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I am trying to save bone joints to a file, and am using this format. I was wondering if anyone could clear up a few questions I have

  1. why do I need to provide rotation data for the bone, if I already gave it the location?
  2. How do I calculate the rotation of each axis if I have the relative location from the parent joint?

** EDIT **

After doing some more digging, I think that it has something to do with quaternions, so, could someone point me to a good resource on using quaternions for bone joints?


I think I've solved it, but I don't understand how it works. I can't seem to find any google results explaining it. I'd appreciate if anyone could send resources explaining it to me.

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A complete answer for this question means writing a chapter. Google these terms: skinning, md5 model, bones, skeleton, blending. You need to understand some concepts: hierarchical transformations, bone matrices, pose of an object, orientation quaternion, vertex blending/skinning. Try to understand what a hierarchical transform (parenting) system is first, then post your questions here. – teodron Sep 3 '12 at 15:29
Can you point out the question please? – Maik Semder Nov 2 '12 at 16:28
I guess now that I've done some more research, the question at the time I was posting would have best been "Where is there a good guide on how to use bone joints" – raser Nov 6 '12 at 17:22

I'll tell you what I know about quaternions so far as I'm now attempting my own 3d animation. A quaternion is a combination of a Vector and a Scaler. A Vector are real number components that can represent direction distance or,velocity(i.e. (x,y,z)). A Scaler is a magnitude(distance/length) without an angle. with these you can calculate what you need to know about a particular bones capabilities like rotation and distance.

(I could be wrong on multiple levels.)

Message me at if you wanna team up.

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