[x3d-public] X3D minutes 6 SEP 2019: DICOM discussion, overview diagram review, ISO meeting highlights, API progress, defer STL/OBJ support

Brutzman, Donald (Don) (CIV) brutzman at nps.edu
Fri Sep 6 09:51:45 PDT 2019

Dick and I traveled to Takamatsu Japan all last week for annual ISO standards committee SC24 meeting.  Totally productive!  8)

Here are minutes for X3D Working Group meeting Friday 6 SEP, 08-0930 pacific.  (Connection information below.)

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

Recent meeting minutes:

* [x3d-public] X3D Working Group minutes 16 AUG 2019: PointProperties/PointSet, IIIF 3D, glTF, ISO preps

* [x3d-public] X3D Working Group minutes 21 AUG 2019: glTF X3D specification Plan Of Action Milestones (POAM)



0. Progress and problem reports.  What else is new?!  8)

a. Email thread on

	for 3D Manufacturing and Virtual Reality BY MIDNIGHT SUNDAY, OCTOBER 19, 2019

Comments are already started and will continue to be added regarding Web3D response.

	DICOM Sup 208 Public Comments Draft

What we would consider supporting "metadata" is expected to be covered already by well-defined metadata contained within the DICOM format itself.  The OBJ model would get embedded in the DICOM stream.

The slideset and document in Meghan McCarthy has many excellent good points in it, worthwhile reading.


b. X3Dv4 DICOM Profile with OBJ support proposed on medical working group mailing list, discussed in CAD Design Printing Scanning meeting.

Outline of what X3D DICOM Profile for OBJ might look like:

* Motivation is to enable X3D models to be fully interoperable with DICOM requirements, which is choosing WaveFront OBJ format.
* Geometry meshes supported by X3D IndexedFaceSet.  Optionally might add TriangleSet and IndexedTriangleSet.
* Materials support: confirm X3D Material node matches OBJ Material Template Library (MTL).
* Texture images supported by X3D ImageTexture node and desired image formats (e.g. PNG and JPEG).
* Texture transformation supported by X3D TextureCoordinate and TextureTransform nodes.
* Likely not needed (since not mentioned in DICOM requirements) but available if desired: OBJ mathematical surfaces can be Level 2 of X3D DICOM Profile, simply add X3D Extrusion and NURBS.
* Adding ability for X3D to load OBJ files directly is simply using the correspondence between approximately identical capabilities.  We already plan to do this for STL and PLY (simpler than OBJ) as well as glTF (more complex than OBJ).
* Defining these capabilities as an X3D Profile for DICOM matching OBJ encourages full interoperability over long term, simplifying everyone’s use cases and toolchain flows.


* Define MetadataSet structures with DICOM terms of reference to allow direct and completely documented embedding of such a file with corresponding data objects and data elements in a DICOM file.  Presumably these include clinical, visualization and 3D printing requirements.

[1] Wikipedia: Wavefront .obj file

[2] Wikipedia: Wavefront .obj file, Material template library

Since X3D Profiles are geared towards use cases, aiming for a DICOM Profile likely makes best sense.

Vince noted that the proposed OBJ for DICOM profile does not address the issues most important to the medical community using DICOM for clinical 3D printing. They are not seeking workflows that involve translating models between OBJ and X3D formats.

Nevertheless such a profile would allow preparation and archiving of interoperable 3D-printable models (in both directions DICOM <==> X3D) regardless of DICOM policy.

Wondering, if we add HL7 requirements, if we might actually be sketching out the requirements for an advanced X3D Medical Profile?  We currently have

	MedicalInterchange profile

So specific addition of metadata structures and taxonomies, along with annotations for clinical use, might be the missing ingredients for what an X3D profile might need to unlock medical capabilities.  Reportedly:
- HL7 FIHR can embed DICOM data
- Each can specify SNOMED metadata

b. Meanwhile, not to get lost in the forest here:  OBJ mesh/material/texture is between the complexity of STL mesh and glTF geometry/appearance/etc.  So it seems like we should add that to the list of geometry formats expected (currently STL PLY and glTF).

There is reasonable concern that we would be spreading themselves too thin, we need to stay focused.

There are no technical blockers however, so this is an opportunity for someone to contribute the mappings of Shape information (mesh/Material/texture).

We might make the same arguments to take STL off the list of supported capabilities for X3Dv4... defer it to a later version of the specification perhaps.

glTF is clearly a win because it adds new capabilities to X3Dv4 and is critical path.

*Resolution* - we agreed to clearly focus our X3Dv4 efforts: confirmed yes to glTF, but no to STL and OBJ unless someone outside the core implementers takes the time to provide commonly usable converters and specification prose.

