Isaac Sim crash on simulation start

Hi, I am trying to do a simple simulation with a pair of rails (fixed) and two cylinders (rigid body) with colliders. On simulation start, I get a lot of error messages and the simulation stops. After that, Isaac Sim will not work properly and crash eventually. I am attaching the scene and the logfile.

Any help appreciated.

bogie_crash_220714.usd (712.0 KB)
kit_20220714_162050.log (1.1 MB)

1 Like

I did another test with only one cylinder elevated a bit. Running the simulation, it does not crash, but when it lands on the rail, it wiggles strangely. When I move the cylinder during simulation (Shift-Mouse drag), the simulation crashes sometimes. This means, I get errors in the log and the simulation is interrupted.
bogie_crash_220714_one_cylinder_.usd (712.0 KB)

Another weird example.

bogie_crash_220714_two_cylinders_falling.usd (712.1 KB)

When I set the collider approximation from triangle mesh to mesh simplification, the simulation runs much smoother.

By the way, the rails are exported meshes from Maya.

It seems the problem has to do with the implementation of the custom geometry collider of cylinders. When I use a cylinder mesh with convex hull, the problem is at least less pronounced, if not gone. Unfortunately the convex hull approximation is too rough for a cylinder to smoothly roll on a surface.

Is this perhaps related to Physics on simple objects inconsistent

That issue is open since Feburary and there is an internal ticket OM-43454.

If there is a relation, what’s the status of OM-43454?

Bruno, thank you for the internal ticket reference. it seems the issue is still backlogged, but there’s a workaround for the issue for now:

Try to increase [Contact Offset] and [Rest Offset], so that

0 < RestOffset < ContactOffset


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