Sampling issues

[Rimas]

Hi, guys!

I've got a question about sampling. I think it's since the last update here VRay's adaptive sampling was introduced I started getting really crappy sampling in AO and certain other passes, which annoyed me on this latest job especially.

If you look at the images below - I think it's because the sampler just sees the white reflection as finished and doesn't give it any more samples (look at where the white reflection ends on the right side of both passes!) - which is fair for the beauty pass, but the same areas are also neglected in other passes, such as AO, where it makes no sense and makes for a very blotchy render with noise, which is quite annoying... Happens all the time now and I hate it because resolving those areas either requires manual intervention or leaving the image to render forever - neither of which is viable when rendering a job in bulk, say, via Backburner - and I have one job coming up where I'll have 300+ renders to make of various parts for a company.

Is there anything I can do about it beside having to focus rendering power on those areas every time I need an AO pass (area masks)???

Thanks!

[romullus]

If you think that's a new sampler's issue, did you try to switch to old sampler and see if that changes anything?

[Rimas]

I'll have to try that and see what happens. I left one image to render overnight on the new sampler and it did clear up after 16 hours xD

[Rimas]

I turned off adaptivity in the debug settings and that sorted the AO sampling problem - it's sampled as I would expect. Though, of course, the beauty pass is taking a bit longer to clear as a result.
Is this something to consider a bug or is it a "feature" we'll have to live with every time render passes are needed?

[maru]

I think this issue is similar to LightMix producing noise if specific light is completely turned off or increased a lot. So the beauty pass is mainly considered for sampling, and it does not really matter what is "underneath" some clean area (like that white spot in your examples). I would say this is expected as a result of using adaptivity.

Just a note - there are 3 things to distinguish:
1) The new light solver - exposed to the user at the top of performance tab, off by default, affects scenes when rendering many lights/complex lighting scenarios, our inhouse tech
2) The new random sampler - hidden in the devel/debug rollout, on by default, generally affects speed of noise refinement in the rendering, Chaos Group tech (the only in Corona right now)
3) The new enviro sampler - hidden in the devel/debug rollout, on by default,  affects noise mainly in scenes lit by HDRI, our inhouse tech

[Rimas]

I think this issue is similar to LightMix producing noise if specific light is completely turned off or increased a lot. So the beauty pass is mainly considered for sampling, and it does not really matter what is "underneath" some clean area (like that white spot in your examples). I would say this is expected as a result of using adaptivity.

Just a note - there are 3 things to distinguish:
1) The new light solver - exposed to the user at the top of performance tab, off by default, affects scenes when rendering many lights/complex lighting scenarios, our inhouse tech
2) The new random sampler - hidden in the devel/debug rollout, on by default, generally affects speed of noise refinement in the rendering, Chaos Group tech (the only in Corona right now)
3) The new enviro sampler - hidden in the devel/debug rollout, on by default,  affects noise mainly in scenes lit by HDRI, our inhouse tech

In my case, as already mentioned, it was the adaptivity. I turned that off and the AO pass rendered as normal and it's the first thing I tried - it's pretty obvious what the problem is.

My question is whether it's possible to have another way of sampling render passes later down the line while keeping the adaptivity for the beauty pass?