or 1.5? Can you see error messages on the process windows of the spawner on the slaves? Maybe something related to the LC/IM?
Maybe it works with "use for glossy rays" of the LC.
Are spawner and master using the same VfR version?

[patrickf47]

All the computers used in each of the renders I attached are on vray for rhino v1.5. There are no errors in the process and all the renders complete, just with the "dirt". This only seems to happen with meshes, nurbs models I have not seen this happen with.

I tried adjusting the light caching but it seems to have only made the issue worse :/

[fpedrogo]

I have never seen this issue either. If you send us the scene file I can look at it and give you a precise solution.
vrayrhino@chaosgroup.com

Best

[patrickf47]

Thank you so much, sending the scene now

[patrickf47]

Follow up after more testing

It is not the distributed rendering process that is causing my problem. I noticed the renders that were coming out "dirty" had parallel checked off in the viewport properties, projection settings. So my next question is what is the difference between parallel and prospective projection and what is causing parallel to appear dirty?

Thanks

[moegamat]

I experienced a similiar problem if, I disable DR then alls well, seem to be a glitch

[Micha_cg]

Follow up after more testing

It is not the distributed rendering process that is causing my problem. I noticed the renders that were coming out "dirty" had parallel checked off in the viewport properties, projection settings. So my next question is what is the difference between parallel and prospective projection and what is causing parallel to appear dirty?

Thanks

Is your model far away from point 0,0,0? If yes, this can cause mesh display problems at the Rhino viewport some times, maybe for VfR too.

[fooprobe]

I bet Micha's right on this - a parallel view is axonometric or orthographic, not perspective - that is there's no lens, and if I recall correctly Vray doesn't do true axon, it approximates it by placing the camera very far away and using a super long lens. And then you get the bad mesh.

[moegamat]

This is the first time i experienced this glitch in Vray, I use a generic named view. The only snag with my system is my SSD is running low on space, not sure if this was the issue. its working fine now

[Micha_cg]

Same problem here today (I use VfR 1.5 seldom only). I don't used DR, but if I switch to a parallel camera view than I get the errors. Seems to be a numerical error that need to be fixed. I will try to send a bug report.

[Micha_cg]

Can repeat the bug anymore.

Maybe it has something to do with the physical camera or the missing bias parameter at some lights.

[renee81]

I never had that problem,and I use parallel view quite often to do elevation.

[fpedrogo]

I tested your scene and I'm not able to reproduce the issue. I saw that you were using Adaptive subdiv for this render, this AA method could produce weird sampling with reflective, refractive and blurry materials. I recommend you to switch to Adaptive DMC.
Long time ago I got some black spot similar to your issue, but were related to the welding option of the imported mesh and also with the UVW mapping. I don't think this is your case, but I mentioned this just in case someone have similar issues.


Best

[Micha_cg]

At my model it was like the render mesh was a little bit visible.