[x3d-public] X3D Working Group meeting minutes, 17 August 2018: ISO specifications planning, Khronos glTF, SIGGRAPH, Web3D Conferences, regexes, proto expander
Don Brutzman
brutzman at nps.edu
Fri Aug 17 10:22:39 PDT 2018
Minutes for X3D Working Group weekly teleconferences, Friday 17 August 2018, 0800-0930 pacific time. Members and invited guests welcome.
Web3D Teleconference Information
http://www.web3d.org/member/teleconference-information
Attendees: Vince Marchetti, Dick Puk, Don Brutzman. Regrets: Anita Havele and Nicholas Polys.
We reviewed recent progress and events. A lot is happening!
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1. We've had a productive series of weeks with ISO SC24 meetings in France and SIGGRAPH in Vancouver.
Vince and Dick reported on the ISO joint working group meetings in Toulouse France, 6-10 August 2018. These discussions were very successful and there is excellent collaoration underway.
- Charles Whitlock ISO SC24 convener will be putting resolutions online in ISO area
- Jean Brange is expected to put slidesets from ISO/TC184/SC4/Joint Working Group 16 (JWG) meeting online.
Slidesets and reports will be shared with Web3D Consortium members, we hope to see those announcements soon. Repeat topic for next week.
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2. Overall specification work planning.
As everyone knows, we are steadily pressing ahead with X3Dv4. This certainly has many parts but all the building blocks are lining up well.
Our best summary remains the diagram
X3D Graphics Standards: Specification Relationships
http://www.web3d.org/specifications/X3dSpecificationRelationships.png
File encodings: XML, ClassicVRML, Compressed Binary, EXI, JSON.
Programming Languages: JavaScript (EcmaScript), Java, C++/C#/C, Python.
Each appears do-able, with various practitioners actively engaged, and increasing maturity across the board.
Time sensitive: EcmaScript deadline is imminent, only 6 months left to produce ISO DIS text. Java is co-developing and can follow shortly thereafter.
Projects need to be started for each of the others. CD text (similar throughout) can be prepared in tandem, this is critical path. New Work Item Proposal (NWIP) to follow with eventual Web3D Consortium review & approval of Committee Draft (CD).
Suggested approach:
- Rank by maturity and prioritize (next week).
- Getting one of each done well will help all the others proceed.
- Develop Plan of Action Milestones (POAM).
- We should have 1-2 active specification documents at any given time.
- Will alternate or work in tandem on file-encoding and programming-language documents.
- Further member participation can speed these efforts. We will succeed regardless.
Planned changes to Specification Relationships diagram:
- up-arrow from H-Anim to CGRM is unnecessary.
- HAnim now has 2 parts in DIS (Architecture and Motion Animation), with Facial Animation also beginning to mature.
- glTF file extensions are recommended as .bin (binary) and .gltf (for json) with .glb (combined).
- no need for .x3de, rather decompressing .exi becomes .x3d (and vice versa).
- perhaps no need for .x3dj but we can follow lead of JSON Schema (when that gets finished/approved).
- TBD checkpoint: .x3de and .x3dj likely to be determined by MIME type, otherwise inspection of file contents must occur.
- X3D Unified Object Model (X3DUOM) will likely become informative annex in X3D v4.0, also generated for other versions.
- Note draft v4.0, v4.1 in X3D Architecture.
- Still unclear is whether X3D DOM integration is part of Architecture or becomes a new file-encoding specification.
- glTF 2.0 is final, no longer planned/proposed.
Next component to be added: Projective Texture Mapping (PTM) by Dr. Kwan Hee Yoo, topic for next week.
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3. Khronos meetings at SIGGRAPH 2018:
https://www.khronos.org/events/2018-siggraph
"Find all of the presentations and other assets from this event in our Video and Presentations Library."
https://www.khronos.org/developers/library/2018-siggraph
SIGGRAPH 2018 WebGL BOF
https://www.khronos.org/webgl/wiki_1_15/index.php?title=Presentations&diff=2581&oldid=2577#SIGGRAPH_2018_WebGL_BOF
also
2018 glTF Meetup, June 2018 at Microsoft
https://www.khronos.org/developers/library/2018-gltf-meetup
also
Khronos at Web3D 2018
https://www.khronos.org/events/web3d-2018
Neil Trevett Keynote
https://www.khronos.org/assets/uploads/developers/library/2018-web3d/Web3D-Keynote-Poznan-2D_Jun18.pdf
Note differences in glTF player renderings on slide 8 - these are circa SIGGRAPH a year ago. He notes:
"glTF considering optional, standardized environment and lighting guidelines for consistent default appearance between viewers".
Vince reports from discussions with Leonard that there is no provision for backwards compatibility between glTF 2.0 and glTF 1.0. If a minor-version 2.1 appears, it will have some degree of backwards compatibility.
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4. X3D strategy for glTF support of physically based materials and consistent lighting models.
