[x3d-public] X3D meeting minutes 3 FEB 2019: X3Dv4 mantis github specification changes, glTF plans, MetadataSet

Brutzman, Donald (Don) (CIV) brutzman at nps.edu
Fri Feb 8 10:18:55 PST 2019


0. Attendance.  John Carlson, Anita Havele, Vince Marchetti, Nicholas Polys, Dick Puk, Don Brutzman.

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

We meet today, as usual, 0800-0830 pacific.  To join the teleconference:

	Web3D Teleconference
	http://www.web3d.org/member/teleconference-information

The X3D Graphics Working Group addresses all X3D specification issues and coordinates the technical development of future improvements.
http://www.web3d.org/working-groups/x3d

Each week we report out both public and member-only information - membership has value.  To become a Web3D Consortium member:

	Join the Web3D Consortium
	http://www.web3d.org/join

==================================

0.5 Good discussion on Library of Congress efforts for cultural heritage.  Please look at the survey and enter your project.

Nicholas is our POC, the thread is on working-group mailing list.

	[x3d] Survey about 3D format usage   Nicholas Polys
	http://web3d.org/mailman/private/x3d_web3d.org/2019-February/007424.html

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0.6 Upcoming announcements in preparation.

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

b. W3C Immersive Web Meeting with WebXR announcements, following a successful meeting in Mountain View CA at Samsung Research USA.

	http://www.web3d.org/event/w3c-immersive-web-meeting

c. Semantic 3D Workshop accepted at EuroGraphics 2019

	http://semantic3d.org/workshop

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1. Mantis issue tracking.  Member access.  We will discuss procedures and visit some issues.

	Web3d.org > login > MEMBERS > RESOURCES > MANTIS ISSUE TRACKER > (second login) > (revisit link) > View Issues
	http://www.web3d.org/member-only/mantis/my_view_page.php

Go to "Main" then see announcement

	Values for the fields Reproducibility, Severity, and Priority, and
	explanations of the meanings of the issue statuses are defined in
	Mantis Definitions
	http://www.web3d.org/member/mantis-definitions

	The workflows for Mantis issues, including illustrations, are described in
	Mantis Workflows
	http://www.web3d.org/member/mantis-workflow

Second announcement

	The existng Mantis Status' are used as follows:

	new -- Newly entered comments
	feedback -- Comment needs feedback (either individual or group)
	acknowledged -- WG will consider this comment
	confirmed -- WG has decided to accept this, need to assign an individual
	assigned -- This comment has been assigned to an individual for write up
	resolved -- This comment is to go into the next ISO document
	closed -- This comment has been incorporated into a document submitted to ISO

	Once you have written up the issue, please do the following:
	1) Set the status to 'resolved'. You do not need to enter a reason.

Also please review process diagrams on the Workflow page above.  Once again thanks to Roy Walmsley for preparing these.

Mantis tags: v4.0 or X3Dv4, X3Dv4.1, etc.  Planning to match conventions on web pages: X3Dv4 X3Dv4.0 X3Dv4.1 for consistent searchability within Mantis.

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2. Github specification editing.  Member access, by request.  We will discuss procedures.

	Github: Web3D Consortium, X3D and H-Anim specifications
	https://github.com/Web3DConsortium

We reviewed membership status.  16 participants.

Not changing v3.3 documents, even if trivial.  If we ever need to issue errata we can do so, and github record of commit changes is very helpful.

Web version is "ground truth" to confirm you are right version of HTML/CSS/image content.  Very helpful way to confirm whether you have the right version of content on your system.

Upcoming work in github.

a. Need to cleanup HTML to match HTML4 and matching compliance (avoiding inconsistencies) with HTML 5.  This keep s us consistent with ISO guidance, since not all nations have latest/greatest browsers.  We have HTML Tidy tool instrumented now as part of build script.

b.  CSS for editors comments.  These are pretty mature already and can be used to indicate editors comments, additions, deletions, proposed/approved etc.  These will be applied more uniformly across the specifications and covered in a future meeting.  Making diff changes visible will be helpful.

c. build.xml scripts are present to assist in repetitive editors tasks such as HTML Tidy checks, creating zip files (both Web3D and ISO version).

d. pull requests: describe.  we're working on supporting pull requests but not yet there.  We expect to support that at some point, but only with respect to editing tasks.  The functional descriptions and intent for spec changes will all be captured on working-group or public email, then collected and tracked in Mantis, then applied in github specification.

A big value of Web3D Consortium membership is this clear process that results in clear changes to the X3D Specification series that are well documented, deliberate, carefully crafted results.

*postscript* am hoping to simplify some of the urls by removing spaces and special characters.  Will give advance warning since this effects all checkouts.  Feedback welcome.

