Fbx export: random, weird bones rotation artefact
Open, Needs TriagePublic

Description

System Information
Win10

Blender Version
2.79

Short description of error
First, sorry if this report is a duplicate, i've found some similar report but could not make sure they're the same.
A few bones orientation are wrong when exported to Fbx then imported in Unity or Unreal Engine. Importing back the Fbx in Blender is ok, but not in these game engines.

Exact steps for others to reproduce the error
-Import the attached fbx file in Blender, then check it's ok.
-Export it to fbx using the default options
-Import in Unity or Unreal Engine. The lips, cheeks and chin bones are distorted. After investigation, moving of +/-0.01 the bones transforms in Blender before exporting can fix it. So it seems to be an imprecision error at some point...

Details

Type
Bug

Dont have access to Unity/Unreal atm.
@lucas veber (lucky3) : could you upload a screenshot of both Unity and Unreal as a reference?

Sure thing. Actually it's the same issue in Maya in case you're able to test it. Haven't tested with 3dsmax but i'd assume it may be the same.
Here is attached a screenshot.