Lightmap too large despite no static shadows set on foliage

Hey guys,

The log under Lighting Results states:
“InstancedFoliageActor_0 The total lightmap size for this InstancedStaticMeshComponent is large, consider reducing the component’s lightmap resolution or number of mesh instances in this component”
and the lightmap does not compute.

I know there is a gazillion threads about this warning/error but the funny thing is that none of my foliage has static shadows turned on.

It’s an archviz project. I don’t want to disable static lighting entirely because I need it for my building. So back to the foliage:

  • At least 95% is painted using the foliage painting tool.
  • All of it is set static but with Cast Static Shadows off
  • For trees and bushes Cast Dynamic Shadow is set to on, for patches of grass, it is set to off

Any ideas what could be causing this error?

I have also tried setting all of the foliage to Movable but it doesn’t help much. I’ve tested it on a cut-down version of the scene (to the point when the lighting builds) and it speeds up the building about 30%.
But should foliage even be set to Movable despite it’s not going anywhere? I thought that setting it to static would have some performance/optimization benefits.

See this, I think this is buggy.

Foliages in one landscape component can only have one lightmap(If you paint will foliage panel), which is not enough in most cases.

The best solusion should let foliage use landscape lightmaps, which should not be so difficult, and that is what the engine used in my project supports. Go do it, Unreal guys.