Any animation software uses it. Even if you manually set up rotations of an object, like the camera, via xyz-rotations, as soon as you start animating them via

Any animation software uses it. Even if you manually set up rotations of an object, like the camera, via xyz-rotations, as soon as you start animating them via keyframes, the interpolation is done by using quaternions. Maya exposes them in their API, Blender, Unreal also do so, basically any system. While an animation system might not have had it in the beginning, it can be added later and all the benefits can be used, without doing any major changes to the system. You first transform the Euler rotation into a quaternion rotation, then do your work with them, like interpolating a rotation, and when you want to visualize this interpolation, you just calculate the Euler rotation for a given interpolation step and apply the xyz rotations to the object to visualize it. Unreal's API gives a good overview of the functionality quaternions offer: https://docs.unrealengine.com/4.27/en-US/API/Runtime/Core/Math/FQuat/ https://docs.unrealengine.com/4.27/en-US/API/Runtime/Core/Ma...