Lightmap on Large mesh

Hi Guys! I didnt find anything about this, i was trying to solve on my own, but seams that im thinking on the wrong way.

So, thats my Mesh attached.
The whole mesh contains 6 materials on unreal, worked fine. But when i generated the UV channel 2 for lightmaping i organized by material, not by mesh. Can work that way? Could i apply a lightmap from external renderer software? OR even AO maps.

So, i created 6 uv channels because the mesh contains 6 materials. I was thinking about puttin the “lightmap” on the material and disable on the unreal. Can that be possible?

The question is, should i make this modular, make a pice for the floor, the walls, the seats individually? The chrome posts.

Thanks guys! Im new at the forum, that sounds clear?

You should not make that all one mesh, but make one bench and place it multiple times, same for anything else.
Think of ue4 as lego’s, using the same object over to get the result you need.
So yes, make this mesh modular.
This also results in each mesh having its own uv map and uv lightmap which makes it easier to give each mesh a proper sized lightmap.

Its highly recommended that a mesh should not have more than 3 uv’s (for optimisation sake) sure you can have more but in most cases it can be avoided.

Also, if a mesh has 6 materials attached to it, it means the mesh needs to be redrawn by your gpu 6 times, which isnt very optimal. It would be better to make one material per mesh. (or even better, one master material and instance that for different meshes)

You could “bake” in the shadows in the diffuse map and disable the mesh getting lighting (or using dynamic light) but if you move the lights in your environment or have a dynamic light it would mean you need to change the shadow parts of your diffuse.