IPR runs faster in the Viewport than VFB

V-Ray V-Ray for Blender V-Ray for Blender :: Issues
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1

Hello,

I don’t know if this is a bug/issue or just a matter of settings, but when I run the IPR on the Viewport, it quickly denoises the scene, while using the VFB it takes a while for sampling and then denoising the scene.

The weird part is if I open the VFB and run the IPR both in the Viewport and VFB, they ‘syncronize’ and sample and denoise at the same time.

I’m using Blender 5.0.1 / V-Ray 7.30.20 revision 597 from june 24/26

Viewport IPR:

VFB IPR:

Viewport and VFB:

This is even worst with real scenes.

2

There’s a parameter for this in our render settings - System/V-Ray Frame Buffer called Image Effects Update Frequency. For the viewport we always set it to 100 so the denoiser runs as quickly as possible. For the VFB it is controlled manually from there with a default of 10 as it can have a rendering performance cost.

3

Humm good to know. But even changing the Image Effects to 100, there’s still a delay and some artifacts happens during the preview (the white squares below), while in the Viewport it is instantly clean.

These artifacts/fireflies disappear and come back after some samples.

Screenshot_1
Screenshot_1931×813 76.3 KB

Here’s a recording of the same scene:

The thing is, when viewport is running, the VFB behaves the same way and both have the same “clean” result. The issue happens only if the IPR is running through VFB only.

4

Those artifacts look a bit like the V-Ray denoiser which is slower and should generally be used for production renders. The viewport engine and the VFB denoiser can be different, the parameters in the viewport menu in the screenshot control which denoiser is used during viewport rendering. The denoiser parameters in the render setting control which denoiser will be used during production/VFB(non-viewport) interactive. You can also link the two with the Linked Denoiser toggle.

image
image1167×695 119 KB

5

Perfect! Thanks! I changed the denoiser and it behaves exactly the same now.

Another question. Is it possible to have a denoiser for production and another for interactive render (same as for viewport)?

Currently the viewport and vfb display slightly different colors so this could be a workaround until we have things working