public Vector3f getExtent(Vector3f store) {
        if (store == null) {
            store = new Vector3f();
        }
        store.set(xExtent, yExtent, zExtent);
        return store;
    }
Query extent.

@param store
           where extent gets stored - null to return a new vector
@return store / new vector
jme3-core/src/main/java/com/jme3/bounding/BoundingBox.java