Artifacts when using Fog Color

[kosso_olli]

Hey guys,
I have a scene here where using Fog Color to create tinted glass causes square-shaped artifacts that seem to line up with the edgeflow. See attached screenshot.
Reducing the depth value makes the artifacts disappear, but I lose the level of tinting I need.
A few years ago I created a similar thread, but it was never fixed:

https://forums.chaos.com/forum/v-ray...sing-fog-color

[^Lele^]

Why not colour the refraction to get back the tinting?
Also, mind sharing the piece of geo with me for (a refreshed) investigation?

[kosso_olli]

Sure thing, scene file was sent to your mail.
Tinting the glass via refraction color does work, but it does not feel right.

[seandunderdale]

are the verts welded / merged?

[^Lele^]

Yes, the geo is fine, but low poly.
As a workaround for this, i suggested the use of a vrayDisplacementMod in subdivision mode, without texture, to subdivide the glass geo down to 1px of edge lenght, which removes the faceted look at the cost of some preprocess time and some RAM.

[kosso_olli]

Still, it must have something to do with the geo. Creating a plane of similar tesselation, bent and with a shell of the same thickness, I do not get those artifacts.

[^Lele^]

i tried a few things, nothing was noticeably out of order.
welded vertices, smoothed normals.

[seandunderdale]

if you export out as obj and bring back in, is it still fucky? obj often strips out gremlins.

[kosso_olli]

Might be worth a try.