HDRP Volumetric light produces white dots on thin walls

Hi there,

In an indoor scene I have a thin wall (0,1m large), with a strong volumetric light (spot) outside. I tried to reproduce it in the HDRP sample scene:



As you can see, there are a lot of white dots on the wall (it has been risen to let the light pass). If I scale the wall, the problem disappears. But sometimes we can't have thick walls. Is there any setting to avoid this? I tried with the shadow & fog settings, with no success. I'm using Unity 2019.3.0 with HDRP 7.1.5.

 

Hello,

since HDRP version 7.1.6 there is an option called Filter for the Fog volume. If you enable it, the noise of the fog will be much smoother. Also, there is another new option called Slice Distribution Uniformity, also under the Fog volume settings. The higher that value is, the more noise you get. Try to play with these options to get the desired result.

Too bad, Unity hide these great new options behind a cog icon and also turn them off by default. So nobody really knows.

 

You can often get away by just having the fog volume end before the wall, so tha there's no dense fog near the fall (less artifacts). Not a solution for all cases but worked for me... And you might also adjust the volumetric lighting quality to high, but this probably has quite high penalty performance-wise.

 

Indeed the filter value makes the fog smoother, but the wall still looks lit from behind :/ Nothing better with the Slice Distribution Uniformity (it doesn't seems to affect the noise quantity). The only workaround for now seems to be to place the Fog Volume just before the wall, as says Olmi.
Thanks you for your help (and sorry for the late feedback!).