Good point. JOINTS_0 and WEIGHTS_0 are part of the standard, each holding 4 values. We could use non-standard JOINTS_1 and WEIGHTS_1 to add four more. This should let us work up to Unreal Engine’s limits.
I’ll look at that soon & make sure re-import works.
@ when do think skeletal mesh import will be supported by unreal? - This would solve so many problems for me as a blender user. I just want to be able to simply skeletal retarget my characters to the mannequin 
I just released a preview version of glTF for UE4.
It supports to import the skeletal mesh and the animation sequence. You can download it from glTF for UE4 & 5 by Code 4 Game. And it is free and an open-source project in GitHub - code4game/glTFForUE4: Import glTF 2.0 in Unreal Engine 4 & 5.
By chance, have you tested it with GitHub - KhronosGroup/glTF-Blender-Exporter: Moved to https://github.com/KhronosGroup/glTF-Blender-IO. exporter ?
Sorry, I have not tested the glTF-Blender-Exporter.
Hmm… But how do you export glTF from Blender in order to test your UE4 import plugin ?
@ Given that it looks like glTF will become Unreal’s preferred option to FBX, will there also be an export scene to glTF function?
ditto–are you supposed to use [GitHub - KhronosGroup/glTF-Blender-Exporter: Moved to https://github.com/KhronosGroup/glTF-Blender-IO. , to export and test plugin,I presume so, clarification ?
That’s what I figured, since it’s “official” glTF exporter for Blender.
Does this importer support runtime loading of assets? I believe that’s part of the design goal of the spec, runtime asset delivery. Runtime asset delivery of glTF would certainly make my life easier.
I created a 3d model using Lego (for a construction project POC) trying to export it in glTF from Sketchfab create some odd result in UE4
Sketchfab result
glTF exported from Sketchfab and imported in UE4.19
Not sure if this is only my fault, can anyone try it
Tested with GitHub - KhronosGroup/glTF-Blender-Exporter: Moved to https://github.com/KhronosGroup/glTF-Blender, works fine, it only needs to manually apply scale (apply modifiers on export doesn’t work)
What about exporting multiple anims (anims being separate Actions) ?
You’re importing a SCENE. I think it was mentioned by plugin’s developer, that scene import is not yet implemented, and plugin will import separate meshes instead.
I’m not , but comparing CURRENT (post-4.20) and 4.19 plugin’s code - there’s no differences, except changing a few lines possibly to maintain changes in engine’s API. I.e. 4.20 version of plugin is exactly the same as 4.19.
That doesn’t sound too exciting 
Sadly yes, the feature set is identical between 4.19 & 4.20. I planned to spend more time on this, but got pulled onto another project leading up to the 4.20 release. There’s some changes under the hood to support SkeletalMesh but not enough to expose as a new feature.
Spent last week at SIGGRAPH talking to other people / companies in the glTF ecosystem – it’s really catching on! I’ll do my best to get things moving faster on our end.
It sounds like you’re spending your free time for that, or like you have some degree of freedom choosing what you’re doing next (but were forced to work on something else). Was that work an Epic’s initiative, or your personal one?
My company also was and SIGGRAPH and they’re talking about major interest to glTF over different companies.