"Fix root motion initial rotation handling" commit breaks root motion completely


I cannot access UDN so no clue what the reason for this breaking change is, but it’s obvious by playing any animation (that doesn’t have initial rotation be zero) with root motion (my animations have +Y as forward, just like the sample ones do) that forward is now up, yaw is now pitch, etc. Can also see it with ‘log LogRootMotion log’ console command and looking at the message log to see that the axes it extracted are wrong.

engine 4.7.0 from commit a88ec9727f5a40044ceb533d7eadbc0b6ce3cbf3

Hi rajkosto,

In order to reproduce, please provide the detailed step by step process that led to this error as well as provide files where the initial rotation is not set to zero.


  1. Download mesh and anim sample
  2. Import PreviewMesh.fbx as skeletal mesh, creating new skeleton
  3. Import the other fbx files as animations using that skeleton
  4. For each imported animation:
    1. Open the animation asset in persona
    2. Notice the direction the animation is moving/rotating
    3. In the Anim Details panel, enable root motion
    4. The animation should be in-place now
    5. Under Show, check ‘Process Root Motion’
    6. Notice that the direction it’s applying Root Motion is completely wrong compared to step 2.

Reverting lines 783 and 784 in that commit to what they were originally, fixes the problem.

Hi rajkosto,

Thank you for your concise repro steps and sample animation (which I have removed from this post). I have entered the following bug report: [UE-6888] When this issue is addressed an update will be added to this thread.

Thanks again for your input towards getting this fixed!

This has been reported as Fixed in CL 2405814.

Hi. I am experiencing this in 4.7.3

Hi Crocopede,

I’ve tested this in 4.7.3 using rajkosto’s files and they are functioning as expected. Please recheck your set up and if you are still experiencing problems, post your assets in a zip file and include repro steps as rajkosto did previously.