Arrrr . . . it’s been a while doing bunch of various stuff. Finally I got sth to share while scripting my autorig system.
Usually I don’t care about gimbal lock since I discovered the “euler filter” button in graph editor. And I always thought that better rotate order means cleaner animation curves only. Recently I found another case showing the importance of proper rotate order.
Imagine a standard 3-joint IK arm (say, left arm) with simple pole vector setup. When the character moves his arm ( ikHandle ) forward and about to the right, the upper arm joint’s rotation would pop from (0, -89.x, 0) to crazy values like (180, -89.x, -180). It took me a while to think about it . . .
A better rotate order seems to help.
Here is the best gimbal lock explanation I’ve seen https://www.youtube.com/watch?v=zc8b2Jo7mno.