Hi all, Im learning Houdini. Im doing a project which I created a simple wall and animated Cookie SOP to make some kind of crack on the wall. After that I imported it to RBD to break it. But there is weird problem that the wall's chunks appear to be missing during the animation of the crack. Im not sure it's a bug or something. I try to clean the wall geometry using Clean and try to tweak the RBD too but cant fix it. I have attached the scene file here. The scene is simple so it can be played fast. Please help :?

could be a bug.
However, I would not do the crack in SOPs though. Having “using Deforming Geometry” on in your RBD Glue object forces Houdini to calculate new collision volumes on every single frame, also it might be dangerous to deform the geometry that way, you're apt to get incorrect results.
Rather have a multisolver in your Dopnet and connect the RBD Solver to that as well as a SOP Solver, dive into the SOP Solver and do the cookie operation there, that way the animation is always based on the previous frame and your simulation might improve.
Why there are objects disappearing is another question though, check if your number / names of the groups are changing, if that's the case then that would explain it.

cheers,

Manu

Thanks for your suggestion, I will try this method