Cleaning render reflections

[MartinDarzacq]

Hello, I have quite a noob question to ask...

I was wondering how to clean the "white noise" on this image properly. With a sample rate min :1 max:100 I can't get rid of the noise (left part).
Using min:30 max:30 I get a super clean result. But is that the correct workflow? I've always been taught not to touch the minimum sample rate...I would like your opinion
This is a simple scene with a Vray sun+sky.

Portals did not help, by the way are we still supposed to use it with vray sun or not anymore like the new Hdri system?

[Alex_M]

Hi,

You can try adding a denoiser render element. Use the Mild preset since the noise is not that much from what I can see.

As far as I know, portals are not needed anymore with Vray Next. If you use an HDRI, just turn on Adaptive dome setting in the dome light and it will take care of complex situations like small openings in an interior and will speed up the rendering.

[Morbid Angel]

1/100 means very little if the noise threshold is not low enough. High dmc noise threshold will not use max 100 and never clean that. This is why when you set to min 30 you force all samples to be min 30 and get the clean result, I bet if you set the sampling to 1/24 but noise threshold to 0.005 it would be just as clean but faster render. min/max 30 is not a correct workflow with adaptive image sampler.

[Morbid Angel]

Here is a quick series of images I've done to help explain the workflow.










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[MartinDarzacq]

Thank you very much for your answers!
I did some experimentations this morning :
-first, i removed the Vraysky from the environment and linked it in a vraydome light instead to see if I could get the benefits of the new dome system. It did render a little bit faster.
-then I rendered a few tests to compare the effects of the noise threshold and Mild Denoiser.

Those crops are around 230% zoom of a 4000px long render. As I zoomed in, I guess I have to push it to 0.002+denoiser to get a professional standard final render? what do you think?

[Morbid Angel]

The clean render level depends on the time you have and the project quality level. If you have a lot of render power and some time you may produce high quality clean render by lowering the noise threshold and giving vray a lot of max subdivs. Its a trade off really. I don't like using denoiser or any biasing / post processing after the fact, but for interior stills it might just be the thing if used mildly (*not very strong denoising might help) but in my experience it causes more issues then it solves.

Also be aware that when zooming in to the render and checking noise level you are trying to evaluate noise in a zoomed image, while the renderer did not sample that noise at the zoomed level, so you will always see noise when zooming in. So long as the render looks clean at 100% that is a satisfactory result to me.

[MartinDarzacq]

Thank you Sir glad I had your opinion! I will keep experimenting. Indeed Denoiser has a tendency to remove a lot of the fine details