Static mesh created from BSP has missing faces in lighting

[Shy_Snake_Games]

I’m at a loss as to why the meshes that appear correctly in Blender and in the Mesh Editor have missing faces when I switch to “Show lighting only” view. The shadows also look wonky (stripy, while the face is supposed to be smooth).

I have created these static meshes from BSPs in UE editor. I have set the Lightmap index to 1 for the ones that Unreal created initially. This fixed the original wrapping UVs error, but did nothing for the shadows.

The mesh in the screen shots I have exported to Blender, re-created a UV map and reimported it, assigning the correct Lightmap index.That also didn’t fix the issue.

Anyone have any ideas as to what is missing?
Thanks!

[Shy_Snake_Games]

BTW, this happens even with the simplest of BSPs, such as a cube, as soon as it’s converted to a mesh.

[Shy_Snake_Games]

I believe I’ve been able to understand the reason for this behaviour. It is caused by materials from the “Real Surfaces” packs 1 and 2.

My understanding is that the material tesselates the surfaces and applies a displacement map, and this only shows up in “Lit” view, but not in the “Lighting only” view. Once I apply simpler materials to the surfaces of the mesh, they show up just fine.

The lighting appears to build without issues with these materials, it’s only a problem when using “Lighting only” view.