[x3d-public] X3D meeting 10 May 2019: Physically Based Rendering going into specification, X3Dv4 implementation updates

Brutzman, Donald (Don) (CIV) brutzman at nps.edu
Fri May 10 10:14:10 PDT 2019

1. Regular meeting planned for Friday 9 MAY 2019 (08-0930 pacific) to focus on:

Attendees: Anita Havele, Michalis Kamburelis, Vince Marchetti, Nicholas Polys, Dick Puk, Don Brutzman.

- Web3D and SIGGRAPH 2019 preparations
- Physically Based Rendering PBR Materials and Lighting

Group review: All information in these minutes is suitable for public release.  Member-only information is posted separately.


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

We meet regularly on Fridays 0800-0930 pacific.  To join the teleconference:
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The X3D Graphics Working Group addresses all X3D specification issues and coordinates the technical development of future improvements.

Each week we report out both public and member-only information - membership has value.  To become a Web3D Consortium member:
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Information inputs are always welcome.  With much X3D activity occurring there is typically plenty to review each week, ensuring that our progress continues to be clearly recorded and communicated.


2. *Prior meeting minutes, recent highlights*

At this point we discuss recent meetings and current developments.

	[x3d-public] X3D minutes 3 MAY 2019: C/C++/C# and Python progress, PointProperties validation for X3Dv4

Note that definition of XML Schema/DTD/Schematron/Tooltips led to some refinements of PointProperties spec prose.  Hoping someone can check the Mantis bug and GitHub document, as noted there.

Also of broad interest:


	[x3d-public] X3D Python availability, planning for releases at Web3D 2019
	"Incredibly It Is All X3D."

Agenda and topic review:

a. A great role for someone will be to help with maintaining X3Dv4 implementation status.  A lot is happening - this is a great way to keep track of what is going on.

b. Do we need to have a volunteer to represent Web3D and X3D in the WebXR group?  Seems like a valuable role for someone, especially if interested in X3Dv4.1 efforts.  Having a 5-minute weekly update on WebXR activities might be useful. Web3D liaison to W3C for WebXR would be a formal position.

c. Dick reported that ISO has begun responding to Web3D Consortium comments, provided via SC24 and JTC1.  Good to hear progress is occurring.


3. *Finalize Web3D 2019 submissions*

Brief discussion to resolve final questions.

a. X3D Semantic Web Workshop.  We decided to reserve an hour on morning of Friday 26 JUL 2019 on the workshop day immediately preceding the formal Web3D 2019 Conference.  Registration will not be required, attendance is open, a zoom channel will be provided for both audio and video.

b. X3D Quickstart.  A 30-minute summary for new attendees will be provided based on AMIA tutorial.  This is a good opportunity for someone other than usual suspects to provide a welcoming big picture.

c. X3Dv4 Implementations Tutorial. This would be a summary of all implementation assets for X3Dv4.  Prior knowledge of X3D is expected to follow what is saying.  The tutorial will start with a summary from past Web3D conferences with a brief overview of various specifications involved, and the X3Dv4 design process.  Wherever possible the primary implementer will provide summary slides, otherwise Don will cover it.  Expected outcome is that participants and those using the tutorial afterwards will be to focus, engage and use whichever aspect of X3Dv4 they are interested in.  This sets the stage for continued cooperative implementation work through December, which is the deadline for submissions to X3Dv4.

We decided to request 60-90 minutes to provide this tutorial.  Probably best is during the conference for broadest impact, Friday workshop day is acceptable too.  Conference chairs will decide whether to accept and when it might appear in the extended program.

d. SIGGRAPH BOF draft prose, separate editing continues:

"Use cases for 3D publishing on Web are powerful.  The Web3D Consortium will highlight ongoing online interactive visualization progress across multiple industry domains through X3D and other open standards: glTF, WebGL, Open Geospatial Consortium (OGC), Blender, X3DOM/X_ITE communities."

TODO submit on Web3D 2019 website.


4. *Include PBR Physically Based Rendering in X3Dv4 Architecture specification*

Goal outcome for today: define list of sections for X3Dv4 Architecture specification draft, enabling editing work to begin.

Michalis Kamburelis updated us on his extensive work in this area:



a. *What is PBR and why do we want it in X3D?*

Discussion summary: essential reading.  This motivation and graphics background is an excellent synthesis of in-depth mailing discussions JAN-MAR 2019.


b. *How to add PBR to X3D?*

Discussion summary: this technical rationale for integration is again based ony in-depth mailing discussions JAN-MAR 2019.  At that time the X3D Working Group decided to proceed with adding PBR to X3Dv4.


c. *Specification changes, to include PBR and related features*

Discussion summary:  this is a roadmap for implementers and specification editors.

