How would light baking work in regards to modular levels?

I’ll try and describe a really simple example here,

I have a lovely detailed wall piece that I’ve created and want to use multiple times in the level. This piece shouldn’t have it’s own light map because it’s being repeated? For example in another area there may be a statue casting a shadow on one of them. So then how do people lightmap modular levels within Unreal? All I can think of is to create the full level in a 3D application and divide it up into chunks with their own lightmaps.

Every mesh has his own lightmap after building the light… so far i know there is no sharing of one light map for multiple meshes even when it is the same…

oOOOh right. So even if two wall pieces have the same UV2 (or 1 in the case of Unreal) for the LM, when you bake lights it takes both UVs and places them into one lightmap automatically?

Every mesh has it’s own lightmap, for example i have 6 balks in my scene “they are all the same” but i placed them in different places, of course they all have they’re own lightmap baked…
I’m not sure why you are asking ? simply place your mesh whereevery you need it and build the light…

Each static mesh gets its own lightmap, by reusing a mesh, it saves on memory for the actual mesh, not the lightmaps. It would then only keep one copy of the mesh in memory, but it would still have a lightmap for every time that mesh is used.