Troubleshooting concrete‑like physics failures in Blender simulations

When a concrete‑like object behaves unexpectedly in a Blender simulation—such as passing through other geometry, collapsing instantly, or not reacting to forces—follow these steps to isolate the problem.

1. Verify the object's collision shape: select the object, open the Physics properties, and ensure the correct collision type (Mesh, Convex Hull, or Compound) is enabled.
2. Check the scene scale: concrete simulations rely on realistic units; if the model is too small or large, adjust the Scale in the Object properties or use the Scene Units settings.
3. Inspect the solver settings: increase the Substeps per frame in the Rigid Body World or Fluid Domain to improve stability, and raise the Solver Iterations if jitter appears.
4. Test with a simple proxy: replace the detailed mesh with a low‑poly cube of the same dimensions; if the proxy works, the original mesh may contain non‑manifold geometry or intersecting faces that need cleaning.
5. Rollback: duplicate the original object before making changes, and hide the duplicate; if a change worsens the behavior, delete the modified object and unhide the backup.
6. Verify the result: play the animation and look for expected interaction (e.g., the concrete slab rests on a support, cracks only under sufficient load).

If the issue persists, consider enabling the Debug option in the Physics tab to log collision events, which can help pinpoint whether the problem lies in the collision detection or the material properties.