- The "first..fourth wave" provides a great way for implementers to see a path for progressively adding such capabilities to their software.
- Lighting equations and descriptions are also needed in the specification.
- Phong lighting (X3Dv3) can coexist with PBR rendering (added in X3Dv4) for different geometries being shown in the same scene.
- X3Dv4 would not implement new lighting by default, but only apply it if explicitly indicated in a scene.
- Rephrase: changing the header of an existing v3 model to X3Dv4 would not change rendering and appearance.
- Michalis plans to begin comprehensively implementing this work in the near future, following the waves in order.
- We are hoping that Andreas is implementing effectively already in X3DOM, and comparing to X_ITE for compatibility.
- We therefore expect that three implementations can emerge and converge over the next half year: Castle Game Engine, X3DOM and X_ITE.


d. *We foresee changing the following components and clauses in X3Dv4 specification*

4 Concepts
- Consider if this modifies architecture sections there
- update Interface Hierarchy diagram (same for any new nodes)
- perhaps no changes needed

11 Rendering component
- perhaps no changes needed

12   Shape component
12.2 Concepts
12.3 Abstract types
12.4 Node reference
12.5 support levels

17  Lighting component
17.* (similarly all components)

18  Texturing component
- multiple additions expected

24 Environmental effects component
- perhaps no changes needed

31  Programmable shaders component
- perhaps no changes needed

33  Texturing3D component
- perhaps no changes needed

34  Cube map environmental texturing component
- perhaps no changes needed

41  Volume rendering component Lighting
- review original design, some advancements may be advisable
- perhaps no changes needed

43 Projective Texture Mapping Component
- to be reviewed Lighting

I  OpenGL shading language (GLSL) binding
J  Microsoft high level shading language (HLSL) binding
K  nVidia Cg shading language binding
- perhaps no changes needed


e. *Next steps*

- Wave 0: begin modifying draft X3Dv4 specification
- Encourage browser builders to begin adopting waves
- Create example scenes for review clarity, development testing, and interoperability checking
- Review waves progress in order, working-group review at approximately monthly intervals

We thanked Michalis for this tremendous work.  Here we go!


5. *Recent and Upcoming Events*

*Web3D 2019 Conference registration is open* hooray!  Discount provided for ACM members.


Web3D and SIGGRAPH registration independent of each other.


Communications team meets weekly to continue promoting Web3D, X3D and HAnim.


6. *References and Resources*

	X3Dv4 Implementations Status


	X3Dv4 Development page

	X3D Specification Relationships

	Mantis Issues (requires member login, twice)

	Web3D Specifications on Github: X3D (members can request access)


7. *Upcoming topics*

Next week: TBD (Don traveling)

Topics list:

a. *Projective Texture Mapping (PTM) component*
- Mantis issue 1255 created for keeping track of status.
- TODO Add zip of spec/examples/information that has been submitted on mantis issue
- Prose already present in github components directory as ProjectiveTextureMapping.html
       43  Projective Texture Mapping Component
- TODO Add example scenes to X3D Basic Examples Archive
- TODO List existing implementations, then issue call for additional implementations.

b. *Annotation Component*
- Much work already accomplished.  Renewed review in Design Printing Scanning (DPS) group.
- Time to land any existing draft prose in github specifications, and review what work is occurring.
- splitting out positioning aspects of 3D space as opposed to 2D screen space,
- refactoring of earlier concepts,
- creation of prototypes.
- also consider HTML5 techniques as an alternate way of accomplishing positioning aspects of 2D screen space.
- even the simple creation of node interfaces with field definitions is a good way to begin incremental improvement.
- ready to add an improve initial prototype.

c.*X3D Architecture Design and Event Passing, compare implementations*
- Specification writeup planned late May.
- how have X3DOM and X_ITE each implemented events?
- What differences exist?
-- Are ROUTE connections consistent?
-- X3DOM is still missing some important/simple Event Utility nodes - is there a problem?
-- Highlight how does syntax disambiguate handling of HTML5 Script and X3D Script?
-- Reviewing our tagging of Mantis issues as #X3Dv4 for completeness.
-- Ensure that goals and concepts on relationships between HTML5 and x3D are clearly expressed.

d. MetadataSet containerField implementation efforts, Mantis issue resolution

e. Tagging and prioritizing Mantis issues.

f. Numerous things to drive to completion, who is doing what? Now listed on X3Dv4 Implementations page.

g. Sound and Audio improvements


No major showstoppers are noted, rather we continue getting closer to a comprehensive X3Dv4-HTML5 architecture and specification each week.

Have fun lighting up 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

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