Spine acting weird: A solution found?

[ruukki]

I gotta start suspecting my own IQ: I was all certain I would have a rig that I can carry around with no problems: I'd group my control icons each under their own null nodes and after that, parent them under another node which I'd then use for, you know, moving the rig from place to place. All's well otherwise, but again the back of the character twists when I rotate the main mover, groups or no groups. Without the spline Ik it always works - so what to do to stop the spline Ik messing up an otherwise OK rig?
I'm not going to worry anyone to look over my rig, all I'd like to know is a method for avoiding this. The books I have all go like: "do this, then do that, and then do this and that". It's fine to have a step-by-step book otherwise, but they seldom give out all the reasons for what happens.

So's nobody else starts suspecting my IQ: otherwise I can read the books. No-flip knee, Group based IK leg, automatically rotating wrist, no problem. Stretchy spine, no problem. Corrective blends, no problem. Whatchamacallit expressions, no problem. etc.

Thanks for any answer, anybody! (Even if you say I actually am daft and point out the simple solution I should have run into maybe 6 weeks ago.) I'd throw in my firstborn son but... well I have problem with that bit too.

[utpal]

hey, i wish i could help you. but, i don't know what you posted in your original querry. and your problem is not too clear from this post..
but, if your parenting is right, it should move properly. though, i've noticed spline ik flipping my joints at times...
one thing though. are you using a spine setup in which you use locators to polevector constrain ik handles to rotate them? maybe you could try moving the ik handles a little farther away from your spine....
or maybe some object which maybe constraining a joint in your spine is not parented under your main mover? so that when everything else moves that constraining object is not moving??
there are so many things that could be causing this.. try selecting all the joints in your spine and checking their input connections to make sure all those objects whose inputs are coming in are properly parented...
or, are you using one joint in the spine heirarchy to directly control the rotation of another joint? if so, then it is very important to make sure the local rotation axes of all the joints are exactly lined up. this too can cause flipping.
did you check your script editor to make sure there are no cycle warnings??

[ruukki]

Hi, and thanks for a good reply. In fact this morning I started suspecting something like this. So: every object that controls the joint in any way must be parented to the main mover... is it perhaps best to group them first?

Probably the books give this answer too, but there's no troubleshooting section in any of them, so it's kinda tedious to try and find it, with my 5-year-old's patience.

No cycle warnings, the constraints seem to be OK.

I'll try it with this and thanks - I'm sure this was the correct idea.

Edit: I tried the above and it seems I had misunderstood the idea. In short, everything that controls the IK spline is (and was already) parented under the main mover one way or another. All control objects that control the actual joints and/or IK handles stay zeroed out when I move the whole package. Just when I rotate, some of the spinal joints rotate as well.

[CGTalk Moderation]

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.