The real "a-ha" demystifying moment for me was not so much learning about the elementary rotation, translation or even perspective projection operations. It was

The real "a-ha" demystifying moment for me was not so much learning about the elementary rotation, translation or even perspective projection operations. It was understanding how all of those operations can be composed together into a single transformation and that all that 3D graphics really is, is transforming coordinates from one relative space to another. One important revelation in that regard for instance, was that moving a camera within a world is mathematically exactly the same as moving the world in the opposite direction relative to the camera. Once you get a feel for how transformations and coordinate spaces work, you can start playing around with them and a whole new world of possibilities opens up to you.