[x3d-public] X3D meeting minutes 15 FEB 2019: glTF and X3Dv4 progress

Fri Feb 15 09:44:11 PST 2019

0. *Attendance*  Anita Havele, Vince Marchetti, Michalis Kamburelis, Nicholas Polys, Dick Puk, Don Brutzman

Members and invited experts are welcome.  We are an open organization.

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	http://www.web3d.org/working-groups/x3d

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1. *Last week's minutes included this week's agenda*

X3D meeting minutes 3 (actually 8) FEB 2019: X3Dv4 mantis github specification changes, glTF plans, MetadataSet
http://web3d.org/pipermail/x3d-public_web3d.org/2019-February/010048.html

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2. *Upcoming events*

a. Web3D 2019 Conference: Call for Papers

	http://www.web3d.org/news-story/web3d-2019-call-papers

	http://www.web3d.org/event/web3d-conference-2019

	18 March 2019 Paper submission deadline

b. Semantic 3D Workshop accepted at EuroGraphics 2019

	http://semantic3d.org/workshop
	6 May 2019, Genova Italy
	Organizers Jakub Flotyński,Patrick Bourdot, Marc Erich Latoschik, Krzysztof Walczak
	3 March 2019 submission deadline

c. AMIA 2019 Informatics Summit Workshop: Web3D Quickstart, Standards-based 3D in Health and Medicine

	March 25, San Francisco.
	Organizers Nicholas Polys and Peter Sforza Virginia Tech, Michael Aratow and Anita Havele Web3D Consortium"
	Announcement, details and tweet:
http://www.web3d.org/event/amia-2019-informatics-summit-workshop-web3d-quickstart-standards-based-3d-health-and-medicine
https://informaticssummit2019.zerista.com/event/member/543088
https://twitter.com/Web3DConsortium/status/1095736483317657601

"Programmatic Theme: Data Science.
Patient outcomes and enterprise efficiencies depend on the quality and timely delivery of information. Increasingly, 3D information are being generated and used in healthcare; this workshop will explore and demonstrate the value of interoperability and the opportunities of open, International Standards technologies. From imaging and scanning to 3D printing and Virtual Reality, Extensible 3D (X3D) provides for durable data interchange and portable presentation natively over the WWW. This workshop will cover the wide range of methods and patterns used to develop interactive 3D applications based on royalty-free and open ISO-IEC standards. As a high-level scene graph language and API above the graphics library, Extensible 3D (X3D) provides a suite of standards including multiple data encodings and language bindings. We will explore the myriad of approaches, tool chains, and applications for building X3D objects and scenes, especially concerning medical and health informatics.

Learning Objective: This workshop serves as a broad introduction to the technologies and capabilities of the ISO-IEC Web3D standard Extensible 3D (X3D) and Humanoid Animation (H-ANIM). Attendees will gain a comprehensive understanding of the standard specifications, tool chains, and publishing platforms for 3D health informatics information. The materials, including the presentation and links will be available for attendees to follow-up for more in-depth and technical resources."

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3. *Review of last week's minutes*

Steady progress with Mantis and Github

Dick and I plan to keep track of Mantis decisions and update Github specifications.

Design Printing and Scanning group is about to take next pass on PointProperties.

HAnim specification resolution: two points remain regarding HTML publication.  We've asked SC4 TC184 about AP242 spec and other exemplars.  Next Tuesday Dick and Don plan to either (a) finish HAnim FDIS, or (b) write letter to ISO and Web3D Board of Directors on remaining blockers.

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4. *glTF progress: X3Dv4 specification outline is getting clearer*

We were happy to have Michalis with us. His efforts are really important as basis for our path forward, and he reports working closely with Andreas.  He will be posting again soon regarding further progress regarding Physically Based materials, suggesting example X3Dv4 specification prose.

