In the previous chapter, we took a look at how HoloLens spatial mapping works. This is the way the machine learns about its environment. It is important for a couple of reasons. Firstly, if we want to have a great mixed-reality experience, the holograms need to know where things are. Secondly, we need information about the real-world surface to help the user. We talked about different scenarios where, for instance, the user needs to place something in the world, or where we need to guide the user to a certain place in her room.
There is one more thing knowing about the physical layout of the world, and that is what this chapter will be about.
