Swivel IK issue in Max.

Andreas

I've got an IK chain on a leg, and its spazzing out big time between the keyframes whenever I keyframe anything. What causes it and whats the best way to fix it or at least work around it? (so far I've been going through every keyframe, but it really isn't such a good option. I still get problems).

nezach

Could be a few things really. Without more info it's hard to say what the issue is.

If you apply IK to bones that are absolutely straight you can get issues with the solver flipping around as it tries to figure out what angle to bend in. Make sure your joints have a slight bend in them in the desired direction.

Another thing is to make sure that the joints are plainer. I usually layout bones that will receive IK in an ortho view, then translate and rotate them into place. The IK solver likes things to be in a plane, so make sure your joints are rotated like a hinge, not a ball joint.

You can set target objects to rotate the solver plane in the motion panel. Use a shape or helper as a control null.