To keep uv maps simple for the script, instead of putting a ton of geometry on the same uv map. I split the object in many parts and assign a uv map for each part. It’s much faster to build lighting with a ton of small res lightmaps than a couple of high res ones. It’s even more true when you use the Swarm agent for distributed rendering in ue4.
Of course it’s not a viable workflow for game dev but for arch-viz it’s fine imo.