Noise threshold per object or material?

[peterguthrie]

Forgive me if this is a stupid question, but as I use the universal settings 99% of the time this would really help. Very often using the universal settings with a noise threshold works great for everything apart from white walls, any noise tends to get lost in textured or darker materials. If there was some way to combat the noise that is evident in lighter areas it would be very very handy.

The thing I love about the universal settings is that I don't waste any time struggling with settings or test renders, it usually just works. (I recently did a project where I spent about 4 days in total trying different techniques, from irradiance map to BF + LC (and using large material subdivs rather than relying on DMC sampler) I never got anywhere, and would have been quicker in the end sticking to the universal method!)

With digital cameras, noise often seems to be most pronounced in the darker areas, with vray, it seems to be the opposite (thats just an observation, not a complaint)

I think I read another wishlist item for AA DMC sampling per object, would some kind of noise threshold per object or material be possible?

If technically not possible, is there some other strategy I could adopt? A typical scenario would be that on an interior shot, everything looks good (noise free or acceptable) at a noise threshold of 0.01, but the white walls would require the threshold to be lowered to 0.005

Thanks, Peter

[super gnu]

http://www.chaosgroup.com/forums/vbu...reshold+object


http://www.chaosgroup.com/forums/vbu...reshold+object


http://www.chaosgroup.com/forums/vbu...reshold+object


http://www.chaosgroup.com/forums/vbu...reshold+object

[peterguthrie]

ok, so I'm not the only one

[super gnu]

to be honest its mostly me posting there.. buuut, i believe our wishes may be answered soon

[BBB3]

Interesting! Care to say more?

[super gnu]

only going by Vlado's comment here:

http://www.chaosgroup.com/forums/vbu...reshold+object

[pixela]

So looking froward to the spring service pack!

[Morbid Angel]

Quite honestly I do not see the need for per object control. I mean, I know what you need and lots of control is good. But typically you can solve any noise by understanding where its coming from. There are several contributing factors to noise:
For example your wall has noise, but you say everything else is clean. Split out your passes (render elements) and see which of them has the noise, at that point you can tell what is the contributing factor, i.e. a surface has a really low glossy value and not enough samples = grainy reflection, even for universal settings.

If you have grain in lighting, then its the overall quality of your lights and so on, if you are able to identify the cause, you can solve it quite easily in vray.

[super gnu]

for me i have a very specific issue that i believe cannot be resolved in an efficient way in vray at the moment.

its distance shimmer in big masterplan animations. particularly trees.


in order to get a really clean horizon, you need massively high AA settings, and a very low noise threshold. and AFAIK nothing else will fix it.


trouble is if you have massively high aa settings, and a low noise threshold, then your shadows and moblur and refs etc in the foreground, will get massively oversampled. even turning down the subdivs on those individual parameters you still have way too many samples. ive had scenes that look fine up to middle distance and render in about 10 mins a frame, but in order to resolve the shimmer in the further portions of the scene, ive had to bump up aa till my frames are taking 1-2 hrs. and a lot of that time is spent rendering the foreground.


ive been asking for more fine grained control of the noise threshold over an image, which has tied in with those asking for per-object control. i agree with you really that per-object isnt immensely useful, as you have plenty of per-material controls you can use to affect the sampling of a single object. at a mimimum id like a distance or environment range multiplier on the noise threshold or aa subdivs. but i have an idea that far more flexible (for even unexpected future uses) would be the ability to control noise threshold with a map. obviously unless this was compatible with procedural (rendertime) maps, you would need to pre-render masks, which would be far from ideal, but still, extremely flexible. maybe a simple distance multiplier is the best compromise.

[cecofuli]

Peter, you are right, but in the next years, we must lose the habit of having 1,000 parameters. The main problem in VRay i that with the Universal Setting (the best "near" unbiased methond without twaking) where there are situations where VRay gets really slow, compared to competitors Unbiased (Fryrender for example). We are rendering a small shopping center with many lights (+100) and glass lamp. We must move inevitably to IM + LC + Detail enhancement. Otherwise, the render times would be, trust me, catastrophic! In this case, the noise goes in second plane ^_^

[peterguthrie]

For example your wall has noise, but you say everything else is clean. Split out your passes (render elements) and see which of them has the noise, at that point you can tell what is the contributing factor, i.e. a surface has a really low glossy value and not enough samples = grainy reflection, even for universal settings.

(thanks for your reply) So even with universal settings, could I try upping the subdivs on a problematic mat or light? I did actually try this a few days ago: setting the subdivs on a problematic (light coloured) wood material progressively up to 1000 made no visible difference but did negatively affect render times. Maybe the lights were the problem though.

On the noisyness thing, it's not that other materials are noise free, more that you don't see the noise as its hidden by textures ( I think anyway)

[Morbid Angel]

per object noise control and per object AA is two different things. On the other hand, 1-2 hours a frame isn't that bad in my opinion. Lastly, you shouldn't have to oversample by more then 3 min samples in the image ever, which does not slow down the render time that much.

[Morbid Angel]

(thanks for your reply) So even with universal settings, could I try upping the subdivs on a problematic mat or light? I did actually try this a few days ago: setting the subdivs on a problematic (light coloured) wood material progressively up to 1000 made no visible difference but did negatively affect render times. Maybe the lights were the problem though.

On the noisyness thing, it's not that other materials are noise free, more that you don't see the noise as its hidden by textures ( I think anyway)

Whats your dmc sampler set to?

[peterguthrie]

Whats your dmc sampler set to?

just as per http://www.spot3d.com/vray/help/200R...nisettings.htm

adaptive amount 1.0 but noise threshold usually 0.01 for a final render (at say 3000-4000px). Test renders usually 0.05

I'm quite sure that when Vlado first introduced the universal settings the recommended noise threshold was 0.01. Now the advice on spot3d seems to be 0.005 for a clean render

[Morbid Angel]

Well, Im not positive that this method works now as it was in 1.5. Indeed new vray has some difference in the way dmc sampler works with a high number of samples.