We discussed this paragraph from last week's minutes.  It still makes sense.
"The issue of inconsistent lighting among glTF implementations appears to be a side effect of their not yet formally specifying lights.  Nevertheless the PBR lighting equations are well defined.  Therefore we expect to be able to upgrade the X3Dv4 lighting model, lights, materials and rendering to support Physically Based Rendering PBR materials consistently and unambiguously."

Michalis described nearly identical conclusions from his work.  We indeed seem to have a good basis for upgrading X3Dv4.

Vince brought up important points.  Presumably we will list glTF 2.0 as normative reference for X3Dv4.0, while fully expressing the lighting equations in our specification.  Thus we will not be in any kind of future-dependency tail-chase situation with future glTF possibilities.

Dick pointed out that the specification will also need to get specific when describing what happens when loading glTF models.

"Normative reference" means that a citation is authoritative, and necessary if someone wants to understand the X3D specification fully.

Another key question: are X3Dv4 implementations likely to include both lighting models, the old and the new?  Answer yes: both are needed.  It is further technically possible to use each within a given scene (i.e. different shaders get applied in tandem).
- Phong lighting model, and
- Physical lighting model.

If a graphics artist (i.e. scene author) doesn't like how his scene "looks' with lighting effects of both Phong and Physical rendering of objects, then they can upgrade their models.

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5. *Projective Texture Mapping PTM and shadows*

Last week we wondered if these topics are closely related to PBR since they are both highly dependent on rendering.

There is a connection regarding how objects will appear with respect to Phong and Physical rendering, but the algorithms for PTM and shadows are relatively independent.  So each set of work has influence on the other, but implementers can add each incrementally.

Interesting point when we get to consider shadows more deeply: are they associated with light sources?  That is one way to do it...

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6. *X3Dv4 Progress*

a. X3Dv4 pages review: comments or additions welcome.

	http://www.web3d.org/X3D4

Suggest swapping url with the cross-link

	http://www.web3d.org/X3Dv4

Long-running and consensus based:

	http://www.web3d.org/wiki/index.php/X3D_version_4.0_Development

Hoping to keep evolving this page, and better note progress.

We will add sections, and begin moving Candidate Capabilities topics around, by consensus:

- Accepted Capabilities (well defined in Mantis, ready for github draft specification)
- Candidate Capabilities
- Deferred Capabilities
- Excluded Capabilities

Weekly progress updates welcome!  We will begin sorting next week week.

Anita is correct: our focus needs to be really tight on achieving Accepted Capabilities.  This is our dedicated focus.

b. X3Dv4 design review: Web3D 2017/2018 session notes.  Please review as preparations for upcoming email and meeting discussions.

	"Future of X3D" presentation and detailed notes from Web3D 2017 Conference, Brisbane Australia, 7 June 2017.
	http://www.web3d.org/sites/default/files/page/X3D%20Version%204/FutureOfX3D.pdf
	http://www.web3d.org/sites/default/files/page/X3D%20Version%204/FutureOfX3dWeb3d2017June7.pdf
	http://www.web3d.org/sites/default/files/image/wg/X3D%20Version%204/PresentationPanoramaFutureOfX3dPaulGrimm20170607_135611.1600x492.jpg

Based on discussions in Korea, Don has written a further-distilled diagram for HTML5/X3D event models.  Essentially each (HTML5 and X3D) have internal event loops, and natural times to exchange events is at the each loop. This will get pushed to group in near future.

Expected review:
- how to we revise the architecture planning documents?
- how have X3DOM and X_ITE each implemented events?
- what sections in existing X3D specification need to be modified?
- does HTML5-X3D prose go into X3D Architecture 19775-1 or elsewhere, perhaps 19775-3?

Great question for next 1-2 months: what will our X3Dv4 announcement say at Web3D 2019 conference?

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7.  *Topics for next week*

a. Accepted/Deferred/Excluded Capabilities
b. X3Dv4 event-passing diagrams
c. PTM cued up for review.

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Another stellar meeting - thanks for everyone's important contributions today, what a great team effort.

Having fun marching towards X3Dv4!   8)

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