Force LOD1 foliage to use LOD0 lightmaps?

Just came across this bug Unreal Engine Issues and Bug Tracker (UE-32299) after UE4 told me that lightmaps may look incorrect on LOD1 foliage, after building lighting:

Instanced meshes don’t yet support unique static lighting for each LOD, lighting on LOD1+ may be incorrect

I have foliage in my project that uses the same lightmap UVs for LOD0 and LOD1, and the language in that editor message and in the bug report imply that LOD1 meshes will just use the LOD0 lightmaps, which would be perfect for me, but it seems like no lighting at all has been built for LOD1, and the meshes are black.

Is the wording “may be incorrect” just a formality, and it’s actually impossible to have statically lit LOD1 meshes? Lightmap settings for LOD0 and LOD1 meshes are set up in the exact same way in my project, and the lightmap UVs cover the exact same space.

Hi mechanicalsnowman,

It was always intended to share the lightmaps across LODs provided they have the same UV mapping, but 4.14 seems to have introduced a bug where we were no longer sharing.

This has just been fixed for 4,15 and it should work provided the lightmap UV mappings are the same for all LODs. The warning is still there (slightly re-worded). For 4.16 it should be able to detect if the UV mappings are completely overlapping and omit the warning if the UVs are correct.


That’s great news, thank you very much Jack

Looking forward to switching over to 4.15!

Hi Jack,

For some reason we have to use 4.14.
Is there any solution to figure out?


But in 4.17.1 i’m still getting this message and can’t build lighting