[x3d-public] X3D 4.0 specification problem: ClassicVRML Encoding, clause 5 Encoding of fields
John Carlson
yottzumm at gmail.com
Tue Dec 24 07:36:22 PST 2024
Thanks, Michalis!
I think I found one more, where an MFInt32 is shown as an SFInt32 under
Example 1, without brackets: “value 1”. I believe all MF nodes should have
brackets. Note if brackets are added, the example would be a duplicate.
Question: is an MF field value with just brackets valid?
John
On Tue, Dec 24, 2024 at 3:36 AM Michalis Kamburelis via x3d-public <
x3d-public at web3d.org> wrote:
> Hi,
>
> I looked at
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19776-2v4.0-WD1/Part02/EncodingOfFields.html
> --- looks like a great improvement, thank you! The new prose with new
> examples is indeed more immediately obvious. It's also a good idea to
> use real nodes / fields for the examples, not only artificial fooXxx
> (as before), this makes things even more clear.
>
> One minor thing I noticed: in "5.1.2 Description" there's a typo,
> "around ingle-valued field types". You missed "s" in "single-valued"
> :)
>
> John also has good points (kudos for noticing):
>
> - SFVec2d example in 5.17 is wrong (" inputOutput SFVec2d field20 [
> 0.0 0.0 ]"), it should *not* use [ ].
>
> - SFVec4d in 5.21 is also indeed wrong, "inputOutput SFVec4d field24a
> [ 1.000000000001 42 666.35357878 32.6 ]" -> should have no brackets.
>
> Regards,
> Michalis
>
> wt., 24 gru 2024 o 02:18 Brutzman, Donald (Don) (CIV)
>
> <brutzman at nps.edu> napisał(a):
> >
> > It took several days of effort but this clause is now fixed up. Review
> and comments welcome.
> >
> > Mantis 1484: ClassicVRML Encoding of Fields clause does not include
> proper SFVec examples
> > https://mantis.web3d.org/view.php?id=1484
> >
> > X3D encodings Part 2: Classic VRML encoding, 5 Encoding of fields
> >
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19776-2v4.0-WD1/Part02/EncodingOfFields.html
> >
> > Happy holidays with X3D and VRML! 🙂
> >
> >
> > 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
> https://faculty.nps.edu/brutzman
> >
> >
> >
> >
> > ________________________________
> > From: x3d-public <x3d-public-bounces at web3d.org> on behalf of Brutzman,
> Donald (Don) (CIV) via x3d-public <x3d-public at web3d.org>
> > Sent: Thursday, December 19, 2024 10:43 AM
> > To: Michalis Kamburelis <michalis.kambi at gmail.com>
> > Cc: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>; Extensible 3D
> (X3D) Graphics public discussion <x3d-public at web3d.org>;
> khyoo at chungbuk.ac.kr <khyoo at chungbuk.ac.kr>; Myeong Won Lee <
> myeongwonlee at gmail.com>
> > Subject: Re: [x3d-public] X3D 4.0 specification problem: ClassicVRML
> Encoding, clause 5 Encoding of fields
> >
> > [changed subject line to reflect changed focus]
> >
> > Thanks again for your patient explanations Michalis, totally helpful.
> We have finally zoomed in on the real problem.
> >
> > It is surprising (and maybe a little disappointing) that we have had
> such egregious and misleading omissions in the ClassicVRML field
> descriptions clause, unreported for so many years (since VRML97
> apparently). That was the cause of my mistaken thinking that encoding of
> values were similar. Nevertheless, it is a nice holiday present that we
> have finally identified this source of confusion so that it might finally
> get fixed.
> >
> > X3D 3.3 ClassicVRML Encoding, clause 5 Encoding of fields
> >
> https://www.web3d.org/documents/specifications/19776-2/V3.3/Part02/EncodingOfFields.html
> >
> > Have checked X3dToClassicVRML.xslt and X3dToVRML97.xslt stylesheet
> converters, X3DJSAIL export, and our many many X3D Example Archives
> scenes. They match what you are saying (thank goodness).
