View Full Version : Still seeking help with IKspline
03-30-2009, 06:18 PM
Ok im on the verge of giving up with this now so any help would be great. Here is an image of a Bip head from side and top views:
As you can see i have added a Ik spline as a ponytail (i dont want to use the bip ponytails). The Image shows the result of turning the head. For some reason the parent spline bone doesnt follow it correctly and just sort of stays at the same angle it was originally. as you can imagine, this is producing some horrible looking results. Why is it doing this?
The top point helper is linked to the bip head. I have tried both link constraining (to head) and path constraining (to curve) the bone chain and results are the same.
I know that i can turn off rotations along the x in the IK hierarchy, but although it does the job that just makes the ponytail move into a strange undesirable position so its not really helping.
Again, thanks for any help anybody can offer.
03-30-2009, 07:12 PM
Have you tried posting this in the rigging forum.you might have better luck as there are some real gurus on the subject over there.(unless,of course,you're lucky enough and Pen spots it here):D
03-30-2009, 08:38 PM
good suggestion, ive just done so. im just amazed that this doesnt seem to be a problem anybody else has had, ive tried remaking it several times now and the result is always the same.
03-30-2009, 09:18 PM
I am not quite sure if I know exactly what you want, but I think the problem (as I understood it) lies with the Spline's Vertices being of the 'Bezier' type. Try 'Smooth' or 'Corner' (at least for the top Vertex).
03-30-2009, 10:08 PM
actually im not sure if you understood correctly. If you look at the image, the root/parent bone hasnt actually rotated with the turning of the head, its moved with it only. It still follows the curve but local along the x it hasnt rotated properly.
edit: Then again im not sure how you change a nurbs curve vertex to smooth so im not sure if your solution will fix it regardless.
03-30-2009, 10:23 PM
Can you post a picture of your Spline (without the bones hiding it)? Because I think the bones are in fact following correctly, but the Spine itself creates the curve.
03-31-2009, 01:46 AM
Yes the bones are following the spline correctly but along the local x its not rotating with the head properly. Its very hard to explain thats why i included the image.
Look particularly at the top view
the 1st image is standard pose of the head
the 2nd is of the head rotated almost 90 degrees to the left (or its own right).
Notice how the parent bone is parallel in both images. To be working correctly the parent bone should have also rotated 90 degrees along with the head (and the rest should follow with it), But it hasnt.
Edit: actually from looking at just the spline curve its impossible to see how its rotating along the x
03-31-2009, 08:47 AM
Ahh...now I see it. Sorry, I must have been blind yesterday...
Anyways, in the IK Properties you can define an upnode, which determines the up-direction via its local Coordinate System. Create a Helper, link it to the Head Bone and use it as Upnode. (Hope it works, since I can't try it right now...)
03-31-2009, 03:42 PM
For some reason i didnt work when i linked the helper to the bone, when i added it as an upnode later, the whole thing distorted horribly and the helper for some reason decided to unlink itself. Any idea why that would happen?
To solve it though instead of linking i tried a position constraint, and it seemed to do the trick, but i wish the link way would have worked. I have a feeling it would work better?
03-31-2009, 03:56 PM
actually i have another question, is it ok to use the top helper of the spline as the upnode?
04-01-2009, 01:25 PM
Still around Piflik?
04-01-2009, 01:54 PM
I don't think it is a problem to use the top helper of the spline, but I haven't tried it. Creating an independent helper offers more flexibility.
04-02-2009, 06:28 PM
cheers for getting back to me piflik.
I must have something weird going on though, it certainly doesnt work for me to do that. Still. the position constraint seemed to work. The only thing though is that it doesnt rotate with the bone, does that matter for an upnode?
So you dont have any idea why the linking wasnt working? ill see if i can get a pic for you of what exactly is happening.
04-02-2009, 06:28 PM
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