Exported GLTF file is broken

[njourdane]

I try to export a simple gltf file of an assembly:

box = cq.Workplane().box(1, 2, 3)
asm = cq.Assembly().add(box)
cq.Assembly().add(box).save('box.gltf')

The script outputs:

RWGltf_CafWriter skipped node 'c44caed6-33fd-11ed-94b0-bf8faf8ebb27_part' without triangulation data

And the file seems broken. When I try to import it:

• in this gltf web viewer, it fails with the error i is undefined;
• in this other viewer, it fails with unknown error;
• in this other viewer, it fails with a json parsing error,
• with Blender, it doesn't fail but the model doesn't appear in the scene (only in the tree view).

Same errors if I set the output format explicitly with exportType='GLTF'.

[lorenzncode]

Duplicate of #993