Combing artifacts in shadows

[Seanoskea]

I see this weird comb effect a lot. I don’t even know what to call it to search for why it happens. It seems to happen with landscape meshes created in Unreal and in mesh imported from Blender. Love to be pointed at something that I can do to fix this. Thanks

While poking around, I’ve discovered its coming from the directional light. If I put a point light next to the mesh and turn off the directional it disappears. Lumen yes/no Nanite yes/no up to 1024 on the lightmass no effect. Raytraced yes/no none of this seems to matter only turning off the sun. This example comes from a tunnel mesh with one sided material so the outside of the cylinder is invisible. But I have seen this exact same effect on landscape mesh generated in Unreal.

[ClockworkOcean]

Are you using Nanite?

[Seanoskea]

Not in this example

[Seanoskea]

Its a fairly low poly mesh. I’ve had this issue in 4 as well.

[ZacD]

Typical shadow bias issues. The solutions are either use more geometry, play with the shadow bias settings for the type of shadows you’re using, or play with other shadow settings, range, or shadow type like cascade vs vsm vs distance field shadows.