I want to have an interaction between a flip fluid simulation and RBD's. My goal is to fracture a falling active RBD on collision with the fluid. Additionally I want to use a dynamic constraining to keep some parts together and some not. I think the “RBD Glue Object”-DOP could work, but it doesn't. A “RBD Fracture Object” DOP is working, but it's fracturing the parts instantly after the collision.

I attached a simple setup. The interaction between flip fluid and the two RBD boxes is working generally. The RBD is colliding and floating after a moment. The “RBD Glue Object” holds the pieces (the two boxes) together, but after collision with fluids the glue will not be break, even with glue strength “0”. It seems that the glue impulse, which is responsible for breaking the glue, is not calculated in interaction with a flip fluid. I added a passive ground and started a sim without the fluid and the behaviour of the glue DOP is like expected, the boxes are breaking and I get a value for the glue impulse.

Is there a limitation or do I have add data to the flip solver for calculating the glue impulse? Or is there another setup necessary? A played around with the “Glue Contraint Relationship” DOP as well, but with no success.

Sorry but I'm fairly new to Houdini