> >
> > I am adding this problem to the issue tracker. Dick and I will work on
> a revision for community review.
> >
> > Mantis 1484: ClassicVRML field reference does not include proper SFVec
> examples
> > https://mantis.web3d.org/view.php?id=1484
> >
> > Future revisions will appear in github and as follows. Let's watch for
> similar unintended errors in the specification, the ripples from spec
> errors spread a wide wake.
> >
> > X3D 4.0 ClassicVRML Encoding, clause 5 Encoding of fields
> >
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19776-2v4.0-WD1/Part02/EncodingOfFields.html
> >
> > Of course I also agree that fast efficient rigorous parsing holds
> essential importance. Your castle-model-viewer and castle-model-converter
> continue to be essential in our sustained efforts to get ClassicVRML
> exactly right.
> >
> > Castle Model Converter (formerly tovrmlx3d))
> > https://castle-engine.io/castle-model-converter
> >
> > Looking forward to continuing relentless progress with ClassicVRML and
> X3D! 🙂
> >
> >
> > 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
> https://faculty.nps.edu/brutzman
> >
> >
> >
> >
> > ________________________________
> > From: Michalis Kamburelis <michalis.kambi at gmail.com>
> > Sent: Wednesday, December 18, 2024 8:38 PM
> > To: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
> > Cc: Extensible 3D (X3D) Graphics public discussion <x3d-public at web3d.org>;
> khyoo at chungbuk.ac.kr <khyoo at chungbuk.ac.kr>; Myeong Won Lee <
> myeongwonlee at gmail.com>
> > Subject: Re: [x3d-public] X3D 4.0 specification problem:
> TextureProjectorparallel.fieldOfView
> >
> > NPS WARNING: *external sender* verify before acting.
> >
> >
> > Hi Don,
> >
> > AD A -
> >
> > No, when writing the SFVec4f in X3D classic encoding, the square
> > brackets "[ ... ]" cannot be used. I believe my understanding matches
> > both the spec and all existing X3D implementations.
> >
> > 1. The example you noticed (on
> >
> https://www.web3d.org/documents/specifications/19776-2/V3.3/Part02/EncodingOfFields.html#SFVec4f
> > ) ... shows MFVec4f, not SFVec4f .
> >
> > It's indeed a bit misleading, as the spec section titled "5.20
> > SFVec3f and MFVec3f" describes both MF- and SF- variants. And the
> > example "fooVec3d [ 1.000000000001 42 666.35357878 32.6, 7 94
> > 0.100000000007 143.998 ]" lacks any annotation. Adding there a
> > description would help: "This is an example of MFVec4f in classic
> > encoding, fooVec3d contains here two 4-dimensional vectors." .
> >
> > 2. On the same page, the text higher makes it clear that "square
> > brackets" are used for multiple-value fields: """Multiple-valued
> > fields are written as an ordered list of values enclosed in square
> > brackets and separated by whitespace."""
> >
> > 3. The grammar on
> >
> https://www.web3d.org/documents/specifications/19776-2/V3.3/Part02/grammar.html
> > confirms it:
> >
> > """
> > mffloatValue ::=
> > sffloatValue |
> > [ ] |
> > [ sffloatValues ] ;
> >
> > ....
> >
> > sfvec4fValue ::=float float float float ;
> > """"
> >
> > No square brackets for sfvec4fValue . (And that's good I think; square
> > brackets are consistently used in X3D classic encoding for lists of
> > values.)
> >
> > I do find the grammar very helpful to resolve such questions :) It's
> > unambiguous, and implementations (using my own) follow it literally.
