Volume & Area Light > noise

[jeremyshin]

Hello again,

I face this problem since too long now and couldnt find a fix.

I have a Volume object which generate animated smoke, and inside the Volume container I have a small area light. I want the light to reflect on the animated smoke.
Everything works great but i have huge amount of noise just nearby the light source (see attached picture).

I tried almost everything :
- GI Clamp is almost at minimum.
- Increasing sample max just increase uselessly my render time for cleaning such a small area.
- Reducing the power of the light doesnt give me the look I want and it doesnt fix the noise problem.
- I already use adaptive sampling.
- My area light is not behind a specular material.
- Light samples are at 200. (other lights at 100, so it should allow 2x more samples as far as i understood)
- PMC is better but incredibly long render time (i rendered with PT for animation)

Other ideas are welcome ~

[bepeg4d]

Hi jeremyshin,
do you mind to post a screenshot of the light and the kernel settings?
ciao beppe

[jeremyshin]

Sure ~
See the attached files

Thank you mate !

[bepeg4d]

Hi jeremyshin,
sorry, could you post also a screenshot of the Camera Imager, and the Volume Medium node, thanks.
ciao beppe

[jeremyshin]

Here it is ~
Thank you

[bepeg4d]

Hi jeremyshin,
please, try to remove the rgb nodes in absorption and scattering, and use gaussian spectrum node instead.
Then in kernel settings:
Max samples 8000
choerent ratio = 0.5
Parellel samples = 16
Max tile =32
Adaptive sampling:
0.05
512
1
none

ciao beppe

[jeremyshin]

Thanks I will try those settings
choerent ratio = 0.5 will not make my animation flicker ?

[jeremyshin]

Removing the rgb nodes in absorption and scattering, and use gaussian spectrum node instead makes my volume disappear.
Anything to fix that ?

[bepeg4d]

Hi jeremyshin,
yes, because the default setting are not equal to the original colors.
Please, convert your RGB nodes to HSV and take note of the Value for both, then set the Width of the Gaussian node at 1, and the Power equal to the Value in HSV.
In this way it should be very similar.
Coherent ratio at 0.5 with 8000 samples should not give any flickering, with Static noise option active.
ciao beppe

[jeremyshin]

I reply late, sorry ~
I tried all what you said for the gaussianspectrum, nothing worked I got no color in the volume, everything is black.
I guess I am missing something but I dont know why... RGBspectrum give me colors, Gaussianspectrum don't.
You have any idea Beppe ?
Thanks