In the past chapters, we mentioned transformations between coordinate spaces multiple times, but we deferred a more detailed explanation until this chapter.
As mentioned in the first chapter, you can theoretically choose what coordinate space each of your calculations is going to live in. In the case of real-time rendering, most of the choices have already been made for you by the graphics pipeline. It expects values (vertex positions, normals, etc.) to be in a certain coordinate space, at certain steps of the process.
One example ...