> >
> > So, I think my concern still stands. Changing
> > OrthoViewport.fieldOfView type (MFFloat -> SFVec4f) would break
> > parsing of all the models in X3D classic encoding (and VRML 2.0) that
> > specify value of this field. They use right now square brackets [ .. ]
> > (necessary for MFFloat with > 1 value), which are not allowed for
> > SFVec4f.
> >
> > I honestly don't think there's a way to avoid it, except reverting
> > this spec change. I cannot change in our implementation
> > OrthoViewport.fieldOfView to SFVec4f -- I have users using classic
> > encoding, and VRML 2.0 too, we cannot really break it. And maintaining
> > exceptional treatment in the parser (to allow both MFFloat and
> > SFVec4f) is not maintainable, we cannot have special rules like this
> > (that depend on node and field name) at the parser level.
> >
> > I know that we could change the grammar (to allow [ ... ] in SFVec4f)
> > but IMHO we should not change the grammar (which will complicate
> > parsing) just to account this one single exceptional change to one
> > field in one node.
> >
> > AD B - No, I didn't describe any special handling in our parser. And
> > such exceptions during parsing would be really hard to maintain, I
> > deliberately don't want them. Parser should not have any special rules
> > for specific nodes or fields -- this makes parser code more obvious.
> >
> > On the contrary -- we parse OrthoViewport.fieldOfView as MFFloat
> > now. Only later (after parsing) we just look at the count of MFFloat.
> > When it's less than 4, we treat the remaining numbers as if they were
> > default. But this is nice "local" code near OrthoViewport.fieldOfView
> > logic. It's *not* part of the parser.
> >
> > Regards,
> > Michalis
> >
> > czw., 19 gru 2024 o 03:06 Brutzman, Donald (Don) (CIV)
> > <brutzman at nps.edu> napisał(a):
> > >
> > > Thanks for looking at this Michalis.
> > >
> > > A. Sorry but I'm not clear about what you are saying... Went to look
> at the existing ClassicVRML encoding and it is showing [square brackets]
> for SFVec4f:
> > >
> > > X3D Classic VRML encoding, clause 5 encoding of fields, 5.22 SFVec4f
> and MFVec4f
> > >
> https://www.web3d.org/documents/specifications/19776-2/V3.3/Part02/EncodingOfFields.html#SFVec4f
> > >
> > > The SFVec4f field specifies a four-dimensional (4D) single-precision
> vector. An MFVec4f field specifies zero or more 4D single-precision
> vectors. SFVec4f's and MFVec4f's are encoded as four ISO C floating point
> values (see ISO/IEC 9899) separated by whitespace.
> > > EXAMPLE
> > > fooVec3f [ 1 42 666 -43.8, 7 94 0 0.0001 ]
> > >
> > > ... And so am expecting your SFVec4f example would look the same,
> with [square brackets] around numeric values. Please advise what you
> think.
> > >
> > > OrthoViewpoint { fieldOfView [ -1 -1 1 1 ] }
> > >
> > >
> > > B. Depending on that, am next wondering... you describe how the
> current MFFloat approach already requires additional special handling by
> your parser if an incorrect number of values is encountered. If there is a
> difference regarding [square brackets] for SFVec4f then maybe a parser
> adjustment for that might be possible too... Or, even if they are the same,
> maybe just keeping your error-handling parser for v3.3 content the same
> (also for backwards reliability) is a good idea also.
> > >
> > > C. We are currently working on ClassicVRML Encoding spec for v4.0 now,
> so if any problems are found then we can resolve them.
> > >
> > > D. I found several problems with the Grammar... Dick and I also
> discussed them yesterday. When time permits, will post about that soon.
