fog/mist noise

[ynachev]

Hey guys, i'm trying to add fog/mist in a scene i'm making and i'm struggling cleaning the noise from the atmosphere pass without using a lot of AA
Is there a way to make it smoother without increasing my image sampler subdivs ?
You can see what i'm talking about in the attached image, with low AA settings there's a lot of noise in there
Sorry if that's something obvious but i haven't used Phoenix for other than fluids till now

[ynachev]

Here is a screenshot of the settings i'm using:

[georgi.zhekov]

Apart from increasing the AA you can try to go to the Smoke Color Options and turn off the Light Cache - this will help cleaning the noise in some cases.

[georgi.zhekov]

You are using really low samples with high noise threshold in VRay.

Try with 1/8 and noise threshold of 0.01

[ynachev]

Yeah, i intentionally lowered the AA so i can see how noisy the atmosphere pass is without it's help, isn't there a way to control the Phoenix smoke subdivs separately ?

[georgi.zhekov]

No, there are separate subdivs only for the Light emission.

Why do you need such a thing? It's far easier to control everything from one place.

[ynachev]

I thought that cleaning the noise with something other than AA would be faster, because the render times are really slow when i try to use normal subdivisions for the AA
I tested it on a really small region and it's pretty slow, even though i have a clay material override, you can see the render time in the history tab, and the atmosphere pass is still noisy

[georgi.zhekov]

That's the way to go unfortunately.

You do have pretty large sim with relatively low opacity smoke and you render a high resolution image.

Rendering thicker smokes will be faster. You can try and turn on the Probabilistic option - https://docs.chaosgroup.com/display/...phere+Settings and check if this helps.

[ynachev]

Hey Georgi, thanks for the help, i figured as much since the case is pretty complex, i'll just have to be patient
By the way, Phoenix still renders faster then the mapped Environment Fog i tried to use in the beginning, and it looks better