Hello

My character's animation need a lot flip motion, like turning head back and forth (or turning torso back and forth without head), and there are many slots(eyes, brows, mouth...) and bones(hair parts, helmet...) as head bone's children,

I think the best way to turn the head is "FLIP function of bone", because i do not need to setup extra images for the other side, and i just need keying the "flip" property when animating .

I know there already has a topic discussing about this http://zh.esotericsoftware.com/forum/viewtopic.php?f=11&t=625, and Nate said

This flipping uses the world axes, not the bone's local axes, because it simplifies the work/math that needs to be done to update the world transform for bones.

But if flip with world axis, i will get the result like this...

After flipping the bone, my bone did not match original pose... i need to rotate manually to match the pose, and adjust rotation curve to stepped to prevent odd rotating motion.

But, If the flip function of bone can work with local axis, will be a very efficient way to solve this situation!!

( flip with local axis with remain the same pose )

I hope it will be a feature in the future! Thanks!
Spine is really a great software!

(And sorry for my poor English)