Scene Graph resolves incorrectly with a project upgrade from 4.11 to 4.12

Hi there,

We have a simple project example (see attached) where we have a 4.11 project and two static meshes. One is a child of the other. They both have various changes to their scales and rotations. Now open this project in 4.12 preview 5 and you will find that the child mesh is rotated in a different way.


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Hi DecoDigital,

I can reproduce this in the project that you attached, but to get a better understanding of what is going on, I tried reproducing it in a new blank project. However, I couldn’t get the same results.

What are the exact steps that you followed to add the StartMap actor to the level, then add another and attach it?

This is what I did:

  • Created a new blank project

  • Imported a static mesh

  • Dragged StaticMesh1 from the Content Browser to the viewport

  • Changed it’s Transform, Rotation, and Scale

  • Dragged another static mesh into the viewport (StaticMesh2)

  • In the World Outliner, dragged StaticMesh2 onto StaticMesh1

  • Changed StaticMesh2’s Transform, Rotation, and Scale

  • Saved all & closed the editor

  • Converted the project to 4.12 P5 (and 4.12 official release)

Also, how did you make the StartMap asset? 3DsMax, Maya, Blender, etc?

Hi there, I was able to reproduce again from scratch on a different PC, this time with 4.12 release.

The following were my steps:

  • open 4.11
  • select blank project with no starter content
  • create a folder called ‘Maps’ and save the map as ‘StartMap’
  • import the static mesh
  • drag an instance of the mesh into the map
  • set its scale to 1.0, -1.0, 1.0 <---- note the Y field is minus one
  • drag in another instance of the mesh and make it a child of the first one
  • set its scale to -1.0, 1.0, 1.0 <---- note the X field is minus one
  • set its rotation to 0, 0, 130
  • save all
  • open with 4.12 and observe rotation change

Let me know if you need any more info!


Thank you for the additional info. I was also able to reproduce this in a new 4.12 project. I’ve created JIRA UE-31521 for the issue and our developers will be investigating further. We will post here with updates as we have them.

It’s directly caused by setting the parents scale to a negative value. So not using a negative value here would be the obvious workaround. Let me know if that will work for now or if using a negative value here is integral to your game.



Hi TJ, glad to hear that you were able to reproduce the problem. Sadly this is integral to our (fairly large) console title. We’ve used it everywhere. For various reasons we had to upgrade to 4.12 and with certification for the various platforms soon, we could really use some attention on this, as either a hotfix or even better, as a patch for the engine source code.

Thanks again!

The devs suspect that this is due to some changes that was made to negative scaling in 4.12. If a fix can be determined in time, we are hoping to get this resolved asap. I can’t make any version promises right now but we will update this thread as soon as we know more.