Binding an event to onConstraintBroken crashes the editor on exit

Hi there,

Right now, no matter how I setup my project, if I bind an event to onConstraintBroken for a generated physics constraint, the editor crashes on exit. The project simulates and plays correctly, and the bound event fires correctly, but as soon as I hit escape, the editor crashes. I’ve uploaded all of the crashes I’ve hit today, but I figured I would spin up a thread here to try and cast a wide net. I can provide any additional materials or try out any more test cases if need be, but this is kind of blocking me from moving forward with my project at the moment.


Hi Brian,

Could you include the Epic ID or Machine ID from the Crash Report Callstack?

Also, please include a screenshot of your setup so I can make sure I’m testing this correctly.

Here is a quick screenshot of my blueprint setup. The ResetSetup macro flips a number of variables back to their initial default, plus breaks the generated constraint and destroys the constraint component.

Here is the callstack header:


I’m still having issues getting this to reproduce. Could you try reproducing this in a fresh project and if you can, post it here for me to test internally?

Thanks for getting back to me, I can even share the project where it’s repro’ing right now if you want? It’s just a small testbed for some features I’m working on.

Where can I put them to get these projects to you easily?

If they are smaller than 5 MB (probably not) you could upload them here. Or upload them to a site like Googledrive or Dropbox and then post the link here.

If you don’t want to post it here, feel free to private message me the link over the Forums.

Hi Brian,

I haven’t found the ‘exact’ cause, but I think you can fix it by removing the Break Constraint node from the Macro. It looks like this is a second break constraint because the blueprint still works correctly with it disconnected.

I’m still investigating to try to find out exactly why the editor is crashing. I’ll post back when I have more news.

Let me know if the above alteration works for you.

Thanks for looking into this, I can confirm that not breaking the constraint twice is able to get around the issue. Super weird that it’s crashing on exit though. Thanks TJ!

I attempted to reproduce the crash in a more simplistic way while still breaking the constraint twice, however I can’t get the crash to occur. It must be some combination of what you are doing.

The main thing is that it’s now working properly for you. If you start experiencing the crash with the exact same callstack again, please post back here to let us know.