Lightmap resolutions and memory size

Thanks for the replies.

Regarding the meshes in question, in fact I still don’t know the final number of these large building meshes, maybe even more than 100, and I will use level streaming mostly because not all of them should be present at one time. Actually, each of these objects is a physically large building since it’s a whole building in one mesh. Think of it like if you are modelling an old Italian town for example and you have your traditional houses next to each other. Each house is a separate large mesh which you will enter and interact with. You may wonder why not each house is made into smaller parts, well. it’s much much easier for me to model/import/export this way and less time consuming. I model the whole wall/floor/ceiling model as a single mesh and then export it to UE4. Then I attach smaller models with smaller lightmaps (64, 128, 256, 512 px) on the main frame mesh such as window frames and doors, furniture, etc. However, I found since the main building mesh is large I am only getting good shading quality with the highest lightmap sizes. Even 2048 is not sufficient for most meshes. I even sometimes do cut a large mesh into 4 portions in 3ds max and give each of them the 4096 resolution in order to get the good shading result. This is my current work flow.

It seems I will definitely have to use level streaming. So, the purpose of my question was actually trying to know:

  • how large a playable area at one given time can be (means how many buildings a level can have) since this is limited to the system RAM at the time of lightmass building and video RAM at gameplay time.

I think I have to do some tests with these large meshes and see how far can I go.
Now if I start to hit the limits of my system, will level streaming solve my problem by allowing me to divide the world into separate playing areas and baking each separately? What if at a certain time in the game you should be able to view the whole town from above, will that work with streaming?