Gltf doesn’t support skeletons without skinned meshes which is a part of the spec.
In my project we still need a way to export skinless skeletons with gltf. That’s why I added an extra step where I add bones info (skeleton name and the base matrix) to the nodes which I know are a part of the skeleton. This lets me to restore the skeletons on the client.
Here is a playground I created to demonstrate the issue I currently have with such manually created skeletons.
As animation is playing you clearly notice that the bones update the transforms with a delay.
To point out that it is actually an issue I added a commented-out line to switch to a completely similar animation but on a skeleton with an attached mesh.
[UPDATE] If you comment out the displayMode switch, the skeleton doesn’t move at all and stays in bind pose which seems just like a bug. Moving this to bugs.
I presume some update is not being done in time or it could be something with SkeletonViewer.
Would appreciate if someone could point me in the right direction.