Noisy Light

[byronnash]

I'm getting some noise on the shadow side of this grass hill I'm rendering. My Adaptive DMC is set to .014 and I'm using the Nederhorst settings. I'm using a Vray Sun/Sky as well as a dome light to bring the shadows up some. What do I need to adjust to get the noise to go away in the areas I am pointing to in this image? I originally thought it might be the Dome light Sampling Subdivisions (set to 8 now). But I did some single frame A/B tests I couldn't see much difference. The render passes we have seem to point to it being the Dome light but I'm stumped on what to adjust.

[Dariusz Makowski (Dadal)]

So basic troubleshooting.

Set up

RAW light
Raw Reflection
Specular

If noise is in light - increase light samples
If noise is in reflection - increase reflection samples
If noise is in specular - increase light samples.

[byronnash]

Thanks DADAL. Looks like more light samples it is! What are some "normal" levels? 16, 32?

[Dariusz Makowski (Dadal)]

Depending which AA sampler you are using. Subdivision require a lot less sampels than Adaptive DMC. Also it depends on IBL source.

[byronnash]

I'm testing different values in my dome light>Sampling>Subdivs> and I don't see a result in the beauty, raw light or light select passes. Am I adjusting the wrong parameter? I'm using the VFB to A/B each setting.

[byronnash]

I'm using sun\sky with no IBL. Would Subdivision sampling give better results in this high frequency detail image?

[Dariusz Makowski (Dadal)]

So where is the noise ? In ur Raw light pass? How does ur Sample rate looks like? Can u show these 2 renders.

[byronnash]

Did a test render overnight with Fixed Rate set to 10. The noise is much reduced. Are you asking to see my render settings or image files? I have some light select passes going and we noticed that the dome light one was noisier than the sunlight one. I just don't understand why the light subdivisions doesn't fix it.

[Dariusz Makowski (Dadal)]

Its DMC sampler that kick in and ruins ur settings. Lower the adaptive amount from 0.75 to 0.5 that will clean it up. Also I'd like to see both render and settings.

[byronnash]

Here are my DMC settings and some frames. The noise is a bit hard to see in a still since it's a visually noisy image. Looks like the adaptive amount was already set to .6-ish.

[Dariusz Makowski (Dadal)]

Set min AA sampler to either 2 or 3. That should give it some clean up
Set the Dome light samples 2 or 3x higher.
Set Adaptive amount to 0.5 if above results didnt give good enought results.

Alternatively u can try Adaptive Subdivision with min 1 max 2 but then u have to re-edit ur light subd...

Hope this helps.