Mirror on X FBX Animation

Development Character & Animation
1

Hello everyone,

I mirrored an animation using the following steps: select all keys → Mirror tools → planeX → export. The animation looks correct in Blender, but it breaks when imported into UE.

UnrealEditor_MILD5jnF64
UnrealEditor_MILD5jnF641298×926 74.7 KB

2

Hey @herve1234

I think it has to do with how blender handles negative scales or bone orientations when mirroring directly for animations which unreal can get a bit confused about when trying to export.

To help you figure some things out I would ask you to answer some things in return please.

  1. How did you apply the mirror transformation in Blender?
    Did you apply the scale (Ctrl + A → All Transforms/Scale) on the armature before exporting or did you use a specific add-on (like Dope Sheet mirror/Pose Library)?

  2. Which FBX export settings are you using in Blender?
    Specifically are you exporting with Only Deform Bones checked and what are your transform settings like Apply Transform or axis orientations?

  3. Did you mirror the actual rig/pose in Pose Mode or are you scaling the armature object negatively on X?

Once I have more context on your workflow I can walk you through the steps (or give a quick tip for baking the animation or using Unreal’s built-in Animation Data Mirror Table)

Looking forward to hearing back so that we can solve this!