private static CompoundCollisionShape createBoxCompoundShape(Node rootNode) {
        return createCompoundShape(rootNode, new CompoundCollisionShape(), false);
    }
This type of collision shape creates a CompoundShape made out of boxes
that are based on the bounds of the Geometries in the tree.

@param rootNode the node on which to base the shape (not null)
@return a new shape (not null)
jme3-jbullet/src/main/java/com/jme3/bullet/util/CollisionShapeFactory.java