@Override
    public Transform getWorldTransform(Transform t) {
        t.set(motionStateTrans);
        return t;
    }
Called from Bullet when creating the rigid body.
@param t caller-provided storage for the Transform
@return t
jme3-jbullet/src/main/java/com/jme3/bullet/objects/infos/RigidBodyMotionState.java