Crash - Negative scale on child StaticMesh

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1

Hello,

editor crashes every time, in a special case where you :

  • set a negative scale on a child StaticMeshActor
  • change size of root component during game (the ‘Scene’ component in image)

It doesn’t seems to be a problem when values are changed directly in editor.

40717-ue4crashnegativescale.jpg
40717-ue4crashnegativescale.jpg1439×811 184 KB

I found a workaround by setting a invisible mesh already inversed (by rotations) and switching visibility between 2 meshs according if object is flipped or not. It’s not really a clean solution but result is here ^^

But still, it was a problem that took my afternoon to find so I hope this report could help someone that may have same problem than me.

Still a really nice engine, good luck !

2

Hi Begounet,

I wasn’t able to reproduce a crash by setting a mesh to a negative scale and/or setting root scene component scale during runtime. Does this happen in a new project, or only your current project? Which version of engine are you using?

Please find log after this crash occurs. You can find it in project folder under \Saved\Logs. Just latest log after crash and attach it here. If you can also copy text in Crash Reporter window after it crashes and post it here, that could be helpful. Thanks!

3

Hi ,

I tried method I described in a new project and indeed, it works now. I also imported new blueprint in my project and I didn’t get bug anymore.

That’s really weird that I crashed every time yesterday and no problem anymore today…

So, I tried to redo all this stuff for my project but problem still happens.
Here is graph :

40810-ue4crashnegativescale02.png
40810-ue4crashnegativescale02.png2137×581 167 KB

crash occurs when the “Set Relative Scale 3D” is used.
logs don’t help since crash is not “detected”. It’s like an infinite loop. I have to kill editor via Task Manager.

Edit : I don’t know how I can provide more information about this. Tell me if you have any idea.

Re-Edit : Forgot to answer to one of your question : I am using version 4.7.6

4

Okay, so it doesn’t occur in a new project, or if you import BP from new project to old project. But remaking BP in your current project causes same problem?

I believe this is related to a known issue that is being fixed currently (UE-13746), but I’d like to confirm by having devs look at it. Would it be possible for you to upload project somewhere and get me a download link? You can send it to me privately via PM on forums if you’d like:

Thanks!

5

Hi Begounet,

Thanks for project! I was able to reproduce what you’ve described, but I’m not sure what’s causing it. I think it may be entering an infinite loop as you suggested, but I wasn’t able to nail down exactly where or why. I’ve entered a bug report for it (UE-15206) and passed project on to our developers to see if they can find cause, and I’ll let you know as soon as I hear back.

6

Hey Begounet,

Just wanted to let you know that there were two bugs that were impacting your project, and both have been fixed internally. These fixes will be available in a future release of engine, likely 4.9. Thanks again!