[x3d-public] Simplifying ProtoInstance nodes

Sun May 11 20:42:59 PDT 2025

To begin to address validation of short syntax instances, it may be
possible, as John also noted, to first transform, perhaps with xslt, each
such node in a x3d document to long, traditional syntax and then validate
that result.

Since automatically generated long ProtoInstance syntax should always be
valid x3d, the value would come from detecting problems during the
transformation process, and from making it possible to validate the
complete document.

One drawback is that mistyped native nodes would be interpreted as proto
instances and may escape invalidation. This is somewhat similar to long
form mistyped Proto instance names also escaping invalidation as long as
there is no full parsing of proto declarations.

To work around this, documents which wish to be more strictly validated
could be required to tag short syntax instances by a metadata convention,
by an additional XML attribute or by a naming convention:

<ProtoTable proto='true' ... />

This way validation could distinguish between nodes with intentional and
unintentional names.

Andreas

On Sat, May 10, 2025, 5:26 PM Andreas Plesch <andreasplesch at gmail.com>
wrote:

> I actually think I have never tested when a Proto has the same name as a
> native node in x3dom.
>
> Here is an example for 'Box':
>
>
> https://andreasplesch.github.io/Library/Viewer/index.html?url=https://gist.githubusercontent.com/andreasplesch/5e2c6068d0495605198f9a20254c7519/raw/91ee41a9afbb8ee9dec5952108bf13bdc41f4de0/ProtoBoxCollision.x3d
>
> It appears that the Proto redefinition takes precedence.
>
> Here is an example for 'Group':
>
>
> https://andreasplesch.github.io/Library/Viewer/index.html?url=https://gist.githubusercontent.com/andreasplesch/5e2c6068d0495605198f9a20254c7519/raw/3b7a53131c0c890b9672b38ae083c81c8524d60e/ProtoNativeCollisionTest.x3d
>
> This is more complicated but I think the Proto definition still takes
> precedence except that now only the first child of the type transform is
> rendered.
>
> I would suggest letting browser behaviour for that case remain undefined
> to discourage authors to somehow cleverly apply such a feature.
>
> Andreas Plesch
> Waltham, MA 02453
>
> On Sat, May 10, 2025, 3:39 PM <x3d-public-request at web3d.org> wrote:
>
>> Date: Sat, 10 May 2025 21:37:47 +0200
>> From: Holger Seelig <holger.seelig at yahoo.de>
>> To: X3D <x3d-public at web3d.org>
>> Subject: Re: [x3d-public] Simplifying ProtoInstance nodes
>> Message-ID: <67EB2216-BC2C-4A50-9E57-122241628399 at yahoo.de>
>> Content-Type: text/plain; charset="utf-8"
>>
>> There is another drawback which already exist in VRML encoding. What take
>> precedence if a PROTO is named as a build-in node. Consider a PROTO named
>> Box with a Sphere as root node. What is happening if a Box is now
>> instantiated?
>>
>> PROTO Box []
>> {
>>   Sphere {}
>> }
>>
>> Shape {
>>   Box {}
>> }
>>
>> This behaviour is not handled by the specification, but X_ITE does the
>> following: build-in nodes will take precedence over over PROTO nodes, it
>> will still display a Box node. Don?t know what Caste or X3DOM does. With
>> current XML encoding this is very cleared and there is no prob at all. But
>> in VRML encoding or with XML ?short syntax? this may be worth a spec
>> comment.
>>
>> Best regards,
>> Holger
>>
>> --
>> Holger Seelig
>> Leipzig, Germany
>>
>> holger.seelig at yahoo.de
>> https://create3000.github.io/x_ite/
>> https://patreon.com/X_ITE
>>
>>
>>
>> > Am 10.05.2025 um 20:44 schrieb Brutzman, Donald (Don) (CIV) via
>> x3d-public <x3d-public at web3d.org>:
>> >
>> > +1 on all counts, thanks for thoughtful consideration Michalis.
