[x3d-public] glTF Interactivity Extensions Approach Finalization: Your Feedback Needed!

John Carlson yottzumm at gmail.com
Fri Jun 6 10:46:51 PDT 2025


I think it’s best to work with vendors to make sure that support for X3D
“interactivity” is translated to and from their internal data structures,
rather than direct glTF-X3D conversions.

That is, I we could use more examples of Blender interactivity to translate
to X3D.  People should also try to load animations (interactivity) into
Blender as well.

John

On Fri, Jun 6, 2025 at 12:35 PM Brutzman, Donald (Don) (CIV) via x3d-public
<x3d-public at web3d.org> wrote:

> [added cc: x3d-public since all referenced information is public]
>
> Thank you Nicholas for flagging this important activity.
>
> Dick and I reviewed this interesting draft extension for glTF this morning
> as part of our regular specification editors' teleconference.
>
>    - X3D Standards Working Group
>    - https://www.web3d.org/working-groups/x3d-standards
>
>
> Helpful summaries and draft specification of proposed glTF capabilities:
>
>    -
>    - glTF Interactivity Extensions Approach Finalization: Your Feedback
>    Needed!
>    -
>    https://www.khronos.org/blog/gltf-interactivity-extensions-approach-finalization-your-feedback-needed
>
>    - glTF™ 2.0 Interactivity Extension Specification (draft)
>    -
>    https://github.com/KhronosGroup/glTF/blob/interactivity/extensions/2.0/Khronos/KHR_interactivity/Specification.adoc
>
>    - YouTube: Peter Martin (Adobe), Khronos session at SIGGRAPH 2024,
>    Interactivity Extension in glTF
>    - https://www.youtube.com/watch?v=2HwMZ7bj4ew
>
>
> Strategic Review
>
>
>    - The X3D community and Web3D Consortium needs someone interested in
>    observing and (possibly) participating in key efforts such as this.
>    - The work looks thorough and consistently high quality, matching
>    other Khronos specifications.
>    - The Khronos license terms appear to be unchanged since our prior
>    review.
>    - Use of the extension requires either membership as an Adopter of
>       Khronos IPR policy, or else " express prior written permission of Khronos."
>       - Patented materials are included in the specification (though not
>       specifically identified).
>       -
>       https://github.com/KhronosGroup/glTF/blob/interactivity/extensions/2.0/Khronos/KHR_interactivity/Specification.adoc#foreword
>       - No plans are evident at this time for standardization with ISO
>    under royalty-free terms.
>    - X3D Architecture cannot require adoption of closed (i.e. Khronos
>    adopter-only) technology, but Web3D Consortium members and X3D community
>    participants can find patterns for mapping correspondences between X3D and *KHR_interactivity
>    *extension, just as has occurred previously with glTF 2.0 standard.
>    - X3D Architecture can align with and suggest optional support for
>    external specifications that are not fully open.  Prerequisites for such
>    support are familiar: member interest, multiple independent implementations
>    (with at least one in open source), examples that demonstrate capabilities
>    and can test conformance.
>
>
> Technical Review
>
>    - This extension is for JavaScript programmers who want to animate
>    glTF models.
>    - We saw a great number of similarities to the X3D event model:
>    directed acyclic graph, strong typing, etc. etc.
>    - KHR_interactivity inclusion of types and nodes and parameter/fields
>    looks to have complete expressive power regarding glTF model.  This is
>    similar to the complete expressive power that X3D animation has long
>    provided.
>    - We saw no blockers preventing the construction of X3D event chains
>    with identical functionality.
>    - From our X3D-informed point of view, mapping the ECMAScript/JSON
>    structures in *KHR_interactivity *appears to be a good candidate for
>    people to write converters and importers to/from X3D.
>    - At first we did not see similar capability for X3D accessType
>    (eventIn eventOut initializeOnly inputOutput) but the following paragraph
>    seems to have similar (functionally compatible) expressiveness.
>    - 3.2.4. Unsupported Operations
>       -
>       https://github.com/KhronosGroup/glTF/blob/interactivity/extensions/2.0/Khronos/KHR_interactivity/Specification.adoc#nodes-noop
>       - The terminology used for "flows" and "sockets" do not refer to
>    any networking concepts or streaming protocols.  Rather they
>    descripe pointers to ECMAScript functions.
>    - The extensive math library defined in the specification provides
>    some additions to the stock JavaScript math library.
>    - All of the programmatic math-library constructs described appear to
>    be implementable in X3D Script node using ECMAScript, already.
>
>
> Recommendations
>
>
>    - Further expert assessments and collaboration betweed Web3D and
>    Khronos are always welcome.
>    - Model conversion and Inline examples, back and forth between X3D and
>    glTF *KHR_interactivity *extension, are always welcome.
>    - No formal action by Web3D is needed until some future day when
>    various sensible glTF extensions might get advanced by Khronos to ISO.
>    - Potential additions to future X3D standard are maintained at
>    - X3D Architecture version 4.1 (draft)
>       -
>       https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/Architecture.html
>
>
> Further discussion and improvements to this assessment are also always
> welcome.
>
> Have fun with X3D!  🙂
>
> Sincerely, Don Brutzman and Dick Puk
>
>
> 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
> https://faculty.nps.edu/brutzman
>
>
> ------------------------------
> *From:* Polys, Nicholas <npolys at vt.edu>
> *Sent:* Thursday, May 22, 2025 11:18:17 AM
> *To:* x3d at web3d.org <x3d at web3d.org>; Web3D Communications Team <
> communications at web3d.org>
> *Subject:* glTF Interactivity Extensions Approach Finalization: Your
> Feedback Needed!
>
>
> https://www.khronos.org/blog/gltf-interactivity-extensions-approach-finalization-your-feedback-needed
>
> In June 2024, the Khronos 3D Formats Working Group released the glTF 2.0
> Interactivity draft extension (KHR_interactivity) for public review and
> comment. Now, thanks to valuable community feedback and almost a year of
> continued development, we are nearing the finish line on releasing
> KHR_interactivity together with a set of companion extensions. These
> extensions provide a straightforward, standardized method for embedding
> interactive behaviors directly within glTF 3D assets, enabling developers
> to create engaging 3D experiences with consistent interactive functionality
> across different platforms and applications.
>
> As we prepare to submit the glTF interactivity extensions to the Khronos
> Board for ratification, we are seeking final input from early adopters. We
> invite content creators, artists, implementers, and engine developers to
> explore and experiment with the openly available tools and sample assets to
> integrate interactive glTF content into their projects.
>
> Learn more: https://lnkd.in/gkSqR_HF
>
> --
> Nicholas F. Polys, Ph.D.
>
> Director of Visual Computing
> Virginia Tech Research Computing
>
> Department Editor: @theSource
> IEEE Computer Graphics & Applications
>
> Affiliate Professor
> Virginia Tech Department of Computer Science
> https://people.cs.vt.edu/~npolys/  <https://people.cs.vt.edu/~npolys/>
> _______________________________________________
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>
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