Simplified from #11697 since I’ve figured out the issue.
Here is a simple animation i created in 3ds max:
You can see the pivot point of the red bar has been moved to one end, and it is animated to swing around the pivot.
Loading this in Clara.io:
The animation plays correctly, and the pivot point is displayed in the correct place.
Loading in Paint3D in windows – animations are not played, but the bar is in the correct place:
Finally, loading in three.js and I get this:
The loader has assumed that the pivot point is at the centre of the bar and moved it accordingly – the animation plays around this new pivot.
Here’s the FBX file: