Any way to exclude objects/materials from the VRay Denoiser pass?

[D3Pixel]

Hi

The VRay denoiser works great but on several instanced objects that have fine scratch/smudge detail, it is denoising it to the point the fine details vanish. I tried the "Mild" setting which preserves the detail but then the rest of the image has too much noise.

Is it possible to easily exclude objects / materials from the denoising pass?

Thanks

[^Lele^]

Make a mask (cryptomatte, Multimatte) and in post it's a very easy task to accomplish.

[D3Pixel]

Ah right so switch to Multi-layer EXR and include "RGB Color" and "EffectResults" passes then install/use Cryptomatte (After Effects) to create the mask between them?

Does Cryptomatte work with animation saved via VFB yet or do I have to do all this via VRay Raw image file?

Cheers for the help.
Using VRay Next GPU rendering.

[^Lele^]

Correct.
You can save exr files from the raw file output of the VFB controls, in the render settings.
Make sure you render with the bucket sampler if a cryptomatte is what you want to use.
Otherwise you can get a wee bit better performance using simpler multiMattes with the objects/materials you'll want to exclude.

[D3Pixel]

Thanks for the advice, will give that a go.

[D3Pixel]

Well After much trial and error I gave up for this evening. All I wanted in the EXR was elements "RGB Color" , "EffectsResult" and the new Cryptomatte channel. Instead VRay added extra passes from the denoising and many other elements that I didn't want needlessly bloating the animation files to 50MB each. I tried to disable them in the denoiser advanced settings but it had no effect. Will give it another go when I have time to sit down and read the docs more carefully.

[^Lele^]

The channels are needed for the denoising process, and will get saved out if you save a multi-layer EXR (that allows for post-render denoising, with multi-frame support.).
You could however split out the REs (with the appropriate dialog in render settings) and delete what you don't need, or do the same in nuke on the multi-layer EXR.