Microsoft HoloLens Developer???s Guide

Local coordinate systems

In all the code samples we have used previously, we always started out with a coordinate system in which the user is in the center of the world. At least, she is initially. Every item we place something somewhere, it is positioned relative to the user's position. As we have seen, this might lead to undesirable behavior. If we express the position of each object relative to the user, we are talking about one global coordinate system.

Another approach might be to have a local coordinate system for each object. Let us assume each object has its own coordinate system and that the center of that coordinate system - thus, position (0,0,0) - is at the heart of the hologram. If we do this, we can easily move objects about. ...