When a car windshield shatters some of the pieces stay attached to each other and it appears to bend. I don't think Houdini's glue can do that. Same question would apply when breaking a brick wall, I'd like to see the mortar keeping some of the brick attached to some of the other bricks. Currently, once the brick is released from the glue it doesn't try to stay attached to anything. It's too much of boolean, on or off. I can imagine some of bricks/glass would try to stay attached or hang from weaker glue connections.

How does Houdini glue work? Can I visualize the glue? When I use glue does it create spring constraints between my objects?

Any suggestions?

Here is an idea, although I'm not exactly sure how I would go about setting it up…

You can constrain all of the pieces to a plane, and have that plane be deformed.

If you wanted certain pieces to fall off, you can delete the constraints randomly or when the velocity of the object reaches a threshold value.

Just a thought.