I think you’re kind of between a rock and a hard place there.
If you want to be able to load maps while still in another level, then you’re probably looking at level streaming ( which is out because it doesn’t work with world partition ), or level instances.
You can use instances, but you’re going to get conflicting lighting, so it’s better to have all the lighting in one ( otherwise empty ) main level. I’m only talking about the main actors here ( directional light, skylight, fog etc ).
The other problem with using level instances is, you’ll need to load the new instance away from the sandbox area, otherwise they will just overlap. Then, move the player and unload the sandbox.
You can load partitioned maps as an instance.
This is the setup
- Always loaded main level with only lighting
- Load instance of Map1 and put the player in it
when they want to change level
- Load instance of Sandbox and move the player
- Unload Map1
- Load Map2 and move the player
- Unload Sandbox
Like that
