[x3d-public] X3D minutes 22 May 2020: propagating X3D4 specification changes, enter geospatial Mantis issues

[Don Brutzman]

Attendees Anita Havele, Vince Marchetti, Mike McCann, Dick Puk, Doug Sanden, Don Brutzman.  Regrets Nicholas Polys.

Confirmed: no member-only information included in these minutes.

We will meet at our regular time, 0800-0930 pacific Friday 8 May 2020.  Zoom room coordinates are now linked via the Web3D Calendar. Note that all Web3D zoom conference lines are now protected by password.

[1.1] Web3D Teleconference Information
        https://www.web3d.org/member/teleconference-information

[1.2] Web3D Calendar
        https://www.web3d.org/calendar/month
        https://www.web3d.org/calendar/x3d-graphics-working-group/2019-09-13t150000-2019-09-13t163000-2019-09-20t150000-2019-09

[1.3] [x3d-public] X3D minutes 8 May 2020: renewed HAnim progress, X3D4 geospatial assessment
       http://web3d.org/pipermail/x3d-public_web3d.org/2020-May/012641.html

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2. *Outreach*

Anita reported and led discussion on good progress by Web3D 2020 program committee, more to follow next week.

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3. *LayerSet issue analysis*

We discussed process for X3D4 specification updates, using this node as an example.

[3.1] Mantis 1292: numbering of z order of layers in LayerSet
       https://www.web3d.org/member-only/mantis/view.php?id=1292

Core issue in X3D Architecture is fixed as follows, and noted there:

[3.2] 35.4.2 LayerSet
       https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/layering.html#LayerSet

   SFInt32 [in,out] activeLayer 0 (0,infinity)
to
   SFInt32 [in,out] activeLayer 0 [0,infinity)

However we noted that further reconciliation and alignment with HTML5 Recommendation may be needed.  Nicholas has action on this issue.

In general, next steps to propagate X3D4 change information:

a. X3D Tooltips provide publicly accessible summaries, warnings and hints.

[3.3] X3D Tooltips LayerSet, activeLayer
       https://www.web3d.org/x3d/content/X3dTooltips.html#LayerSet.activeLayer

b. Mantis issues requiring nontrivial browser changes are usually marked as severity "MAJOR", otherwise MINOR.

c. We plan to create an errata list "Summary of X3D4 Changes" at some future date (maybe June) based on that issues list.

d. Strict validation by Schema/DOCTYPE and signatures in X3DUOM are also updated.

e. X3DUOM changes get applied to Java, Python, JSON and Turtle implementations.  Boom!

f. As illustrated in current HAnim2 work in progress, rules for X3D Schematron and automatic fixes in X3D-Tidy are also added wherever possible.

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4. *Geospatial Issues*

a. GeoLOD.  Potential issue is that when traversing Many Many layers (e.g. space to ground), very inefficient.  However GeoLOD is OK if going from aircraft altitude to ground (a handful of layers) it is OK.  Significant effort to re-architect not desired.  More performant measures are possible using SRC compression of binary mesh (gltf -> glb) with X3DOM specialty nodes that are already under consideration in other X3D4 work.  Geospatial positioning of such prepared meshes can occur using other X3D Geo nodes, we expect further geospatial implementation and workflow efforts to continue.  Lots of flexibility currently exists to enable meaningful geospatial terrain preparation using existing (and improving) tools.

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b. Navigation.  We briefly discussed whether further review is needed.  Requested.

[4.1] Mantis 1301: check geospatial navigation to see if NavigationInfo modes are sufficient
       https://www.web3d.org/member-only/mantis/view.php?id=1301

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c. Edge normals to succinctly allow stitching together large quads without "seam" visual artifacts. Apparently not a problem with SRC-compressed mesh.  Issue not entered.

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d. Dick and Don will talk to Farid Mamaghani to see if any SEDRIS capabilities of interest need to be considered.

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e. OGC CityGML has different characterizations of level of detail (building tops, frames, etc.)  Such information might be captured as MetadataSet information... Similar aspects might be considered for Smart Cities.  We discussed and will avoid proposals to add new features into X3D until needed.  "Low-hanging fruit" that is simple to implement and opens the door to further interoperability can always be proposed.

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f. Entered previous discussion for geoSystem refactoring as Mantis issue.

[4.2] Mantis 1302: geoSystem is difficult to define and parse, consider alternative approach
       https://www.web3d.org/member-only/mantis/view.php?id=1302

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g. Entered issue for WebMercator support.

[4.3] Mantis 1303: optional support for WebMercator datasets
       https://www.web3d.org/member-only/mantis/view.php?id=1303

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h. Mike requested to review apparent completion of

[4.4] Mantis 741: 25.3.6 GeoOrigin - removing deprecation status
       https://www.web3d.org/member-only/mantis/view.php?id=741

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i. Deep discussion of extended spatial reference frames.

Doug is considering implementing in FreeWrl.  That would certainly demonstrate feasibility!  If this is something he does, we will add it to candidate functionality list X3D4.

Dick agreed to write up a Mantis issue.

Further discussion planned next week.

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Thanks everyone for today's excellent progress.

and of course: have 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