Single-Chain IK Issue

[Anonymous]

Hello everyone! I've been trying to create a simple dragon rig so I can use one of my models for pose reference. Nearly done with it, but I'm having a problem rigging the right wing up. No matter what I do, the IK for the wrist won't hold the wing 'hand' in place. The left side works perfectly and I've check, double-checked, triple-checked, and I had everything set up the same way. Even so the IK behaves differently and doesn't rotate the bones properly.

So, for example, if I move the chest around at all, the right wing will rotate along with it.

I've tried 'mirror joints' to make the right wing from the left (same issue). Tried using duplicate special to make the right wing (still the same problem). I can't find anything else that'd affect the IK, there's no incoming connections from anything. Tried re-orienting the joints a million times and I just end up with the 'this joint had non-zero rotations' error.

 I can't figure it out at all! It's driving me nuts! 

[Roland.Reyer]

Hi,

what is it that affects the fingers? (they're pink)

Can it be that the finger expression/rig still refers to the opposite side?

[Anonymous]

I just double checked everything, the only thing attached is the single chain IK

[kirbysteele · Accepted solution]

hey brightcat,

I suspect that it is a joint orient problem, but I have a quick fix that you could use instead of going through that process. 

If you create a duplicate shoulder, elbow and wrist joint in the exact position of the problem wing and then put an IK chain on that, you can then do parent constraints from the problem wing joints to the new IK joints. Just make sure to have the maintain offset option checked before constraining the problem joints and they should stay in the right place. Just make sure to attach the controlling joints into the clavicle or spine so that they will follow the rest of the skeleton when it moves.

On a side note, in general this is a nice way to create rigs for legs, arms, spines or even wings. Having a single hierarchy of joints that you can use for skinning which are controlled by copied joint chains that have all the complicated rigging on them can help avoid reskinning if there is a problem with controls or functionality. Also you can easily switch between influences like a IK arm and an FK arm since you can parent constraint to multiple sets of joints.

Hope this helps,

Kirby

[Anonymous]

I did as you said and now it works perfectly! Thank you! I will definitely keep this in mind for future rigs. I had no probs with duplicating the legs, their IKs work properly, so I didn't know what the heck went wrong.