Question about Quaternions (Global Settings)

[Jasper29]

Hey guys, quick question: I was looking through Global Settings recently and saw the option under ‘Rigging’ to select quaternions for ball and socket joints. I understand a decent amount about quaternions during animation (gimbal-lock, in between framing, etc), but I’m curious what exactly does this setting do though? It’s under rigging so it obviously must be for setting up the rigs, but during rig creation, bones are setup using euler. When animating with an IK rig, the IK drives the armature and quaternions will solve the positioning of those bones. So what does turning this option on/off during import actually do?

[Thomas Larsson]

It's the thigh and upper arm (bend) bones that become quaternions.

[Jasper29]

Ah, I see, makes sense. Sorry I was overthinking it--been a long day. Thank you for specifying Thomas