Scale and GLTF metadata

Continuing the discussion from Download API and metadata:

We are considering adding a GLTF extension to mark models that have “true scale”, i.e models that have correct real world dimensions. As you have probably discussed this topic extensively I would value your opinion.

This would be an extension at the top level node without parameters that would indicate the model had been scaled ready for use in a real-world-sized environment.

I can’t see any reason to have parameters, but we might also want to include another extension that gives a hint about placement: elephants on the ground, birds in the air, that kind of thing, but it’s a secondary consideration.

I appreciate that this isn’t going to find it’s way to your GLTF export any time soon, but your opinion and experience would be very welcome.