Import glb and gltf single meshes as root node

[elvisish]

Describe the project you are working on

Walking simulator.

Describe the problem or limitation you are having in your project

When importing a *.glb or *.gltf, even there is a single mesh node, the root is still a Node3D, it would be more convenient if it were auto-detected as a single mesh and imported as the root.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

It would make it easier to drag a glb or gltf directly into a MeshInstance3D mesharray without having to manually extract the node (either via copy/paste, new instance or extract during import).

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

An option to import a glb or gltf that has only a single mesh as the root imported node with a parent Node3D.

If this enhancement will not be used often, can it be worked around with a few lines of script?

It would be import code.

Is there a reason why this should be core and not an add-on in the asset library?

It would be import code.

[Calinou]

Unfortunately, doing so would also have a downside. If the structure of the glTF changes later on, the node structure has to be changed in a breaking way.

The current structure imposes some indirection, but it means the root node's type will never change unless you explicitly change it yourself in the Import dock.

[aaronfranke]

@elvisish I'm planning on working on similar functionality in the near future (next few months). I already opened a proposal here: #7494 and I opened this PR as a small prerequisite cleanup godotengine/godot#82988

My plan is to implement importing as a mesh resource instead of a mesh node, like you can already do with OBJ in Godot, but this is similar enough that I am closing this as a duplicate. If in the future after that proposal is implemented we decide importing as a scene with a single mesh node is useful functionality, we can do that.

[elvisish]

@elvisish I'm planning on working on similar functionality in the near future (next few months). I already opened a proposal here: #7494 and I opened this PR as a small prerequisite cleanup godotengine/godot#82988

My plan is to implement importing as a mesh resource instead of a mesh node, like you can already do with OBJ in Godot, but this is similar enough that I am closing this as a duplicate. If in the future after that proposal is implemented we decide importing as a scene with a single mesh node is useful functionality, we can do that.

Tbh, that sounds even better than what I proposed, a mesh resource to just drag into a meshinstance3d node. @Calinou sighested any changes to hierarchy (adding multiple meshes) would break if there was no root, could it work having Godot auto merge the meshes into a single mesh resource if more are added?