Vray Volume Grid and Light Select

[CCX]

Hi,
We have a vray volume grid which has a cache of an explosion from Fume Fx.
As the explosion goes up, the smoke gets lit by couple of lights in the environment.
Our compers asked if we could render out the smoke with each light separated.
we tried using light select, but it seems to work only with geometry. We tried volumetric Geometry on the volume grid, but still of no use.
At the moment we are rendering using different render layers, isolating the selected lights.
But is it possible to the get the light select working for volumetrics ?

Thanks

[Miro]

Thank you for the pointer. We have reported it as a bug and will update this thread with any news.

According to my tests, the issue doesn't occur with the Progressive sampler in Volumetric geometry rendering mode . Can you confirm if it is the same on your end?

[CCX]

Hey,
Thanks for the update.
and wow, yeah. with the progressive sampler and in volumetric geometry mode, it works.
This is a saviour. Thanks for the tip.
But the only issue is, with progressive I am not able to get the similar noise free render as with adaptive sampling.
Any suggestions on matching the rendering quality with adaptive while considering the render times.

[Zdravko.Keremidchiev]

Generally the Progressive image sampler can't be optimized much, the idea there is that you need to wait until it refines the image to the required quality. Which in your case maybe slower than the adaptive sampling. Every image sampler have its pros and cons.

[vlado]

But the only issue is, with progressive I am not able to get the similar noise free render as with adaptive sampling.

Ideally the progressive sampler should produce identical results to the adaptive one. Do you get a message that the Phoenix FD light cache is disabled for progressive rendering? This might be a reason for the increased noise.

Best regards,
Vlado

[CCX]

Ideally the progressive sampler should produce identical results to the adaptive one. Do you get a message that the Phoenix FD light cache is disabled for progressive rendering? This might be a reason for the increased noise.

Thanks Vlado,
But i don't see that message when rendering. But when I disabled motionblur its a bit faster and the results are indentical. Only that it takes longer to render. , But still takes longer to computer as i had to increase the Max transparency levels to
100 as i turned on volumetric geometry.

This one is adapative rendered with adaptive sampling under 2 seconds

While this one is rendered in Progressive, which took around 2mins.

and i did another test with unchecking Use Light Cache in volume grid with a render time of 1min 46 sec.

[CCX]

Hi,
any update on the bug fix for this. I am still using progressive sampler and raytracing in self shadowing ( if i used Grid spacing, there is flicker between frames)
and with the raytracing enabled in self shadowing. its hard to get a cleaner image.
you can see it in the attached image.

[Svetlozar Draganov]

We are sorry to report but this is not fixed yet, the fix is planed for the next major release.

[CCX]

No problem, thanks for the update.
we have managed using bucket sampler and render layers and a lot less noise than the progressive sampler.