>> >
>> > Further considerations are always welcome.
>> >
>> > Next week Dick and I will review comments, then consider a Mantis issue
>> and draft prose addition to X3D XML Encoding.
>> >
>> > 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
>> >
>> >
>> > From: Michalis Kamburelis
>> > Sent: Saturday, May 10, 2025 11:38 AM
>> > To: Extensible 3D (X3D) Graphics public discussion
>> > Cc: Brutzman, Donald (Don) (CIV)
>> > Subject: Re: [x3d-public] Simplifying ProtoInstance nodes
>> >
>> > I think this short form (in XML encoding) makes sense, and Castle Game
>> Engine / Castle Model Viewer could support it too.
>> >
>> > It makes XML encoding and classic encoding more consistent: you can use
>> PROTO to define a new node, and then use the new node with the same syntax
>> as "built-in nodes". This is already true for classic encoding, it's nice
>> to bring this feature to XML encoding.
>> >
>> > Don has already expressed the important drawback of this "short form":
>> such XML will not validate. I mean, it will validate in X3D-specific tools
>> like "castle-model-converter --validate .." (once we add support for it),
>> but the general XML validation using XML Schema has no way of validating
>> it. You cannot tell in XML schema "this XML element name is valid, if
>> defined by some XML attribute elsewhere". I'm guessing this was the whole
>> reason why ProtoInstance, fieldValue etc. were invented in XML encoding.
>> >
>> > I'm guessing in JSON X3D encoding, the consideration will be similar:
>> it can be implemented, but the resulting file will not validate with JSON
>> schema ( https://json-schema.org/ ).
>> >
>> > Anyhow, if we're all fine with accepting this drawback, then we sure
>> can go ahead and add it to spec :) As long as "long form" remains
>> available, and thus tools like XML schema and JSON schema remain useful, I
>> think it makes sense to have this choice.
>> >
>> > Regards,
>> > Michalis
>> >
>> > sob., 10 maj 2025 o 18:38 Brutzman, Donald (Don) (CIV) via x3d-public <
>> x3d-public at web3d.org <mailto:x3d-public at web3d.org>> napisa?(a):
>> > Thanks for the interesting, innovative discussion.  Excerpting the
>> example:
>> >
>> >
>> https://create3000.github.io/x_ite/tutorials/creating-new-node-types/#using-prototyped-nodes
>> >
>> > _________________________
>> > XML Encoding
>> > 1
>> > 2
>> > 3
>> > 4
>> > 5
>> > 6
>> > 7
>> > 8
>> > 9
>> > <!-- Official Syntax -->
>> > <ProtoInstance name='BouncingBall'>
>> >   <fieldValue name='cycleInterval' value='2'/>
>> >   <fieldValue name='bounceHeight' value='3'/>
>> > </ProtoInstance>
>> > <!-- Short Syntax -->
>> > <BouncingBall
>> >     cycleInterval='2'
>> >     bounceHeight='3'/>
>> > Classic VRML Encoding
>> > 1
>> > 2
>> > 3
>> > 4
>> > BouncingBall {
>> >   cycleInterval 2.0
>> >   bounceHeight  3.0
>> > }
>> > _________________________
>> >
>> > One drawback with the "short" XML syntax is that it will not pass XML
>> DOCTYPE or XML Schema validation, although it still must conform to XML
>> well-formed rules.  Additional tool-specific capabilities can check for
>> such correctness during parsing, of course.  Avoiding XML validation
>> relaxes quality assurance (QA)  for the entire scene, not just that
>> prototype instance, and so use of the short form should be considered
>> carefully.
>> >
>> > Of course there is much merit too, not least of which are readability
>> and consistency with other XML-encoded nodes.
>> >
>> > As it turns out, now is a good time to consider such a change to the
>> X3D Standards suite.  We have highly mature documents defining X3D
>> encodings using XML and ClassicVRML syntax.  Conceivably a "short" form for
