[x3d-public] glTF asset metadata support

[Don Brutzman]

Cool.  An interesting X3Dv4 variation (design pattern actually) is to embed MetadataSet (for all structured metadata information) in WorldInfo.

Dick Puk notes that WorldInfo is also a legal top-level root node, so it is a good way to include structured metadata for the scene graph of an X3D model.

On 1/3/2020 7:42 AM, Andreas Plesch wrote:
> Thanks. Boiling down to two take aways, ignoring for now the proposed
> glTF XMP extension:
> 
> 1) When I looked at the gltf asset property, I found that the X3D
> WorldInfo node seemed to be a better match than Meta statements
> because gltf asset can have an extras property which is best mapped to
> a X3D Metadata node which in turn WorldInfo also has. In addition,
> WorldInfo makes a distinction between Metadata and its info field,
> which is similar to how gltf asset makes a distinction between
> "copyright", "generator", "version", "minversion" properties and
> extras. A related question is if there is an informal, but established
> X3D convention for the strings in the MFString info field of
> WorldInfo. x3dom maps asset properties as  key:value, for example
> "copyright:(2020)J.Smith".
> 
> 2) The gltf extras property can be used for any gltf node such as
> meshes or textures. It is best preserved as a X3D Metadata node of an
> equivalent X3D node.
> 
> 
> 
> On Fri, Jan 3, 2020 at 3:46 AM Don Brutzman <brutzman at nps.edu> wrote:
>>
>> Thanks for these great contributions Andreas.  I've added this note to the Mantis issue.  When the time comes will be keen to work with you to get X3Dv4 specification and various implementations all aligned correctly.
>>
>> On 1/2/2020 7:15 PM, Andreas Plesch wrote:
>>> There is currently an industry effort to define better structured metadata discussed here:
>>>
>>> https://github.com/KhronosGroup/glTF/pull/1553
>>>
>>> This effort follows the XMP standard used for some media.
>>>
>>> I believe for x3dom we made an attempt to preserve metadata when inlining gltf. Yes, here is the relevant translation in code:
>>>
>>> https://github.com/x3dom/x3dom/blob/16cdee773c81f388c4b46b8aae76384a59dd1ecd/src/util/glTF/glTF2Loader.js#L55-L157
>>>
>>> The asset info goes into a worldinfo, and extras for other items go into metadata.
>>>
>>>
>>>
>>>
>>>      Date: Thu, 2 Jan 2020 09:08:13 -0800
>>>      From: Don Brutzman <brutzman at nps.edu <mailto:brutzman at nps.edu>>
>>>
>>>
>>>      Great metadata discussion on the weekly Design Printing Scanning teleconference.
>>>
>>>      We decided to specifically call out that any metadata in a glTF asset (model) needs to get loaded as X3D metadata.
>>>
>>>      Feedback and improvements welcome.
>>>
>>>      ================================================
>>>
>>>      Mantis issue 1272: glTF import needs to include metadata import
>>>      https://www.web3d.org/member-only/mantis/view.php?id=1272
>>>
>>>      When loading a glTF model, whatever metadata might be embedded needs to appropriately converted into X3D head/meta elements or Metadata* nodes as well.
>>>
>>>      Reference:
>>>      - - - - - - - - - - - - - - - - - - - - - - - - -
>>>      glTF asset: Metadata about the glTF asset.
>>>      https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#asset-1
>>>      Properties Type Description Required
>>>
>>>      * copyright string A copyright message suitable for display to credit the content creator. No
>>>
>>>      * generator string Tool that generated this glTF model. Useful for debugging. No
>>>
>>>      * version string The glTF version that this asset targets. ? Yes
>>>
>>>      * minVersion string The minimum glTF version that this asset targets. No
>>>
>>>      * extensions object Dictionary object with extension-specific objects. No
>>>
>>>      * extras any Application-specific data. No
>>>
>>>      Additional properties are allowed.
>>>      - - - - - - - - - - - - - - - - - - - - - - - - -
>>>
>>>      all the best, Don
>>>      --
>>>      Don Brutzman  Naval Postgraduate School, Code USW/Br brutzman at nps.edu <mailto:brutzman at nps.edu>
>>>      Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
>>>      X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman
>>>
>>>
>>>
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>>
>>
>> all the best, Don
>> --
>> Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
>> Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
>> X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman
> 
> 
> 
> --
> Andreas Plesch
> Waltham, MA 02453
> 


all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br       brutzman at nps.edu
Watkins 270,  MOVES Institute, Monterey CA 93943-5000 USA   +1.831.656.2149
X3D graphics, virtual worlds, navy robotics http://faculty.nps.edu/brutzman