View Full Version : Forearm twist on IK arm?

06 June 2011, 05:51 PM
What I have at the moment is an IKFK arm setup, and I have the twist on the FK chain, but on the IK chain, when I move the arm control the forearm twist snaps back to its original orientation. Is this normal for the setup? Or am I doing something wrong? Thanks for any help.

06 June 2011, 05:54 PM
I forgot to mention, there are 4 joints down the chain shoulder, elbow, forearm, wrist. Working in Maya 2011 as well if that makes a difference.

06 June 2011, 01:43 AM
Have the twist joint independent of the FK/Ik jnt. Feed in the FK or IK (anyone) shld jnt value through a blender(utility node) to the Twist jnt. Also u can distribute the twist down the twist chain depending on the no. of twist jnt through Multiply divide (utility node) and divding with the no. of twist jnt.

07 July 2011, 05:18 AM
Ok, the thing is if you are going to connect the rotation to the twist joint, you are gonna encounter flipping as a result of so called GIMBAL LOCK! I suggest you to use the power of aim constraint with up vector. Or, you could create a joint chain; setup a spline IK and use advance twist controlled via object Up (Start End).

Cactus Dan
07 July 2011, 04:14 PM

I agree with Boucha. I always use aim/up vector constraints for forearm twist. ;)

Cactus Dan

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07 July 2011, 04:15 PM
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