Stiff Joints With Ik

[charles-fernandez]

Ever build a skeleton for a character, bind it to your model, get set driven key set up for some deformers, get your skin weight painted just right. Then when your almost at the finish line you try and set up some IK for your legs and the friggin' knees won't bend? Arrrgh!

I just created the masterwork of my career thus far, a Zombie, with a skin layer, a bone layer, and a few set driven key blendshape muscles. I really don't wan't to have to take this whole thing apart to give it a fresh pair of legs.

I just want to run an RP solver from the Hip to the ankle and have the knee bend like it's supposed to. I got the limit info setup like a normal knee. I've tried using the set prefered angle tool as well, when I apply the IK, the joints just lock to whatever angle I set and they stick like it's one big bone, no bending, no flexing, nothing... I've been working on this thing for about a month off and on, and I'm really stressing... any ideas here?

[joojaa]

This is actualy the reason you test your bone structures working before you start binding. TOugh rebinding it is no bigiie. couls you post a picture of the bone structure and maybe the hiararchy too.

Thing is its normal not to limit the bones at all. Since the limit causes horribvle problems once you start to key stuff.

[charles-fernandez]

Nevermind... got everything sorted. Went all McGyver on the skeleton, it ain't pretty, but it works. Now, if I can just get some blendshape facial expressions setup... I'll pretty much be done.

[riskbreaker]

Uh oh... I've just had this happen to me too. The thing is, I've been animating with this rig for the past 3 months and never had a problem. I've had this happen in previous rigs too and I've even fixed it, it's just been so long that I've forgotten how. Crap.

If i find a solution I'll post it.

And two minutes later... I remember.

Select the knee joint, go to the Attribute Editor, and look under 'Joint'. Remove the degrees of freedom for the things that aren't rotating (for my instance, it was Rotate Y and Rotate Z). Set the 'Preferred Angle' for the one that is rotating to + or - 5, depending on how your joints are oriented. If that doesn't work, try setting Preferred Angle to 0. You might get lucky.
If all else fails, just start playing with all these settings until you fix your problem.

I think it's a hack, but that's what Maya's built off of, right?