Hey , I saw your post in my thread but I’ll respond here so as to not clutter it up.
As you probably know, my workflow is essentially: Vectorworks -> Sketchup -> Unreal Engine 4. But Blender should be more than adequate so there’s no need to change if you don’t want to.
The reason your surfaces are going all funky when you build lighting is most likely because of bad light-mapping (or even non-existent light-mapping). To double check, go to the static mesh editor and have a look to see if you have at least 2 UV channels. If you do have 2, check what the 2nd channel looks like. If it’s blank, or you don’t even HAVE a 2nd UV channel, then you have no lightmap which is your culprit. By default, UE4 looks to the 2nd UV channel for lightmaps.
Example:
(In this example, 1st UV channel is blank which is okay. 2nd UV channel has the proper map which is what you need.)
I’m 99% sure you don’t have a lightmap at all. I remember my own geometry doing the same freaky thing when I first started out (which was caused by not having a lightmap)
In any case there’s a lightmap tutorial for Blender specifically for UE4 on Youtube here: ]()
That should help get the ball rolling.