> > >
> > > Have fun with X3D ClassicVRML Encoding! 🙂
> > >
> > >
> > > 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
> https://faculty.nps.edu/brutzman
> > >
> > >
> > >
> > >
> > > ________________________________
> > > From: x3d-public <x3d-public-bounces at web3d.org> on behalf of Michalis
> Kamburelis via x3d-public <x3d-public at web3d.org>
> > > Sent: Wednesday, December 18, 2024 5:37 PM
> > > To: Extensible 3D (X3D) Graphics public discussion <
> x3d-public at web3d.org>
> > > Cc: Michalis Kamburelis <michalis.kambi at gmail.com>;
> khyoo at chungbuk.ac.kr <khyoo at chungbuk.ac.kr>; Myeong Won Lee <
> myeongwonlee at gmail.com>
> > > Subject: Re: [x3d-public] X3D 4.0 specification problem:
> TextureProjectorparallel.fieldOfView
> > >
> > > The change of OrthoViewpoint.fieldOfView from MFFloat to SFVec4f
> > > breaks compatibility (badly) for X3D classic encoding, from what I can
> > > see.
> > >
> > > Previously (when OrthoViewpoint.fieldOfView is MFFloat, so in X3D <=
> > > 4.0 and VRML 2.0) this was valid:
> > >
> > > OrthoViewpoint { fieldOfView [ -1 -1 1 1 ] }
> > >
> > > And this was "undefined how it works (spec doesn't say what happens
> > > for < 4 values), but at least parsing was OK" (CGE made some effort to
> > > tolerate it):
> > >
> > > OrthoViewpoint { fieldOfView [ -1 -1 ] }
> > >
> > > Now (when OrthoViewpoint.fieldOfView is SFVec4f) both above are
> > > invalid, at parsing. One has to write this:
> > >
> > > OrthoViewpoint { fieldOfView -1 -1 1 1 }
> > >
> > > ... but the new form is invalid if loaded into a browser that expects
> > > OrthoViewpoint.fieldOfView to be old MFFloat.
> > >
> > > And, before anyone suggests this: It's not reasonable for X3D browsers
> > > to define OrthoViewpoint.fieldOfView with one type for X3D >= 4.1, and
> > > another type for older X3D versions. At least I cannot imagine
> > > maintaining this exceptional behavior throughout the codebase :) We
> > > need to have a one definition of OrthoViewpoint with one type for
> > > fieldOfView, otherwise we cause a big complication (also for
> > > developers using our API).
> > >
> > > So, I'm a bit baffled what to do. If I change
> > > OrthoViewpoint.fieldOfView to SFVec4f, I *will* break some X3D models
> > > for users and I will get bugreports about it. If I don't, I will not
> > > be compatible with X3D 4.1. For now, I choose the latter.
> > >
> > > Regards,
> > > Michalis
> > >
> > > czw., 19 gru 2024 o 01:42 John Carlson via x3d-public
> > > <x3d-public at web3d.org> napisał(a):
> > >
> > >
> > >
> > > >
> > > > I’m imagining there will be changes to C++ SAI. Once new types are
> in place I can attempt to test. I suggest getting an X3DUOM out soon, so I
> can regenerate my fieldTypes.js file, which affects all my serializers.
> > > >
> > > > No one is using my serializers that I know of, so this particular
> change won’t probably affect anyone. They would have to update, and I
> don’t currently recommend that.
> > > >
> > > > Bug reports are welcome:
> > > >
> > > >
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fcoderextreme%2FX3DJSONLD%2Fissues&data=05%7C02%7Cbrutzman%40nps.edu%7C98ebb53e439741334cb708dd1fe70c37%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C638701800556379299%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C80000%7C%7C%7C&sdata=sNGbCXeuSBEnFH2Mnp8RVNttmB%2FqDIKHhbv6YaxdOjE%3D&reserved=0
> > > >
> > > >
> > > > AFAIK, this does not affect X3D JSON, since MFFloat and SFVec4f are
> represented by arrays.
> > > >
> > > > If you recommend tweaking X3DUOM before your release, I can see what
> I can do, but it’s not currently a priority for me. Reading the X_ITE
> component into Blender is higher priority.
> > > >
> > > > Someone speaking up can change the priority.
