[x3d-public] X3D minutes16 July 2020: Inline refresh, https, description; X3DUrlObject: glTF support

[Michalis Kamburelis]

niedz., 9 sie 2020 o 01:10 Michalis Kamburelis <michalis.kambi at gmail.com>
napisał(a):

> I looked at the new prose that requires support for glTF in Inline in X3D.
> Comments:
>
> 1. What is the goal of level 4 of the "Lighting" component,
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-WD2/Part01/components/lighting.html
> ? As far as I can see, level 3 of this component already includes
> everything -- all nodes (3 light nodes with all fields supported). I don't
> know what is different between level 3 and 4.
>
> 2. Level 4 of the "Networking" component (bottom of
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-WD2/Part01/components/networking.html
> ) now says this:
>
>     """
>     Support for .gltf (model/gltf+json) and .bin (application/octet-stream
> ).
>     Requires support for Shape component level 2 and Lighting component
> level 4.
>     """
>
>     My notes:
>
>     - The .bin extension (and MIME type) is not standardized, and it is
> also outside of scope for this X3D prose, IMHO. "Inline" node in X3D will
> *not* refer to .bin files. The glTF contents refer to .bin files. IOW, the
> support for external binary files (with whatever extension) is implicit in
> "supporting glTF".
>
>     - If you wanted to include the "packed" glTF files, then you probably
> wanted to instead mention .glb ("model/gltf-binary" MIME type). Possibly
> you mistakenly confused the .glb and .bin files.
>
>     - This clause is too imprecise, IMHO. What exactly glTF features do we
> require to be supported? As you saw in my document on
> https://github.com/michaliskambi/x3d-tests/wiki/Converting-glTF-to-X3D ,
> we have straightforward way to convert many things from glTF to X3D nodes,
> but not 100% of glTF. There are lots of details that still need to be
> filled to express 100% of glTF in X3D. Even some things I mention on my
> wiki are right now just extensions of CGE or X3DOM, which are not (yet?) in
> X3D spec. This is a work in progress, and I suppose it will happen across
> multiple implementations.
>
> My proposal:
>
> AD 1 - Remove level 4 of the "Lighting" component. It doesn't seem needed.
>
> AD 2 - Change the level 4 of the "Networking" component text, to require
> this:
>
>     """
>     Support for glTF models in Inline nodes, with .gltf (model/gltf+json)
> and .glb (model/gltf-binary) formats.
>     Minimum required glTF support:
>     - glTF transformation hierarchy (glTF "nodes", which correspond to X3D
> "Transform" nodes),
>     - glTF meshes,
>     - glTF standard physical materials (correspond to X3D PhysicalMaterial
> nodes, requires "Shape" component level 2 support)
>     - glTF unlit (KHR_materials_unlit) materials (correspond to X3D
> UnlitMaterial nodes)
>     - loading of external binary data referenced from .gltf files (e.g.
> for vertex coordinates)
>     """
>
> Regards,
> Michalis
>
>
>
> sob., 1 sie 2020 o 20:22 Don Brutzman <brutzman at nps.edu> napisał(a):
>
>> Discussed briefly with Dick and Michalis.  Also added requirement for
>> corresponding level 4 in Lighting component.
>>
>> On 8/1/2020 8:05 AM, Don Brutzman wrote:
>> > Important gap: we don't specifically call out glTF under Inline node in
>> Networking component.
>> >
>> > Existing prose:
>> > ===============
>> > 9.4.2 Inline
>> > [...]
>> > The run-time system can support any number of 3D model resource types
>> as long as those follow the abstract model definition (see 2.[RFC2077]),
>> provide a registered content type (e.g. model/x3d-xml, model/gltf-bin,
>> model/stl, etc.), and can be determined with some form of content
>> negotiation (see 2.[RFC2616]). The run-time system must support at least
>> one X3D type (e.g. model/x3d-xml) but can also support and negotiate any
>> number of X3D encodings and (optionally) non-X3D representation formats.
>> > ===============
>> >
>> > Recommended additions:
>> >
>> > "Support for loading glTF assets also requires support for Shape
>> component level 3."
>> >
>> > Support levels:
>> >
>> >      4
>> >      Model support
>> >      Support for .gltf (model/gltf+json) and .bin
>> (application/octet-stream)
>> >
>> > Normative references
>> >
>> > * GLTF
>> > * GL Transmission Format (glTF) Specification, The Khronos Group,
>> Version 2.0, 2017.
>> >    https://github.com/KhronosGroup/glTF/tree/master/specification/2.0
>> >
>> > Related reference section for glTF MIME information:
>> >
>> > [1] glTF File Extensions and MIME Types
>> >
>> https://github.com/KhronosGroup/glTF/tree/master/specification/2.0#file-extensions-and-mime-types
>> >
>> > All review and potential improvement of this important section is
>> welcome.
>> >
>> > all the best, Don
>>
>> 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
>>
>
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