So here I have these walls that I want Unreal to create the lightmaps for.
Should I leave the UV Shells detached from each other as much as possible, or should I Stitch / Weld them together like I did with the 2 shells in the second image?
In the context of this model, it is better to have them detached. Also, note, that your UV layout seems to have insufficient space between UV shells at first glance.
Yeah that’s because I will let Unreal make the lightmap uv layout. Thanks for your help!