Splotchy landscape shadows solution.

I was having trouble with landscape shadows producing weirdness like this.

I spent 3 days trying every solution I could find here on the forums or answerhub.
Finally I discovered that the problem almost completely went away when the material was set to two sided.

There were still a few splotches here and there, it got even better after setting 2 sided lighting on the lightmass settings.

Just figured I would post here in case anyone else was going mad with the same issue.

This is usually caused when the edge of the landscape has no backside. If you are using all static lights this will be no problem but for dynamic shadowing there can be a cost to doing that. In that case it can be better to make a flat lip around the landscape so there are faces to shadow when the light is at a steep angle.


I went around the landscape and made a flat lip… It helped a bit. But not enough.
I do have a couple landscape holes, but they are blocked with static meshes so there should not be any light going through the hole.

For some reason having a double sided material seems to be the best work around for now.

Just a quick update on this.

Setting the material to double sided, then building the lighting, then resetting the material to single sided eliminates the splotches and the additional cost of having a double sided material…
Don’t know why I didn’t think of that earlier!