JibA? is working on SoyA, has integrated Cal3D there and has just finished exporting it from BlendeR, see BlenderToCal

From: Jiba 
Date: Tue Aug 5, 2003  3:39:42 AM Europe/Helsinki
To: bf-python@blender.org
Subject: Re: [Bf-python] Action name and Bone.getQuat()
Reply-To: bf-python@blender.org

>> Then, how is it possible to get the quaternion corresponding to the bone
>> rotation (in the armature, NOT from the Ipo !) ?
>Talking about the Armature module?  Well, Jordi added that one, but he's
>not around now, so I've been taking care of it, slowly learning about
>armatures / bones.
If what you want is the quaternion of the bone, it's in bone.quat, or
method bone.getQuat().  To get access to the bones, use
armature.getBones().

Actually, bone.quat returns only the part of rotation due to IPO, and not the part due to the armature. E.g., if no IPO are defined, bone.quat == [1.0, 0.0, 0.0, 0.0]?, whatever the rotation of the bone is.

According to Blender C source, only head, tail and roll are affected by the armature's bone rotation (see DNA_armature_types.h : 47, and armature.c). I'm currently diving into Blender's source, for finding how to rebuild the "rest state" 's quaternion from head and tail.

comments:

the new BlenderArmature in 2.40 --antont, Tue, 08 Nov 2005 18:26:29 +0200 reply
.. the cal3d export will be one good test for the new getters which are now in BlenderCVS