Absolute / relative / internal assets in glTF

[bdoubrov]

glTF is based on JSON which then references multiple binary data (=assets) that contain model data, material info, textures, etc. This binary data may be placed into JSON file using base64 encoding or they may reference external files using a URI. In the examples this URI is typically given relative to the location of the jlTF document.

Questions:

• are absolute URI allowed? Do we allow them in the glTF embedded into PDF?
• how do we pack the assets (referenced via absolute or relative URIs) into PDF? Do we have the exact match with PDF 2.0, 13.7.2.3.2 The assets name tree?

[bdoubrov]

According to glTF URIs documentation, the only URIs permitted by glTF are:

• data URIs, which actually embed the data directly into the glTF JSON
• relative URLs without scheme, authority, or parameters

An additional implementation note says that:

Clients can optionally support additional URI components. For example http:// or file:// schemes, authorities/hostnames, absolute paths, and query or fragment parameters. Assets containing these additional URI components may be less portable.

I would suggest to forbit these additional URI components when embedding glTF JSON into PDF

[philspreier]

Discussed in meeting today. Agreed to Boris proposal that we allow data and relative URI's, but not additional URI components.

Relative URI would be added as assets in the RIchMedia annotation.