Archive: https://archive.today/isnWI From the post: >>When putting 3D graphics on a screen, we need a way to express rotations of the geometry we’re rendering. To avoid the problems that come with storing rotations as axes & angles, we could use quaternions. However quaternions require that we think in 4 distinct spatial dimensions, something humans are notoriously bad at. Thankfully there is an alternative that some argue is far more elegant and simpler to understand: Rotors. Rotors come from an area of mathematics called geometric algebra. Over the past few years I’ve seen a steady increase in the number of people claiming we should bin quaternions entirely in 3D graphics and replace them with rotors. I know nothing about either so I figured I’d try out rotors. I struggled to find educational materials online that clicked well with how I think about these things though, so this post is my own explanation of rotors and the surrounding mathematical concepts. It’s written with the specific intention of implementing rotation for 3D graphics and is intended to be used partly as an educational text and partly as a reference page.