Blurred render, washy spots

[Ales_Al]

Hello!

I've recently switched to the newest version of V-Ray.


Now when trying to render same scene (a bit different angle) I'm getting pics with blurred images and some unknown spots.
Has anyone come across this issue?

[konstantin_chaos]

Hi Ales_Al,

The blurring as well as the spots are caused by denoising.
It seems you have either the NVIDIA AI or the Intel denoiser active in the project.


What's interesting is why wasn't the denoiser working before you upgraded?
Can you share the original model for further investigation on our side?

Regards,
Konstantin

[Ales_Al]

konstantin_chaos I recall rendering with Denoiser turned on in the past. Following your advice I've switched it off now. You can see the result attached. Sharing render settings for V-Ray I had for the render

https://drive.google.com/drive/folde...an?usp=sharing

[konstantin_chaos]

Hi Ales_Al,

It makes sense.
With the Denoiser On you'll see some artifacts but the image is much smoother from the very beginning.
When the Denoiser is Off there will be visible noise and you'll have to wait a lot longer before it clears.

Konstantin

[andy_smith]

Hi Ales_Al,

It makes sense.
With the Denoiser On you'll see some artifacts but the image is much smoother from the very beginning.
When the Denoiser is Off there will be visible noise and you'll have to wait a lot longer before it clears.

Konstantin

Sorry - quick question: is there a recommended approach to using the denoiser? Are you suggesting that, in the Render rollout of the Asset Editor, we should typically set the Denoiser switch to off? If so, is there then a different way to denoise the image later? My assumption was that, with the Denoiser switch set to off, V-Ray wouldn't produce a denoised version of the render and you'd be left to do it later in, say, Photoshop but you've said "you'll have to wait a lot longer before it clears" which implies that V-Ray will still denoise the image even with the switch set to off.

[konstantin_chaos]

Hi andy_smith ,

It is recommended to use either the NVIDIA AI or the Intel Open Image denoiser during interactive rendering since they can produce lighting fast results.
Note that the Update Effects slider has to be set to Rapid for the interactive denoising to work best.
When it's time to render a final image using the production rendering mode it is recommended to switch to the V-Ray Denoiser.
You can also set the Update Effects slider to the left to ensure you're not spending too much time denoising. It can even be set to "At the End".

...you've said "you'll have to wait a lot longer before it clears" which implies that V-Ray will still denoise the image even with the switch set to off.

If you wait longer V-Ray will sample the image more and hence decrease the visible noise.
The image quality improvement in this case will not be because of denoising but thanks to the image sampling itself.

My assumption was that, with the Denoiser switch set to off, V-Ray wouldn't produce a denoised version of the render and you'd be left to do it later in, say, Photoshop

When the Denoiser toggle is off, V-Ray will not perform any denoising.
It is also worth mentioning that denoising the image in Photoshop after you've saved it is not possible. At least not with the quality that V-Ray is capable of.
V-Ray has a high dynamic range multichannel image to work with when denoising 'in the VFB'.
If you save the image from the VFB as a V-Ray image or a Multichannel EXR file you can perform denoising with the standalone V-Ray Denoiser tool.
If however you save out a regular 8bit image and you use a 3rd party tool for denoising, the results will never be as good.

I hope that the information here helps,
Konstantin