I don’t use max or revit but the general workflow is you’d model something, unwrap it for texturing and unwrap it again on a second “channel” (that’s what they’re called in blender). You would then export the model and import it to unreal engine. place it where you want, do some lighting and bake the results with a lightmass build. There is an option when you import an asset for UE4 to create a lightmap UV for you, but usually it’s not 100% how you want it to be. Proper lightmap UVs dedicate the space to the surfaces you will actually see in-game. You can control how detailed you want the lightmap to be from the mesh details (double-click on the asset).
If you want more details watch some webinars on this site, I’m currently watching this https://www.unrealengine.com/en-US/o…for-architects
It’s not the best as the presenter glosses over many details, but it gives you an idea of the general workflow.