I"ve tried
var mtxZero:Matrix3D = new Matrix3D(joints[0].inverseBindPose.concat());
var mtxRoot:Matrix3D = new Matrix3D(joints[1].inverseBindPose.concat());
var mtxNeck:Matrix3D = new Matrix3D(joints[2].inverseBindPose.concat());
/*mtxRoot.invert();
mtxNeck.invert();
mtxHead.invert();
//mtxRoot * mtxHead * mtxNeck
mtxZero.append(mtxRoot)
mtxZero.append(mtxNeck);
mtxZero.invert();
comparing to Away3D builder property window joint neck has different matrix.
Thx
