@Override
    protected void removeSpatialData(Spatial spat) {
        if (added) {
            removePhysics(space);
        }

        skeleton = null;

        boneLinks.clear();
        boneLinkList = null;
        torsoLink = null;
        transformer = null;
    }
Remove spatial-dependent data. Invoked each time this control is rebuilt
or removed from a spatial.

@param spat the previously controlled spatial (unused)
jme3-jbullet/src/main/java/com/jme3/bullet/animation/DacLinks.java