Unity Game Optimization - Third Edition

Avoiding Euler angles

Avoid using Euler angles for any kind of orientation behavior. Quaternions are designed to be much better for representing angles (the only downside is that they are more abstract and harder to visualize when debugging) and maintaining accuracy whenever there are changes, while also avoiding the dreaded gimbal lock. Using Euler angles for calculations could eventually lead to inaccuracies after there are a lot of rotation changes, which is incredibly likely since the user's viewpoint will change by tiny amounts many times per second in both VR and AR.

Gimbal lock is a problem that can occur with Euler angles. Since Euler angles represent orientation via three axes, and there are overlaps when one of these axes is rotated ...