Our forwards (and backwards) compatibility motivations include:
a. Ability to inline glTF models within any X3D scene.
b. Take advantage of glTF geometric compression as a natural progression from prior efforts using Fraunhofer SRC approaches.
c. Add Physically Based Materials to X3D’s native Appearance and Material capabilities.
d. Correspondingly improve X3D lighting model to match precisely defined lighting equations. Ensure that X3D lights are similarly evolving in a backwards-compatible manner.
e. Confirm compatibility with other advanced X3D rendering techniques such as volume visualization, shaders, parametric surfaces, etc. Modify X3Dv4 draft specifications as needed for global coherence.
f. Establish a set of conformance examples to demonstrate correct rendering, thus permitting X3D players and authors to confirm consistent visual presentation of advanced material properties. (I expect that visual correctness will be a strict requirement in multiple application domains, for example medical use.)
g. Demonstrate compatibility with mainstream tools and programming environments. For example, extending Tobias Franke’s Unity3D to X3D exporter will help us confirm that X3Dv4 representations are well defined and well implemented. Online at https://github.com/thefranke/unityx3d
h. Be better informed as we track and demonstrate rapidly progressing advancements in 3D printing and 3D scanning. We are observing that new aspects of physical material properties are being specified in those domains. For near term we expect to support experimentation through carefully defined metadata sets. For both domains, application of compression algorithms to meshes, point clouds and volumes will provide further worthy challenges.
My expectation is that such a disciplined approach will encourage mutually beneficial progress in all directions: both down towards hardware (Khronos arena), broadly in rendering on diverse devices, and upwards towards any Web application (where Web3D is relentlessly pressing ahead). All pushback, insights and strategic coordination will continue to remain welcome as this long journey continues.
And so... whew! A lot to consider. Meanwhile (as always) the details matter.
We look forward to carefully reviewing all of the SIGGRAPH glTF forum presentations, we will revisit and share links when possible. We will further schedule recurring X3D Working Group meetings that focus on glTF, materials and lighting (approximately monthly) in order to climb this necessary mountain well.
Several people have indicated that our current Appearance/Material is a compatible subset of the glTF physically based materials. This will be an important aspect of X3D v4 development.
It remains to be seen how accessible and repeatable glTF code will be for the variety of X3D players in active development. IMO the need to upgrade the X3D lighting model is so important that we absolutely need to proceed. Presumably such compatibility will further help us when we go to Virtual, Mixed and Augmented Reality rendering techniques in X3D v4.1.
Prior comparison work:
Daly Realism blog, glTF/X3D Comparison
http://realism.com/blog/gltf-x3d-comparison
X3D Working Group: glTF X3D Features Comparison (3 NOV 2017)
http://www.web3d.org/sites/default/files/page/X3D%20Version%204/glTfX3dFeaturesComparison.pdf
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5. Selected SIGGRAPH BOF and show highlights.
Will discuss next week, hopefully with everyone's slidesets online and attached to each event page.
Web3D at SIGGRAPH 2018
http://www.web3d.org/event/siggraph-2018
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6. Web3D Conference planning 2019, 2020.
Discussions in progress for co-locating Web3D 2019 with SIGGRAPH in Los Angeles (28 July - 1 August), and Web3D 2020 overseas in Asia.
SIGGRAPH 2019
https://s2019.siggraph.org
Note that 2020 is the 25th anniversary of the Web3D Conference - big wow!! We are looking at potential special events at SIGGRAPH 2020 in Washington DC, 19–23 July 2020.
ACM SIGGRAPH Announces 2020 Conference Chair, Location
https://globenewswire.com/news-release/2018/01/22/1298822/0/en/ACM-SIGGRAPH-Announces-2020-Conference-Chair-Location.html
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7. Regular expressions (regexes) updates.
Continuing progress, getting closer. Have regularized patterns and continuing refinement underway. New update published yesterday.
Extensive testing is performed with each release using the X3D Example Archives, a Java X3DJSAIL unit test program for each X3D data type, and multiple unit tests online at regex101.
X3D Regular Expressions (regexes)
http://www.web3d.org/specifications/X3dRegularExpressions.html
X3D n-Tuple Regular Expression (regex) Patterns
http://www.web3d.org/specifications/X3dRegularExpressions.png
Currently the regexes are being developed and updated as part of the X3D v4.0 schema. Am expecting to deploy them back into X3D Schemas v3.0 through 3.3 sometime in the next month. All feedback welcome.
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8. All other business.
a. Had several interesting discussions with Mitch Williams who has been doing a lot of X3D Java work for GearVRF.
https://github.com/Samsung/GearVRf
"The GearVR framework(GearVRf) is an Open Source VR rendering library for application development on VR-supported Android devices."
b. Will look at X3D Prototype Expander again... the design pattern to apply (Extern)ProtoDeclare definition to a ProtoInstance and then create a proto-less X3D model tree.
We got at least one converter to about 80% complete before, am thinking that this might be a straightforward capability to write using X3DJSAIL. Prior links include
[x3d-public] What to do with ViewpointNode and NavigationInfoNode in prototype expander
http://web3d.org/pipermail/x3d-public_web3d.org/2016-June/004951.html
[x3d-public] Prototype Expander, Question on design of instance expansions
http://web3d.org/pipermail/x3d-public_web3d.org/2016-July/004982.html
[x3d-public] Prototype Expander, Question on design of instance expansions
http://web3d.org/pipermail/x3d-public_web3d.org/2016-July/005017.html
and
X3D Example Archives: X3D for Web Authors, Chapter 14 Prototypes, Material Modulator Prototype Expanded
https://x3dgraphics.com/examples/X3dForWebAuthors/Chapter14Prototypes/MaterialModulatorPrototypeExpandedIndex.html
description="Provide example for expansion of a MaterialModulator as regular X3D nodes, rather than a ProtoDeclare/ProtoInstance combination. MaterialModulator mimics a Material node and modulates diffuseColor field as an animation effect."
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Many thanks for all the many public contributions over the past few weeks. Totally impressive.
Having fun with X3D! 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
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