Crash when unwelding a physics body

Development Asset Creation
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1

The ‘BaseObject’ blueprint spawns 10 ‘SubObject’ actors and welds them to itself. SubObject is just a cube.

After a three second delay it deletes one of these actors.

This makes it crash.

2

Steps to Reproduce
I am getting a consistent crash when unwelding actor bodies. This started happening after upgrading to 5.6.

It seems there is a mismatch between the number of shapes in the physics particle and the PushPhysicsState call.

I have attached a sample project that welds a bunch of actors together, then destroys one of them after 3 seconds. It will reliably crash when it unwelds the body.

Interestingly if I add a second cube to the ‘SubObject’ actor that is being welded, it does not crash. It seems to only happen if the actor being welded has only one shape.

3

Hello [mention removed]​

Thanks for reaching out and reporting this issue.

Thank you also for providing a repro project, I’ve run it and confirmed the crash.

I’ll investigate more, do a bug report, and reply once I have the tracking link.

All the best,

[mention removed]​

4

Hello [mention removed]​

I’ve made a JIRA report at: Unreal Engine Issues and Bug Tracker (UE\-308040)

Please note that it can take some time to be made publicly accessible.

We don’t provide updates on EPS, but if you would like to track the resolution, check the link for the status.

I believe we don’t have further actionable issues, so I’ll close the case.

Feel free to reply if you have anything else to add.

All the best,

[mention removed]​

5

Any updates on this? I’m running into the exact same issue after upgrading to 5.6.1