Rotation order for Human Wrist

#1

Hi ,

I setup a Human “Wrist” rig .
Forearm twist with rotate of wrist controler.

wrist controler :

X axis = twist
Y axis = side to side
Z axis = forward and backward

I have problem with Gimbal Lock and Rotation order.
What is true Rotation order for Human Wrist?

Thanks.

#2

Humans don’t have rotation orders. We don’t gimbal lock.

But, here’s a start: think about what you do least with your wrist, and the limits of each “axis”.

The wrist predominantly rotates forward and backward (your Z).
The wrist also twists quite a bit (your X).
The wrist can only rotate a little side to side (your Y).

#3

I agree with royg. I would go a step further and say with regards to the human wrist, the twist should be evaluated last. Look at how your wrist moves. Yes, forwards and backwards and side to side, but can you twist your hand on its own axis when it’s bent forward? Or tilted sideways? No, the twist action causes your hand to swing about the forearm when it’s bent or tilted. That means that the twist axis should not be the ‘child’ of any other rotation and remain oriented with the forearm.

Z - forwards/backwards
Y - side to side
X - twist

ZYX should be your best choice.

#4

Thanks . But in some poses two axis overlap together. such as in below image wrist can’t rotate side by side.

#5

I said ZYX.
Sorry if my post was confusing, but I didn’t exactly agree with royg. I agreed with his statements about the wrist’s movement, but my rotation order suggestion was different. Your image shows me that you didn’t try my suggestion as it is impossible for Z and Y to align like that with ZYX. Gimbal lock will only occur with the first and last rotation axes. Only Z and X can align to one another with ZYX.

#6

Thanks gonzalimator. very appreciate.
I want test it.

#7

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