[x3d-public] conversion of glTF metadata to X3D metadata

[Andreas Plesch]

Hi Holger,

Thank you for your feedback. I did not think too much about the name
for the Metadata node which holds the scene.extras json value.

To me "scene.extras" is more of a programming convention whereas the
value of a name string should be more abstract, or descriptive in a
linguistic sense. So a dot would mean a full stop which would not make
a lot of sense. But I can see that this is a rather aesthetic
consideration, and that a direct json path style name has its own
benefits by following very closely the glTF source..

Let us know what you think,

Cheers, Andreas

On Mon, Oct 9, 2023 at 7:25 AM Holger Seelig <holger.seelig at yahoo.de> wrote:
>
> In X_ITE I also create a WorldInfo, but parse only the toplevel metadata so far.
>
> I like the way you described it, but why do you translate 'scene.extras' to 'scene_extras'? I would leave it as it is.
>
> Holger
>
> --
> Holger Seelig
> Leipzig, Germany
>
> holger.seelig at yahoo.de
> https://create3000.github.io/x_ite/
>
> Am 09.10.2023 um 00:14 schrieb Andreas Plesch <andreasplesch at gmail.com>:
>
> glTF can contain rich metadata, on the toplevel and very targeted at
> any sublevel.
>
> At any level, there is an "extras" property which can contain any
> value including objects with arbitrary key:value pairs.
>
> At the toplevel, there is an asset object which has a set of defined
> keys such as "copyright" (as well as its own "extras" property).
>
> In addition to this unstructured metadata for core glTF, there is a
> metadata extension for more structured metadata, extensible through
> namespaces:
>
> https://github.com/KhronosGroup/glTF/blob/main/extensions/2.0/Khronos/KHR_xmp_json_ld/README.md
>
> There are many ways to map glTF metadata to X3D metadata. How should
> we manage this ? It may make sense to coordinate systematic behaviour.
>
> x3dom uses the WorldInfo node for toplevel metadata:
> - asset object properties go into the info field as key:value string pairs.
> - asset.extras go into a WorldInfo MetadataSet "asset_extras"
> - scene.extras  go into a WorldInfo MetadataSet "scene_extras"
>
> In addition, "extras" at lower levels go into MetadataSets of
> corresponding nodes, using the json value types for Metadata types.
>
> How do other browsers translate "extras" ?
>
> x3dom should also support the KHR_xmp_json_ld extension, by staying
> very close and literal to the glTF data.
>
> One feature of the extension is that sets (packets) of metadata are
> defined once at the toplevel, and then referenced (instantiated) from
> any other level. This seems to map well into DEF/USE. A large
> "KHR_XMP_GLTF" root MetadataSet would contain all metadata and just
> referenced by USE from Shapes/Material etc. I think this could work
> well. I think json property names can become Metadata name values, and
> json value types can be mapped into Metadata types.
>
> If there have been thoughts or attempts to implement the glTF metadata
> extension, any ideas or feedback would be great. Would it be useful to
> start to think about a xml Metadata schema which follows the glTF
> extension requirements and recommendations ? This may not be feasible
> due to the extensible nature of the extension..
>
> Cheers, Andreas
>
> --
> Andreas Plesch
> Waltham, MA 02453
>
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>


-- 
Andreas Plesch
Waltham, MA 02453