- Create a level sequence
- Add a cube to the sequence
- Add a key to the cube's transform on the first frame
- scrub forward a bit (e.g. 2 seconds)
- Set the cube's Y (pitch) rotation to 270 degrees
- Play back the sequence, notice it rotates from 0 to 270 not 0 to -90 degrees
- Right click on the transform section and enable Quaternion Interpolation in its properties
- Play back the sequence, notice it now rotations from 0 to -90 degrees
- Scrub halfway between the two keys, and add a key for all rotations by pressing the add key button, without changing any values
- Play back the sequence
The cube rotations from 0 to 270 again.
The path the cube rotated in would remain the same.