I have two sublevels inside a master level. The two sublevels have wildly different lighting (both are exteriors). Each has its own skylight. I can build lighting with no problems when the levels are open by themselves, but when I open them in the master level, the lighting information seems to be lost. When I build lighting in the master level, I get the error: Multiple sky lights are active, only one can be enabled per world.
Does that imply that I should be using multiple worlds? And if so, how does one go about doing that? I can’t find any mention of multiple worlds anywhere in the documentation.
I have discovered that if you do not stream the sub-levels, but instead choose “Always Loaded” from the “Change Streaming Method” submenu, that the lighting baked when the levels are opened individually is preserved. So it looks to me like this is a bug with blueprint level streaming.
When testing in “Standalone Game” mode or Launch → MyComputer, it still looks like PIE with Blueprint Streaming mode. So the only thing that looks correct so far is Always Loaded with Play-in-Editor.
Stationary sky lights are implemented in a way such that there can only be one of them active at a time. Changing the streaming method is probably switching which one gets used, it depends on the load order.
I can build lighting with no problems when the levels are open by themselves, but when I open them in the master level, the lighting information seems to be lost.
This is not really supported with partially static lighting methods (aka any stationary light). The lighting part is applied dynamically and things like sky light and directional lights affect the whole scene. If you used static lights it could work, however note that static Sky Light is not supported yet in 4.1, but will be in 4.2.
We got around this by using Global Post Process ambient cubemaps and not having any two scenes visible at the same time. It works for us. It would have been easier to do blocking loads but we are making a “guided tour” which has specific timings that occur throughout the experience, controlled by a matinee in the persistent level, and blocking level loads would have made us change our whole approach.
You can bake them separately, in separate levels. Don’t bake the master level. I’m still doing it that way. You can also now use static skylights as mentioned above.
