View Full Version : IK-Spline Spine ( Shoulders independent Motion )

07 July 2005, 04:24 PM
Hi Guys,

Hope you can help me out here. I'm busting my chops trying to solve this one.

I've followed the Jason Schiefler method of rigging the back with Spline IK. Got everything rolling nice. Nice twisting, bending etc.

But now I'd like totally independent motion on the shoulders, which I'm not getting. The hips stay fixed when i rotate the shoulders, but when i rotate the hips, i get a bit of motion up in the shoulders.

I've looked at Jason's spine rig and even his has some motion going on in the shoulders when u rotate the hips around. Then I looked to the TSM ( the setup machine )'s setup and they've got a beautifully stationary shoulder.

I wonder how abouts you guys achieve that?

I've got a spline curve with 5 cv's on it, for each cv i created a cluster handle.

Some info on my spine :

the first 2 clusters I parented to the Hip Ctrl , and the last 2 I parented to the Shoulder Ctrl. The one in the middle, I didn't know what to do with, so I tried parenting it to the Shoulder Ctrl also. ....

Thanks in advance for your advise! Hope to hear from y'all soon.



07 July 2005, 07:54 AM
I can not give you exact info how I solved that problem ( it`s been a while), but if I remember correctly I put another transform in there for the neck and parentConstrained it to the shoulder manipulator/cluster. Works great and the kids love it too : )

07 July 2005, 07:52 PM
Also, take a look at the advanced twist controls on the IK spline handle. This is a more recent addition to Maya than Jason's setup, so you may be able to simplify things to twist the shoulders and hips separately.

07 July 2005, 03:14 PM
For a tutorial on advanced twist controls, check out

07 July 2005, 09:16 PM
i've been looking into this recently- i really like the schleiffer spine but don't like that aspect of it. i recently did a set up with a 2 skeleton rig where the bind bones are constrained to the ik spine. basically what i did was taper off the influence of the top joints onto another set of control objects point and orient constrained to one of the spine bones. This way the influence feathers out when it gets to the top. it gets complicated though and isn't that elegant solution, as it works fine if the shoulders don't inherit the spine motion at all, but once you do, say, a flip, you need a non-detached hierarchy, which then requires a bit of mel to snap parent spaces without hitching.

curious to see other people's solutions. I like the functionality of FinalRig at in this regard, but there's always a tradeoff

CGTalk Moderation
07 July 2005, 09:16 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.