Allow renaming bones and blendshapes.

[lyuma]

The blend shape renaming feature will be used to implement custom glTF blend shape naming extensions. I have already developed an import helper using this feature in 3.2 based on the VRM glTF extension based on @fire 's code.

The bone renaming feature can enable scripts to provide rig normalization, among other things.

Due to the simplicity of implementation, I don't see a reason why further justification for the feature is needed, but I would be happy to discuss the use-cases in more detail if requested.

Attached I have a sample project which contains a tool script at Tools -> "Rename bone or blendshape" that replaces the first bone (if Skeleton3D selected) or the first blendshape (if MeshInstance3D selected) with the current datetime:

Sample project here: BlendshapeBoneRename.zip
Source code for GDScript tool available here: https://gist.github.com/lyuma/c707c74486a74112bc5a2791dda92154

((Notes about sample project:
Because importers in master branch haven't implemented blendshapes yet, this script does a hack to add a new blendshape if none exist, and it does display in the Console window.
Also, the tool script throws errors on the final print due to some GDScript glitches I keep running into, but the rename does work. I'll try and report those as separate bugs.))

Bugsquad edit:
Fixes: godotengine/godot-proposals#1672

[reduz]

I am not the code owner of this so I have no idea about it, I think @JFonS was going to work more on it also.
When we rename nodes, animation tracks are renamed automatically. Should it not happen also here too?

[fire]

It makes sense that animation tracks are also renamed.

[akien-mga]

I'll merge as it's been reviewed by @fire already, and is otherwise sitting in limbo. :)

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 3.4.

[GeorgeS2019]

@akien-mga I am using the latest Godot 4 master branch (Today), git cloned and compiled for mono and uploaded the VRM and it seems the blendshapes are still not correctly labeled as expected w.r.t. to Unity.

@fire timely feedback from him. I will check other models (non VRM) with blendshapes with the latest Godot 4 version.

[fire]

This is not a bug related to Godot Engine's gltf2 import.

VRM does not use the "defacto standard" blendshape naming.