New answers tagged scene
Look at Application.LoadLevelAdditive, you can load the scene in parts. A good idea might be to disable whole sections of the scene that you are not in. For example group the whole scene in one parent gameobject and disable that, or perhaps use a tag for this. You could also use layers, but they're a bit tricky.
If you don't want to use separate levels, you will need to put all of your logic on the same "level" but in different places (within the scene). Then move the camera so that only the things you want to see are visible.
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