Ik handle disadvantage

# 1 12-07-2004 , 07:51 AM

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Join Date: Jan 2004

Posts: 40

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

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# 2 12-07-2004 , 12:49 PM

The Maya Mountain
Join Date: Aug 2002

Location: Seattle, WA

Posts: 8,245

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

-Mike
The Maya Toolbelt

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# 3 12-07-2004 , 05:06 PM

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Join Date: Jun 2003

Location: stuck in the 90's boston, USA

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Re: Ik handle disadvantage

Originally posted by matmonkfish
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

Originally Posted by

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.

Image dump

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# 4 12-07-2004 , 05:35 PM

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Join Date: Jan 2004

Posts: 40

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.

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