Textures lost by denoising of mirrors

[Micha]

Hi,

at VfR 4 I have the problem that at the mirror the ground texture is over denoised. Is this a known problem? Is a workaround possible?

Best -
Micha

attached denoised and original

[seandunderdale]

Have you changed the denoise values? You can choose a "mild" preset or tweak the radius etc and hit update to see an update after the render. If these still dont work it probably means the denoiser sees you texture as noise, and thinks it needs to clean up. Id suggest saving a denoise render and a non-denoise render and selectively blending in post if the issue persists.

[Neilg]

turn on affect all channels in the material reflection.

[Micha]

I tried several thing snow, also changing affect channel, but nothing helps. BUT ... I switched to CPU mode and the problem is gone, the mirror area is perfect denoised, the texture details are kept. The difference between GPU and CPU is "impressive". I will send the scene to the support and hope, that it can be fixed soon.

Edit: I tested it at VfR5 beta and it's nearly the same problem - lost texture details in GPU mode, but not in CPU.

[Micha]

Here an other example, a simplified test scene - left GPU and right CPU. The denoiser of the GPU eat up the dark details. I'm very curious for a fix.

[Neilg]

By GPU, do you mean the nvidia denoiser, or in vray 5 is there a way to switch the vray denoiser between using the cpu or gpu?

or is this switching between cpu and gpu rendering, using the same denoiser?

[Micha]

I mean switching between GPU and CPU rendering using the V-Ray denoiser.

[cmascari]

I'd love to hear something from Chaos Group about this. As Micha knows from another thread, I too have noticed this behavior and posted about it. But back to Micha's original question, is there any fix underway for this? Or is there some workaround?

[nikoleta.garkova]

Hi all,

This is a known issue and is happening because of a difference in the Reflection pass of the two engines (which may very well be due to the 'affect all channels' option) as discussed here. In the linked post you can find a provided workaround.
It is logged as VGPU-4614 in our internal bug-tracking system. That being said, I will make a note to our devs and increase the priority of this.

[Micha]

Oh, that's hard. Such an old problem is still alive. GPU rendering is so promising, but ... I wished, there would be no "but".

[cmascari]

Thanks Nikoleta. Patiently awaiting a solution, glad to hear it has increased priority(hopefully that means sooner than VRay 6 ). I did read your workaround awhile back on the post you linked to, I just don't know how to do what you are suggesting. I dont know how to use After Effects. Guess I will have to learn.

[tsvetomira.girginova]

Dear all, hello.

The issue has been resolved in V-Ray 6. It was relevant to all V-Ray integrations.

You are able to receive proper results on V-Ray GPU with V-Ray 6 for 3dsMax hotfix 3 (6.00.20), V-Ray 6 for Rhino hotfix 1 (6.00.01) and later versions.
Mentioning only two host platforms, but you are able to find the exact build for others too if you navigate along the V-Ray Core version (should be =/> 6.00.20).

Best regards,
TS