https://docs.unity3d.com/ScriptReference/SceneManagement.LoadSceneMode.Additive.html https://docs.unity3d.com/ScriptReference/SceneManagement.Loa... Sure , you

https://docs.unity3d.com/ScriptReference/SceneManagement.LoadSceneMode.Additive.html https://docs.unity3d.com/ScriptReference/SceneManagement.Loa... Sure , you can add more scenes . I've never done it to create terrain though. Another trick is to not destroy certain game objects on load.