How do I bake lighting for individual levels using the same directional light in the persistent level?

I currently have a setup with a couple of streamed levels (Lets call them ‘Level001’ and ‘Level002’) and a Persistent map with a stationary Directional light as my sun. The levels are all located at the centre of the world, one on top of the other.

I want to be able to build the lighting on each of the streamed levels using the Directional light from persistent, but without the content from Level001 casting shadows onto Level002 and vice versa.

While long winded, in UDK I was able to switch off Level002’s visibility, bake Level001’s lighting, then do the same for Level002. In UE4, it initially looks like it’s going to be the same, but after finishing the bake, it seems to have switched all my levels back and cast shadows onto everything. This may be a bug however, as the visibility toggle is still set to ‘off’ despite everything in the editor being visible.

I am able to do it by having a directional light in each streamed level, however that means I have to have 1 sun per level, rather than a single sun that I can use across all levels.

I think there may be a bug when building lighting across levels in a persistent map…if I ‘hide’ certain maps and build lighting, I get a message saying these hidden levels won’t be included in the bake. This is fine, as that’s what I want to do. However, if I select continue, it builds all lighting for all maps anyway…

My workaround solution is to keep my static ‘sun’ light in its own map, which is included in the persistent along with the streamed levels. If I then open each of these levels individually (i.e. not in persistent) and stream the ‘sun’ map into this and build, it seems to work fine. I just need to be careful not to build lighting in the actual persistent, else I’ll have to rebake all the levels individually again.

It’s all a bit long winded, but it works.

What would be nice is the option to build lighting from within the persistent level, but ensure that each level is built ‘individually’, i.e. Level001’s geometry doesn’t cast shadows on Level002’s geometry, and so on. Just an overall checkbox maybe, or the ability to flag streamed levels to build independently from each other. :slight_smile:

I hope they will adding such a function to build lightning from the persistent level to all sub levels. Because currently it’s building lightning but still not very smooth, it still gives me the error “lightning needs to be rebuilt (909 unbuilts object(s))”.

really great information thanks, But how do you stream persistent level which have your sun to the sublevel ?