[x3d-public] Removal of Layout component in X3D v4 + DIS summary

Brutzman, Donald (Don) (CIV) brutzman at nps.edu
Tue Oct 8 23:04:24 PDT 2019

Thanks for your note.

On 10/8/2019 12:45 AM, Holger Seelig wrote:
> I don't see why the Layout component should be removed in the new X3D v4 standard. It is fully implemented in X_ITE and Titania, and Titania has a nice Layout Editor, which makes the use of this component very easy. With the Layout component it is possible to place something in a corner or edge of the screen, or make something as large as the screen. Removing this component will removing these possibilities.

Arguments for removing Layout component were based on no apparent implementation or examples being found.  Several people looked around without reporting success, and this was announced several times with no prior comment.

The working group was recently glad to learn during our weekly meeting that you had indeed implemented Layout in X_ITE.  This change affects our next steps:
- identify and share example scenes that demonstrate use, suitable for testing
- encourage other implementations, and
- determine if improvements to the component are needed, either for functional improvement or to further encourage implementation/usage.

For X3Dv4 draft specification, am thinking this also deserves some thinking on how to use Layout component in combination with (or as a separate complement to) HTML.  (ah, looks like Andreas has a post on that this afternoon.)

May I again request that you and other player implementers (or someone out there) review and update our list of supported X3D nodes so that this might be accurate.  It is very helpful in many ways.

	X3D Specifications: Schema and DOCTYPE Validation

	X3D Node Inventory Comparison (.pdf) shows implementation coverage of the X3D Abstract Specification

> I think a better candidate of removing a component is the DIS component. It is a component for purely military use, which I think has nothing to do with X3D standard. The only purpose of this component is to play war like in Counter-Strike, and to model war simulations for the army, which is not my intention.
> Best regards,
> Holger

Hmmm, several statements are at odds there.
- We are not searching for the best candidates among components to remove.
- The usage and purpose you identify are not correct.

Diversity of opinion is welcome but good characterizations are helpful for shared understanding.  Here's a short summary of DIS.

IEEE Distributed Interactive Simulation (DIS) Protocol is a long-established, well-defined and widely implemented standard for multi-participant communications in shared virtual environments.  While it arose several decades ago (early 90s) from the international military modeling and simulation (M+S) community, it also has legitimate uses in other domains.  High fidelity with physics and real-world interactions is a plus.  The component does define distributed virtual environment support for X3D that otherwise requires independent, non-interoperable approaches.  While numerous DVE networking approaches have been proposed and implemented over the years, none have come close to the breadth depth stability or longevity of DIS.

I'm happy to provide a preliminary report that NPS has made much progress in the past year reimplementing DIS.  Previously we had a partial set of DIS Protocol Data Units (PDUs), perhaps a dozen or so, with packet data structures represented in XML and multiple programming-language codebases getting autogenerated.  Now in a new autogenerated version we have all 72 PDUs in Java, along with 20,000 formally defined enumeration values.  As in prior versions of this work, we expect to autogenerate implementation in other programming languages.  We are currently working on release documentation and unit testing (of both software code and data streams) to ensure high quality.  This work is online at github with more information to be released soon.


More about DIS can be found at

	Networked Graphics MV3500 course

	X3D and Distributed Interactive Simulation (DIS)

	Simulation Interoperability Standards Organization (SISO)

	SISO Distributed Interactive Simulation / Real-time Platform Reference Federation Object Model (DIS / RPR FOM) Product Support Group (PSG)

Hope this helps.  Thanks for your many important efforts Holger.

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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