Quick answer: Unreal physics asset bones rotated 180 degrees after re-importing FBX? Coordinate system mismatch between DCC and UE - set Import Axis Conversion in FBX import.
Re-imported character mesh from Maya. Physics asset bodies now upside-down.
Set Import Axis Conversion
FBX import > Axis Conversion = Maya YUp. Or whichever your DCC uses. Defaults don't always match.
Or use a Linker
Import via a custom asset linker that swaps axes consistently. Removes user-side guesswork.
Verify with a test mesh
Import a known-orientation test cube. If the cube faces wrong, the entire import config is wrong; fix once for everything.
“Axis conventions are silently incompatible between DCCs. Import settings bridge.”
Establish 'one DCC, one axis convention' for your project. Cross-DCC pipelines multiply the bug surface.