Why doesn't Child of work when exporting to Unity FBX?

Question

Blender

I export from Blender a character model with animation.
For some reason, the weapon in Unity, when playing the animation, just hangs in the bottom place, although it follows the hand in the blender.
Child of hangs on the weapon. Apparently, when exporting to FBX, there is some kind of garbage (
How to solve this problem?
Thanks in advance)

Answer 1

Because these are Constraints (limiters), they are not exported to FBX, only to blend.
But Unity itself does not import them from blend, and no one except Blender.
Child of - does not directly create a parent-child relationship as seen in the Outliner or Hierarchy(Unity) window.
So select the object that you want to make a child, then the future parent, and press
Ctrl-P, and choose the binding method you need.

Screenshot of the list of binding methods...

Official documentation!