View Full Version : difference between Twist and Roll on ikSplineHandle

03 March 2004, 12:53 PM
I'm building a spine Rig right now. Offcourse i do it with a splineIK.
And now my question is: Can i use the Roll atribute instead of the Twis attribute, or has this some strange effects on my rig ?

I ask this because when i use the Twist attribute, the bones will flip when i translate the hip control. And when i use the Roll atribute then all seems to mover and rotate correctly.

My back is build according to Jason Schleifer's FK/IK Back Solution.

:: Galactor ::

03 March 2004, 02:39 AM
The difference is that instead of all the joint in the splike rotating evenly they need to rotate les and less as you go down the spine to create smooth deformation. The difference between the twist and roll channels is the twist channel has a falloff when rotating the joints, whereas the roll channel rotates all the joints evenly. To fix this, set driven keys on the roll channels of the spline IK for the back, hips, and neck.

Parenting the spline IK constrained skeletons under the Head box will fix the problem of the spline going nuts when the head turns. Hope this helps.......but this is how the righ I'm working on works so if your hierarchy is completely different Im not sure I can help.

03 March 2004, 12:35 PM
yes, i see it now. Thanks

:: Galactor ::

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