[nox101]

But not in it's animation data, at least not by default

You key euler angles, it lerps euler angles for animation values, it then generates a quaternion the given the current value of the euler angles. Same for Unreal AFAIK

[hamish_todd]

Where in the docs does it say that? Euler angle lerps, in the general case (eg none of the starts or ends are 0), look like complete shit.

You need the log quat representation. Exp( Tlog(q1/q0) ) q0

[nox101]

> When interpolating between two rotations, the interpolation can either be performed on the Quaternion values or on the Euler Angles values.

from: https://docs.unity3d.com/2023.3/Documentation/Manual/animedi...

The default is Euler values

[hamish_todd]

From that page: "When Euler Angles interpolation is used, Unity internally bakes the curves into the Quaternion representation used internally. This is similar to what happens when importing animation into Unity from external programs"