code: public void     getWorldPosition(int boneindex, Vector3f pos) 
      {
          Bone bone = mBones[boneindex];
          int boneParent = mSkeleton.getParentBoneIndex(boneindex);
  
          if ((boneParent >= 0) && ((bone.Changed & LOCAL_ROT) == LOCAL_ROT))
          {
              calcWorld(bone, boneParent);
          }
          pos.x = bone.WorldMatrix.m30();
          pos.y = bone.WorldMatrix.m31();
          pos.z = bone.WorldMatrix.m32();
      }
docs: Get the world position of the given bone (relative to skeleton root).
  <p>
  All bones in the skeleton start out at the origin oriented along the bone axis (usually 0,0,1).
  The pose orients and positions each bone in the skeleton with respect to this initial state.
  The world bone matrix expresses the orientation and position of the bone relative
  to the root of the skeleton. This function gets the world space position of the designated bone.
  @param boneindex index of bone whose position is wanted.
  @return world position for the given bone.
  
  @see #setWorldPositions