[BUG?] Weird rotation issue with negative scale, possibly gimbal lock related

I’ve run into a weird rotation issue. Specifically i noticed it on the standard VRTemplate. Steps to reproduce:

  1. New VR Template project

  2. Add a CollisionBox or any Mesh and make a child under the MotionController Component

  3. Make the HandMesh child under the CollisionBox

  4. In the viewport, add a rotation to the HandMesh

You will see that for the Left hand it’s gonna do some snaps in rotations now and then at certain angles. So far i’ve tracked it down to only happen for the Left hand, which leads me to think that it’s to do with a negative scale of the HandMesh. See video of me reproducing it in a slightly different way, but it also shows the snap i talk about. Hope someone from dev will see this and can tell if this is an expected behavior or a bug?

Video of reproduction

Hello Jonas_Molgaard,

I was able to reproduce this issue on our end. I have written up a report and I have submitted to the developers for further consideration. I have provided a link to the public tracker. Please feel free to use the link provided for future updates. Thank you for your time and information.

Link: Unreal Engine Issues and Bug Tracker (UE-42619)

Make it a great day