Smoke surface generating banding

[Swihartc]

Hey friends, I did a search for this and didn't see a direct answer. I'm having the issue to where using surface force is giving me banding.
spf 4
80mil cells for a 10' cubic box; scale 1
direct symmetric quality 100
render settings at default volumetric.
simple smoke opacity and color map rgb.

I messed with the isosurface settings, nothing changed so I believe thats more for the mesh renders?
There used to be an old tips and tricks section that showed this problem and I believe the answer was spf; but I am not sure if that is still the case. The output of the source is very small. If the grid is 10 feet, the output velocity is only 1/2 of an inch. I have also tried setting the surfaces to be not solid; still same issues.

Thank you for looking. If anyone knows of a similar thread, pls link

[Svetlin.Nikolov]

Yes indeed - in the fire/smoke solver, surfaces of sources are voxelized, so what you see are artifacts from the voxel grid. You could hide them from the rendering if you multiply the Smoke Opacity with a V-Ray Distance Texture: in the Smoke Opacity rollout, check "Modulate" and plug a DistanceTex in the Texture slot - pick the emitter geometry in the texture and set the near color to black and the far color to white and adjust the distance - this will reduce the opacity near the emitter. This technique is the same thing Hammer Chen shows in this setup, but used for the smoke instead of the fire: https://phoenixfd.blogspot.com/2019/...re-trails.html

[Swihartc]

Svetlin.Nikolov ahh yes thanks, the vraydistance texture I completely forgot about.