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System's Spaces vs in-app mapping
It seems the system needs to know where you are located (spaces) that's why I don't really understand why my app needs to scan the room itself instead of just using the current system space.
A related question : Tutorials are all showing how to save the result of the mapping into your desktop computer (for later use in unity) but the end-user will not have Unity, why don't you add tutorials to save/load these mapping results from the Hololens device itself ???