FBX Model with Animations working in 3.x, but not correctly in 4.x

[Whimfoome]

Godot version

3.4.stable and 4.x custom

System information

Arch Linux

Issue description

This model is extracted from unity package, to use in my game. When I was testing Godot 4, I noticed that the model is completely wrong, but in Godot 3.x, everything is working as expected.

Godot 3.4:

Godot 4 with no animation playing:

Godot 4 with animation playing:

I tried converting the format to gltf with Blender, but without success, Blender couldn't import it.
I found this FBX-glTF convertor, with which I converted the model to gltf, and could successfully import it to Blender and Godot, without any issues.

Steps to reproduce

1. Create new project
2. Import the Spider.fbx to the project files
3. Open in Godot 3 and Godot 4 to see the difference

Minimal reproduction project

Here are the model files instead:
Spider.zip

To convert the files manually with the tool on Linux, you can use wine

[fire]

The FBX importer needs to be updated for #53765.

I believe the changes are get_rest_pose * pose and rest_pose.affine_inverse() * pose() on setting.

[akien-mga]

This is probably fixed with the new FBX importer using FBX2glTF.
You can test it in Godot 4.0 alpha 6: https://godotengine.org/article/dev-snapshot-godot-4-0-alpha-6
This new importer might also be backported for the 3.x branch eventually.

If you still find issues with these models using the new importer, we suggest opening a new issue with details about the problems in Godot 4.0 alpha 6 or later.