Don will update Mantis regarding STL/OBJ and Dick will review on next editors call.


c. Improvements pending on X3D Ontology by X3D Semantic Web working group.  We are now adding queries and have automated testing for that.

More to follow next week.


1. Takamatsu meeting quicklook.

- Humanoid Animation (HAnim) approvals by ISO editors, defenestration of hyphenization for enumeration *HAnim*.
- Medical progress: representing human organs using HAnim, big strategy is possible, HL7 collaboration.
- Smart Cities opportunities abound in future: X3D as connection and presentation layer for many things.
- ISO requested to go open on Mixed Augmented Reality (MAR) specifications.  Bodes well for X3Dv4.1.
- Khronos cooperative dialog and activity continues well.
- Reopened issue: Vince and Don are following up on JTC1 joint group on 3D printing and scanning.

Expect to distribute a number of meeting materials following discussion and review by Web3D Board of Directors.  Membership has value! 8)


2. Standards Relationships diagram - proposed update review, see attached comparison.

Just refinements, no major changes.  Flipping in full-screen mode makes differences easy to compare.

One more week of review comments, expect to approve and publish updated version next week.


3. *glTF X3D Features Comparison*. Would anyone like to lead this review update?

> * Attachment [3]: glTF X3D Features Comparison (3 NOV 2017)
>    https://www.web3d.org/sites/default/files/page/X3D%20Version%204%20Strategy/glTfX3dFeaturesComparison.pdf
> * source at
>    https://docs.google.com/spreadsheets/d/12ebxqfQoFPuNhaz8wZkNE6G-w_bqt98iy6p5F9IazVM/edit#gid=0


4. *X3Dv4 topics*

	X3Dv4 Implementations Status

a. /API Progress Review/ with special thanks to Masaki Aono and Myeong Won Lee.

	Python X3D Package x3d.py

	[x3d-public] testing x3d python jupyter notebook; first-round python viewer

Important collaborations with Myeong Won Lee and Masaki Aono.  Native python X3D viewer published.

Loren Peitso and I continue to fix and refine the x3d.py package, also .toXML() serialization output of .x3d models.

	[x3d-public] ANNOUNCE: X3D SAI Libraries for C, C++, C# (X3DCSAIL, X3DCPPSAIL, X3DCSSAIL)

All three example implementations of these language bindings by Myeong Won Lee and students now in Web3D open-source under Sourceforge version control.


It looks like all of these X3D APIs can/will align together, along with Java implementation (maybe ECMAScript too) through concerted use of

	X3D Unified Object Model (X3DUOM)

Status of Web3D drafts and submissions to ISO:

* We do have NWIPs and prior draft documents at

* Specification timeline spreadsheet

We have sent a query to Dr. Myeong Won Lee to see if she is already working on updating the existing drafts.

This was covered well at meetings of Web3D Korea Chapter last January and at SIGGRAPH last July.  TODO: get those slides online in a good place.

Opportunity: people can review the code and consider improvements.  Members have access, interested parties are welcome to request access.


b. *ISO style guidelines* Our prior work with ISO editors has gotten good attention.  SC24 has endorsed ISO having HTML publication templates.

Dick and Don have this on their TODO list... pretty involved.
- Final touch-up editing and publish HAnim v2 using old style.
- HTML template work will apply to all X3D-related standards and will take time.
- Likely activity will be next spring after X3Dv4 technical submissions are complete.
- X3Dv4 New Work Item Proposal (NWIP) will need to be in new layout.
- There is no specific guidance from ISO, but a few diverse ISO examples exist.
- Meanwhile another resource: the W3C Recommendations layouts are excellent and provide helpful exemplars.

There is an opportunity for anyone who wants to volunteer to help on spec layout in version 4.


c. /Field name changes/ for improved consistency, affects child SF/MFNode field naming for ~10 nodes.

	Potential future changes for improved consistency of field names

These changes are necessary variations on X3Dv4 syntax proposed to avoid unintended mismatches and achieve unified field representations in X3Dv4.

Deferred until next week.


5. *Getting Connected*

Recently Web3D meetings have switched to Zoom channels, to good effect.  Zoom allows use of internet audio, screen sharing, and chat with links.

We meet regularly on Fridays 0800-0930 pacific.  Connection information is available for members on the following page.

	Web3D Members: Teleconference Information

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:
	Join the Web3D Consortium


Group confirmed that no member-only information present.

Steady progress, "steady as she goes..."  Thanks for many many efforts underway, working well in parallel.

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
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