Ik handle disadvantage
 

hello to all,

does anybody know if it is possible to use an IK handle on an arm and also achieve a bicep twist from a joint between the shoulder and the elbow. When the the Ik handle is applied the bicep twist bone is disabled for a controlable FK twist.

Does anybody know any solution to this?

Matt

You could probably use the same method we use with knee orientation. Pole Vector constrain the IK handle to a locator.

Re: Ik handle disadvantage
 

a bicept twist...?? bicept muscles do not twist, hence a bicept muscle would not need to be twisted as well. i don' t know excactly what u are trying to acheive, but the bicept joint is there purely for deformation purposes. since the shoulder bone is a ball joint (it rotatates in all axis) and the elbow is a hinge joint (rotates in one axis) the bicept joint is there to maintain volume when these 2 joints are manipulated. kinda like why u need a forearm joint between the wrist and the elbow. the wrist is a ball joint and and the elbow a hinge joint.

bicep twist was probably the wrong term. I just want a joint that twists below the shoulder as in fact when the shoulder twists the skin aroud the shoulder hardly moves at all. The movement mostly occurs further down and this joint is for these purposes. I am not looking for any realistic deformations in terms of muscles.

if all the rotations come from the shoulder skin weighting becomes complecated and the extra joint would make things both simpler and more like actual movement, though that doesnt really exist.

check out www.cane-toad.com/tuteRig_Shoulder.htm


I find the wrist is not simply a ball joint. The twist in the wrist comes from the two forearm bones rotaing around each other which is more complex than a wrist ball joint. This is simplified in maya by adding a joint in the forearm which can be used for twisting of the wrist.

I tend to use FK for the arms.