Lightmap problem: overlapping UV

Dear Unreal Community,

We’re having problem when we try to build lightmap for statics that have overlapping UVs. In Unity, lightmap are generated on import but this seems like not an option for Unreal. So is there anyway to fix this problem without re-import with extra uv maps?
And if we indeed have to go generate our own UV for lightmap, how do we import it in correctly for Unreal?


  1. Go into the static mesh editor (double klick onto the mesh) - generate unique uvs - select the 2nd channel and click onto generate

When it still doesnt work, you will have to create a 2nd uv channel + lightmap in your 3d program

Spent a good amount of time trying to do what you suggested. We just couldn’t find this “generate unique uvs - select the 2nd channel and click onto generate” any where in the mesh window though. Can you help point us to where it is?

Really appreciate this in advance…

Never mide, we found it:
Static Mesh Editor > Window > Generate Unique UVs

We have another problem. After we generate a second UV, how do we tell the engine to use the second UV as our lightmap?

It should use it automatically, because when you dont have a 2nd uv channel, the UE4 uses the 1st one as a lightmap

I believe it’s not automated if you import mesh with single uv channel and then REimport mesh with 2 uv channels.


Dang it , you just made my day, Thx!

You are a lifesaver man!