Create an armature with only empties

[fire]

Is your feature request related to a problem? Please describe.

We discovered one neat trick that can allow us to export gltf animations with only empties. This is a feature of the industry standard animation interchange format we would like.

Describe the solution you'd like

If we put all the nodes below the Armature node into a new skin, we can export animations from Blender with only empties and it'll import into Blender as a armature.

Describe alternatives you've considered

1. The industry standard animation interchange format
2. BVH
3. .blend
4. https://github.com/artellblender/empties_to_bones

Additional context

Reference implementation https://github.com/fire/avatar-wellness/blob/main/addons/bvh/import_bvh.gd#L54

[fire]

Here's the example glb produced.

AvatarSample_A.vrm_melt_anim_only-b1360511181690057d76f1d0ad9317cb.zip

References

• https://github.com/hurumeki/electron-pronama-chan/blob/master/assets/pronama/motion/melt.vmd
• https://github.com/madjin/vrm-samples/blob/master/vroid/AvatarSample_A.vrm

[julienduroure]

Hello,
Not sure to fully understand what you said, because you mix import / export considerations.

But, please test with https://builder.blender.org/download/experimental/gltf_vtree/

Select the armature, and export using "Include > Limit to Selected Object", it will export each bone as Empty, and export animations as well.
Seems this is your requirement?

[fire]

Let me check.

[fire]

While I wait for the 10 minute download..

1. Exporting empties from Blender exists.

Delete the meshes from scene and export. Leave the armature as is. Animations export.

2. This exported glb will probably fail to import into Blender as an armature and instead of skeletal animation it becomes an empties animation

[julienduroure]

Ok, seems I get it.
2 possibilities here:

• Force skin data to be created and exported, even if no meshes are exported. I first have to check if the glb is still a valid file regarding glTF 2.0 specification

• Force to import a glb file with only empties as an armature.

For import, I don't want to make it available by default, as this is a custom interpretation of content of the file. But it should be able to perform it on a user extension addon.

[fire]

Force skin data to be created and exported, even if no meshes are exported. I first have to check if the glb is still a valid file regarding glTF 2.0 specification

I believe our interpretation of putting armature joints into a global skin is valid. Can you check?

[julienduroure]

This is a duplicate of #822

[fire]

Can close or merge this report. I believe I have contributed an approach.