@Override
    protected void controlUpdate(float tpf) {
        body.getBodyA().getPhysicsLocation(a.getTranslation());
        body.getBodyA().getPhysicsRotation(a.getRotation());

        body.getBodyB().getPhysicsLocation(b.getTranslation());
        body.getBodyB().getPhysicsRotation(b.getRotation());

        geomA.setLocalTransform(a);
        geomB.setLocalTransform(b);

        arrowA.setArrowExtent(body.getPivotA());
        arrowB.setArrowExtent(body.getPivotB());
    }
Update this control. Invoked once per frame during the logical-state
update, provided the control is enabled and added to a scene. Should be
invoked only by a subclass or by AbstractControl.

@param tpf the time interval between frames (in seconds, &ge;0)
jme3-jbullet/src/main/java/com/jme3/bullet/debug/BulletJointDebugControl.java