==================================

3. CAD Design Printing Scanning changes: PointProperties

We discussed changes and next steps from this week's teleconference.

	[cad] DPS WG call Thu Feb 7 response includes .pdf snapshot of change
	http://web3d.org/mailman/private/cad_web3d.org/2019-February/001077.html

Shape component edited, TODO block has been inserted for working group improvements.  Archival records of all suggestions are indeed recorded in email and Mantis so that all knowledge and insights are captured/compared/correlated/converged.

For example, note that original proposal was by Christophe Mouton ~2007 and implementations exist in Xj3D and (kinda) in Instant Reality.  So clear definitions now in draft spec (mediated by working group) can lead directly to next steps: implementation in X_ITE/X3DOM, implementation in other software, creation of example scenes, validation tools, etc. etc.

So here we are - editing the X3D version 4 specification, with all due diligence!  Onward we go.  8)

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4. Humanoid Animation (HAnim) specification changes.

*Member only information*

Please see the X3D Working Group thread on x3d at web3D.org for the rest of this topic.

	http://web3d.org/mailman/listinfo/x3d_web3d.org
	http://web3d.org/mailman/private/x3d_web3d.org/2019-February/thread.html

==================================

5. glTF.  Much excellent recent progress.  We discussed next steps for Mantis and github.  Email threads:

	http://web3d.org/pipermail/x3d-public_web3d.org/2019-February/010001.html

	http://web3d.org/pipermail/x3d-public_web3d.org/2019-February/010008.html

Briefly discussed issue of representation
(a) glTF as "black box" that gets rendered, or
(b) expansion of glTF internals as X3D.

Certainly understanding the correspondences between ID/labeling, and correspondences between 3D functionality, is centrally important. Ongoing implementation work by Andreas Timo Michalis Leonard and others is showing that such correspondences are indeed possible.  Not yet clear where we should "draw the line" regarding internal glTF access by X3D, along with agnostic/suggested/recommended/required conversion guidance.

Future Khronos intent might have a bearing here as well, but please note our task at hand is to support glTF 2.0 in X3Dv4.0.  Internal editing of content is not apparently a supported feature; so X3D SAI access to glTF internals might not last over long term.  We must proceed carefully.

It would certainly be helpful for authors to be able to reach into a glTF model and get PBR material values, which might then be DEF/USE reused in an X3D scene for model consistency.

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.

Next-step X3D glTF actions of Mantis summaries and specification placeholder is deferred for upcoming call when Michalis can be present.

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6. MetadataSet and /metadata/ fields.  Much excellent recent discussion.  We discussed the issues and alternatives.  Email thread:

	[x3d-public] gltf metadata: X3Dv4 MetadataSet design issue
	http://web3d.org/pipermail/x3d-public_web3d.org/2019-February/010020.html

Summary: changing MetadataSet to have only MFNode /metadata/ field.  This simplification would eliminate confusion/verbosity that arises from having a MetadataSet /value/ field.  This will be much less error prone, not eliminate any existing functionality, and further simplify MetadataSet for all encodings and language bindings.

Concern: whether capability being lost that is important, i.e. providing metadata about a parent MetadataSet. (This is an agreed-upon capability.)  More specifically then, is there a need to interpret via separate fields to disambiguate the roles of contained metadata nodes?  Multiple pros and cons, in-depth discussion.

John noted that this entire issue may impact Prototype design slightly as well - agreed.

Another possible alternative: change XML encoding for MetadataSet to have default containerField='value' instead, without changing specification or X3DUOM or existing implementations.

If we keep the separate MFNode /value/ field, a related issue (noted in the thread) is renaming it as /children/ leads to better consistency with other design patterns.

	X3D Scene Authoring Hints, containerField: Variations from containerField defaults
	http://www.web3d.org/x3d/content/examples/X3dSceneAuthoringHints.html#containerFieldVariations

Great discussion, very helpful.  Will create mantis entry with summary of alternatives and links.

Request concurrence that everything is well stated...  yes, agreed.

Proceeding to changes and testing via X3Dv4 schema, X3DUOM, X3DJSAIL?  Not yet, we still need to consider this issue and reach consensus on final resolution.

Very encouraging!  We have 2-3 alternatives, and are much closer than ever before to achieving an improvement over X3Dv3.3 when handling large blocks of structured metadata.

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7. Next and upcoming meetings.

a. Continuation of this week's issues into Mantis and then X3Dv4 draft specification.

b. X3Dv4 pages review: any comments or additions?

	http://www.web3d.org/X3D4
	http://www.web3d.org/wiki/index.php/X3D_version_4.0_Development

c. X3Dv4 design review: Web3D 2017 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

d. Next additions we will pursue: Projective Texture Mapping PTM and shadows.

==================================

Thanks for all contributions today, very productive.  Have fun with 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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