[x3d-public] X3D meeting minutes 8 APR 2022: C/C++/C#, binding events under inactive branches of Switch or LOD

Fri Apr 8 09:54:13 PDT 2022

Attendees: Anita Havele, Nicholas Polys, Dick Puk, Doug Sanden, Don
Brutzman.

We successfully held our regular weekly X3D meeting today, 08-0900 pacific.
Agenda topics follow.

*
https://us02web.zoom.us/j/81634670698?pwd=a1VPeU5tN01rc21Oa3hScUlHK0Rxdz09 
*	https://zoom.us/j/148206572  Password 483805 
*	https://www.web3d.org/member/teleconference-information 

1.	New weekly agenda item:  review ballot items from INCITS H3 (U.S.
Standards Body) and W3C.

We reviewed procedures and voted on two ballots for US. National Body.

2.	Web3D 2022 Conference preparations are progressing well.  Call for
Papers is now approved and available!

*	http://web3d.siggraph.org
*	https://web3d.siggraph.org/web3d-2022-call-for-papers

Web3D 2022:  27th International Conference on 3D Web Technology will be
November 2-4.  Dates of interest:

Submission July 23rd, 2022

                              Papers

                              Tutorials

                              Workshops

Notification Sept. 15th, 2022

Final version  01/10/2022

3.	X3D Scene Access Interface (SAI) draft specifications for C, C++, C#
language bindings available for comment.

*	[x3d-public] X3D C/C++/C# CD texts approval for ISO submission -
public comments requested
*
https://web3d.org/pipermail/x3d-public_web3d.org/2022-April/017073.html
*
https://www.web3d.org/specifications/ISO-IEC19777/ISO-IEC19777-3v3.3-CD  C
*
https://www.web3d.org/specifications/ISO-IEC19777/ISO-IEC19777-4v3.3-CD  C++
*
https://www.web3d.org/specifications/ISO-IEC19777/ISO-IEC19777-5v3.3-CD  C#

Our plan is to proceed with international review of version 3.3 of these
specifications, then upgrade to 4.0 once X3D4 Architecture is complete and
then X3D4 SAI 19775-2 abstract specification is similarly updated.

4.	Our current top priority is resolving Mantis review issues, in order
to finalize X3D4 Architecture for Draft International Standard submission to
ISO.

*
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/
Architecture.html

a.	PointProperties markerType: does it look OK?

*	[x3d-public] X3D minutes, Friday 1 APR 2022: glTF X3D4 video, mantis
issues, PointProperties markerType
*
https://web3d.org/pipermail/x3d-public_web3d.org/2022-April/017049.html

*	X3D4 Architecture, Shape component, 12.4.7 PointProperties
*
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-CD1/Part01/
components/shape.html#PointProperties

We had insightful discussion, the following was added to Mantis.

*	Mantis 1393: 12.4.7 PointProperties missing markerType field
*	https://www.web3d.org/member-only/mantis/view.php?id=1393

Where is point sprite (or point splat) proposal?

Is this aligned satisfactorily/sufficiently with common practices for point
visualization? Seems compatible with other symbology.

Can we
- control transparency? (background fully transparent, no control provided)
- control color? (yes, by Material or Color node with indices/order)
- specify other images/icons/glyphs/sprite? (yes, but requires coordination)

If accepted, needs mention in 11.4.12 PointSet

If accepted, needs integration with prior/existing work (including X3DOM
implementation)

If not accepted, needs to be deferred to X3D4.1

Proposing additional markerTypes to ISO corresponding to these other
approaches is a useful option to us.

Goal: resolve during April 2022.

b.	Mantis 1192: 07.2.2 Bindable children nodes - Undefined results if
bindable node is under Switch or LOD is problematic

https://www.web3d.org/member-only/mantis/view.php?id=1192

Spec sayeth:
"The results are undefined if a bindable node is bound and is the child of
an LOD, Switch, or any node or prototype that disables its children."

This leads to all manner of inconsistent problems among scenes. It also
means that Inline node (which may or may not include bindable nodes) has
undefined behavior under LOD/Switch/etc.

As a result, in addition to indeterminate X3D browser behavior, it means
that X3D scenes are not fully composable. That is contrary to X3D design
objectives.

Different prose and deterministic guidelines is needed in this section that
provides clear rules for binding/unbinding nodes when they become active
within LOD/Switch/etc. Small adaptations to current binding rules can likely
address this problem satisfactorily.

Request review and comment on the following suggested resolution.  The
intent is to reinforce author modeling choices over independent browser
optimization.

    "Sending a set_bind event to a bindable node that is a child of a Switch
node is typically ignored, respecting the selection logic of the parent
Switch.

    Since different levels of an LOD node are intended to be visually
similar and only varying in terms of level of detail, sending a set_bind
event to a bindable node that is a child of an LOD typically binds that node
and also activates the corresponding level in the LOD.

    Even if event behavior is ignored, such occurrences may be reported via
a console (if available)."

Group review comments, added to Mantis 1192:

*	For Switch, avoid "typically" and make phrasing unambiguous that the
autoselection occurs.
*	For bindable nodes, note that they remain active on their respective
binding stack.
*	If you have a bound Viewpoint under a selected Switch child, and a
different Switch child becomes selected, is that current Viewpoint unbound?
We would expect so.

If this is too complex, we should defer to X3D4.1. This nevertheless is a
reduction of the "browser response is undefined" space. Let's get this
potential refinement sorted out as best possible, then assess if resolves
the issue satisfactorily, and then approve or else defer to 4.1.

Nicholas noted prior work on "Plans for Merging X3D AR Proposals" proposal,
we added this to Mantis as deferred work for X3D4.1 specification.

*
https://www.web3d.org/wiki/index.php/Plans_for_Merging_X3D_AR_Proposals
*	https://www.web3d.org/member-only/mantis/view.php?id=1394

Have fun with X3D!  8)

all the best, Don

-- 

Don Brutzman  Naval Postgraduate School, Code USW/Br        brutzman at nps.edu
<mailto: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

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