Can different LODs have different lightmap layouts?


I’m building LODs for a lot of models and sometimes it’s incredibly hard to keep the original lightmap layout from LOD0. So instead of that I’ve begun to unwrap the lightmap UVs for the different LODs separately and then just running them through iPackThat - this way the lightmap layout of the different LODs are not the same but it is much faster for me to work this way.

My question is will this work with baked lighting or will the engine use the same baked lighting for example for LOD1 that was produced for LOD0 and create shading artifacts (because the lightmap layouts are different)?

I hope that makes sense and thank you for your time reading this!

It should work, as long as you specify the right UV index (channel) for each LOD in the mesh settings. Either way I would recommend you test it yourself with a very basic mesh and different LODs

You can only have a single lightmap for your mesh. This is assigned in the Lightmap Coordinate index. The base LOD is used for the lightmap layout and then the Lightmap texture is applied to the lower LODs.

Typically this wouldn’t post a problem unless you have a drastically different lower LOD mesh like going from a Sphere for the base to a cube for the lower lod, since the geometry wouldn’t necessarily line up.


Thanks Tim for clearing it up

“Landscape Instanced meshes don’t yet support unique static lighting for each LOD, lighting on LOD 1+ may be incorrect” Is this all about lightmap uv and how to fix? I’m stuck in this, please help