protected void ensurePositiveVolumeBBox() {
        if (getModelBound() instanceof BoundingBox) {
            if (((BoundingBox)getModelBound()).getYExtent() < 0.001f) {
                // a correction so the box always has a volume
                ((BoundingBox)getModelBound()).setYExtent(0.001f);
                updateWorldBound();
            }
        }
    }
Called internally by com.jme3.util.clone.Cloner.  Do not call directly.
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/TerrainPatch.java