Lightmap Resolution Problems

Hello, hoping someone might have some insight on this: I made a few prefabs in blender to quickly populate my levels in unreal. I optimized and set up the UV mapping for each prefab. I imported them into the engine, but then get some pretty harsh lightmap shadows. Increasing the lightmap resolution of each prefab instantly cleans everything up, but when I rebuild the lighting all the shadows come back again. Any advice is appreciated!

Is each wall one mesh?

Those wall sections are several different meshes. I just made some planes to show the issue. The shadow changes between each new mesh. I was hoping to make larger/longer prefabs of wall sections with the crown molding, door frames, inside and outside corners, etc. I assume I will still run into this problem at the seams.

I’m not a lighting expert, but I do know you need to have one mesh if you want no seams. So one mesh for each wall I’m afriad.

Thank you for your response. I understand. I was able to solve some seam issues by disabling the ‘cast shadow’ option on the wall meshes. However, the results were not consistent across the whole scene, even though the models are the same.

Lightmap calculation is made separately for each mesh composing your wall. That’s the cause of your problem. Light stops at each mesh edge bascially. So If you want a single nice looking continuous lightmap, you should stitch all those walls together. It’s the easiest way. You should not always go modular when it’s not necessary.