VFB Issue with Denoiser not working after LightMix changes

[matt_laver]

Hi Guys,

This is my first time here on the forums as I'm new to V-Ray. I'm hoping someone can help.

I have a problem when using the VFB to make LightMix changes after the render; when I make a change to any of the lights in the LightMix layer the Denoiser seems to switch off and looks like it is re-calculating. However it just thinks for a few seconds and then stops, leaving the image noisy, as if I'd turned the Denoiser layer off. The same happens when I uncheck the Denoiser layer in the Layer panel. The noise appears, as you would expect, but when I re-check the Denoiser Layer to make it visible again the noise remains, as if the Denoiser hasn't come back on.

Also, once I make any changes in the LightMix layer, and then load a different image, those changes to the original image are lost when I return to the original image. The 'Mix' has reset. I appreciate I can save a LightMix preset but should I have to re-load the 'Mix" settings every time I want to work on the image?

I hope that all makes sense, because at the moment I can't use LightMix as a tool due to the Denoiser behaviour.

Any thoughts?

Sketchup 2021, V-Ray 5 1.5, Mac OS 10.13.6

T.I.A

Matt

[nikoleta.garkova]

Hi matt_laver and welcome!

The described behavior is odd, I've tested on SketchUp 2021 and V-Ray 5, update 1.5 - the Denoiser takes a while after making an adjustment in LightMix, but it will eventually show the denoised result. Moreover, turning off/on the Denoiser, it also seems to work. Can you give us some additional info, such as:

• Have you noticed this behavior on previous V-Ray versions, or is it something new?
• Which Denoiser are you using? Is there any difference switching between V-Ray/Intel Open Image?
• Does this happen in every project - even the simplest one?

Other than that, if you wish to get the same settings you can either save a LightMix preset or you can use the 'To Scene' option so you could push the adjustments directly to the project - next time it renders, you will have those adjustments applied.

[matt_laver]

nikoleta.garkova Hi Nikoleta, and thanks for responding so quickly.

Regarding your questions; I have seen this happening before intermittently, but I was able to rectify it by restarting V-Ray. Now I can't rectify it. It seems to have become permanent around the time of updating to the latest version of SketchUp 2021 or V-Ray 1.5.
I'm using the Intel Open Image denoiser as the others either produce hugely long render times or poor results, on my system.
I've tried rendering a much simpler project and the results are the same, with the Denoiser not working if I switch it off/on or change any LightMix setting.

I was following the suggested workflow of running a production render with the lights neutralised and boosted slightly, to enable low noise lighting refinement after the render, but before output. Thus avoiding the need to re-render after making the changes. Otherwise why bother with the LightMix at all and rather finalise everything pre-render.

Thanks,
Matt

[nikoleta.garkova]

Hey matt_laver,

Thank you for the clarifications. I am still unable to reproduce such behavior on our end, see recording: http://ftp.chaosgroup.com/support/sc...3_17-30-49.mp4
Can you also provide some videos demonstrating what's happening on your end? Maybe I'm missing something out or there could be something additional that plays a role. Can you still switch Denoisers to see if it behaves any different on V-Ray Denoiser?

We could also schedule a remote session at your convenience so we could troubleshoot this on the spot, just drop us a line on our contact form and make sure to mention this thread in the subject.