Precalc light banding issues on FBX files

Hello all!

So I’m experimenting with Unreal Engine 4 with SDK level construction from FBX tile assets, and have noticed some lighting weirdness with precalculated lights that I can’t figure out. Probably something stupid I’m doing but:


These are literally just two poly quads exported with UV maps as FBX files (0,0 to 1,1 for UVs, tried 2 channels too), and once imported I’ve studied in the model viewer and as far as I can tell the polys, normals and tangents all look correct so am lead to believe this isn’t an FBX import issue. And with the dynamic lights (if I disable precalc in world properties) look fine. However whenever I bake the lights (production quality) I end up with seams in the lighting across different FBX instances, the lighting being disjointed as you can see in the above screenshot. The static models are correctly tiled within unreal. I was wondering how I can resolve this and get smooth lighting with static meshes, or where I could look for the issue. In the Reflection Subway example the walls are made from segments in a not dissimilar way so I can only assume there is something amiss here or something I’m failing to set up somewhere.

If anyone needs any more info I will gladly provide,

thanks in advance!