>> ProtoInstance will carry over satisfactorily for JSON and other encodings
>> as well, when we get to them this fall.
>> >
>> > If X_ITE and X3DOM already handle this form, and if Castle Model Viewer
>> (Castle Game Engine) is also supportive, I'm not yet seeing any blockers to
>> adoption.  Further implementation and evaluation of course will be useful
>> >
>> > Reference and specific clause that would need modification:
>> >
>> > X3D XML Encoding 4.0 <
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19776-1v4.0-WD1/Part01/X3D_XML.html>
>> revision 19776-1
>> > 4.3.3.2  ProtoInstance node and fieldValue statement syntax
>> >
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19776-1v4.0-WD1/Part01/concepts.html#ProtoInstanceAndFieldValueStatement
>> >
>> > Probably no changes needed:
>> >
>> > X3D Classic VRML Encoding 4.0 <
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19776-2v4.0-WD1/Part02/X3D_ClassicVRML.html>
>> revision 19776-2
>> > 4.3.3.2 Prototype instances and field value initialization syntax
>> >
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19776-2v4.0-WD1/Part02/concepts.html#ProtoInstanceAndFieldValueStatement
>> >
>> > X3D Architecture 4.1 <
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/Architecture.html>,
>> revision 19775-1
>> > 4.4.4 Prototype semantics
>> >
>> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/concepts.html#PrototypeSemantics
>> >
>> > Thanks for careful consideration of this potential capability.  All
>> feedback welcome.
>> >
>> > Have fun with X3D extensibility!  ?
>> >
>> > 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
>> >
>> >
>> > From: x3d-public on behalf of Holger Seelig via x3d-public
>> > Sent: Saturday, May 10, 2025 1:13 AM
>> > To: X3D
>> > Cc: Holger Seelig
>> > Subject: Re: [x3d-public] Simplifying ProtoInstance nodes
>> >
>> > This is already possible if you use the ?short syntax? of a proto
>> instance:
>> >
>> >
>> https://create3000.github.io/x_ite/tutorials/creating-new-node-types/#using-prototyped-nodes
>> >
>> > You can use this in X_ITE, but also in X3DOM.
>> >
>> > Best regards,
>> > Holger
>> >
>> > --
>> > Holger Seelig
>> > Leipzig, Germany
>> >
>> > holger.seelig at yahoo.de <mailto:holger.seelig at yahoo.de>
>> > https://create3000.github.io/x_ite/
>> > https://patreon.com/X_ITE
>> >
>> >
>> >
>> > Am 10.05.2025 um 05:55 schrieb John Carlson via x3d-public <
>> x3d-public at web3d.org <mailto:x3d-public at web3d.org>>:
>> >
>> > My thought is to replace ?ProtoInstance? tags with ?MenuItem? tags, and
>> fieldValue statements with attributes, but I?ve not done that before. My
>> goal is to make the model more accessible to screen readers.
>> >
>> > Any examples are welcome.
>> >
>> > See attached link and model.
>> >
>> > John
>> >
>> > ---------- Forwarded message ---------
>> > From: John Carlson <yottzumm at gmail.com <mailto:yottzumm at gmail.com>>
>> > Date: Thu, Mar 6, 2025 at 4:35?PM
>> > Subject: Latest cleaned Jin FACS (needs metadata)
>> > To: Don Brutzman <brutzman at nps.edu <mailto:brutzman at nps.edu>>, Joe D
>> Williams <joedwil at earthlink.net <mailto:joedwil at earthlink.net>>
>> >
>> >
>> > Attached.
>> >
>> > And:
>> >
>> https://create3000.github.io/x_ite/playground/?url=https://raw.githubusercontent.com/coderextreme/ci2had/refs/heads/main/resources/CleanedYouClocks.x3d
>> >
>> > John
>> > <CleanedYouClocks.x3d>_______________________________________________
>> > x3d-public mailing list
>> > x3d-public at web3d.org <mailto:x3d-public at web3d.org>
>> > http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>> >
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