I am trying some stuff on Unreal Engine to make something approching games like Commandos series. But for now, I'm stuck with something I can't figure how it is done : How are building interior handled ?
Here's a screenshot to illustrate what I say :
When you enter a building, everything become black, except the building's interior. The interior is isolated, there is no "communication" between the interior and the exterior, and between linked interiors. For exemple if you shoot with a weapon and there is an enemy outside just behind the door, he can't hear you.
Sometimes biggest buildings are divided in many parts, and each floor are a different "section" that are isolated from each other (you have a transition and can't communicate between). Here is an image that explain it well : Commandos 2 interior
Teleport : I first thinked that you were teleported to a different portion of the map, or a different small map, but it is unlikely. If you look at a window, you are at the same time outside (you can see your character outside at the window) and inside (you character is leaning out the window). Teleport would cause many sync issue.
Section toggle : Then, I thinked that the interior is already handled in the exterior map, but completely hidden, and when you enter it, it "deactivate" the exterior by hidding everything outside and displaying interior. Again, this is unlikely since map are full 3D (you can rotate 360°) and exterior are 2D.
How can I create this kind of transition?
I've specified that I am on Unreal, but I'm more searching the theorical way rather than Unreal specifics.