> > > >
> > > > John
> > > >
> > > > On Wed, Dec 18, 2024 at 6:00 PM Brutzman, Donald (Don) (CIV) via
> x3d-public <x3d-public at web3d.org> wrote:
> > > >>
> > > >> During a specification editors' meeting yesterday, Dick and I made
> another step forward.
> > > >>
> > > >> Mantis 1398: OrthoViewpoint fieldOfView type needs to be SFVec4f,
> not MFFloat
> > > >> https://mantis.web3d.org/view.php?id=1398
> > > >>
> > > >> namely
> > > >>
> > > >> If specialty methods for homogeneous transformations (or other
> operations) are needed by SAI implementations, they can receive specialized
> definitions to match.
> > > >> It is important to remember that (a) no nodes currently use
> homogenous coordinates, and (b) ClipPlane definition of a half-plane is
> different than the two parallel-projection extents.
> > > >> A graceful approach not requiring implementation changes might be
> adding prose to Clause 5 field definitions noting alternate usages may
> occur. For example, appended to the fist sentence, "or other usage of a
> 4-tuple."
> > > >>
> > > >> We applied that change in draft X3D 4.1 Architecture, also
> committed into git and pushed online.
> > > >>
> > > >> 5.3.20 SFVec4d and MFVec4d
> > > >>
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/fieldTypes.html#SFVec4dAndMFVec4d
> > > >> 5.3.21 SFVec4f and MFVec4f
> > > >>
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/fieldTypes.html#SFVec4fAndMFVec4f
> > > >>
> > > >> ==========================
> > > >> 5.3.20 SFVec4d and MFVec4d
> > > >> The SFVec4d field or event specifies a three-dimensional (3D)
> homogeneous vector, or other usage of a 4-tuple. An MFVec4d field or event
> specifies zero or more SFVec4d values. 3D homogeneous vectors. SFVec4d's
> and MFVec4d's are represented as a 4-tuple of double-precision floating
> point values (see 5.3.4 SFDouble and MFDouble). The allowable form for a
> double-precision floating point number is defined in the specific encoding.
> > > >> The default value of an uninitialized SFVec4d field is (0 0 0 1).
> The default value of an MFVec4d field is the empty list.
> > > >> 5.3.21 SFVec4f and MFVec4f
> > > >> The SFVec4f field or event specifies a three-dimensional (3D)
> homogeneous vector, or other usage of a 4-tuple. An MFVec4f field or event
> specifies zero or more SFVec4f values. 3D homogeneous vectors. SFVec4f's
> and MFVec4f's are represented as a 4-tuple of single-precision floating
> point values (see 5.3.5 SFFloat and MFFloat). The allowable form for a
> single-precision floating point number is defined in the specific encoding.
> > > >> The default value of an uninitialized SFVec4f field is (0 0 0 1).
> The default value of an MFVec4f field is the empty list.
> > > >> ==========================
> > > >>
> > > >> If anyone can think of any reason not to restrict validation of
> OrthoViewpoint fieldOfView to SFVec4f, instead of an MFFloat array of
> length 4, please speak up. Am hoping to apply this change next to
> validation tools next, improving quality assurance and author confidence
> that a model is valid. Avoiding run-time errors and maintaining
> consistency, with no harm to existing X3D models or implementations, is
> important.
> > > >>
> > > >> Have fun with high-quality X3D! 🙂
> > > >>
> > > >>
> > > >> 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
> https://faculty.nps.edu/brutzman
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> ________________________________
> > > >> From: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
> > > >> Sent: Friday, December 13, 2024 1:14 PM
> > > >> To: Holger Seelig <holger.seelig at yahoo.de>; X3D <
> x3d-public at web3d.org>
> > > >> Cc: khyoo at chungbuk.ac.kr <khyoo at chungbuk.ac.kr>; Myeong Won Lee <
> myeongwonlee at gmail.com>
> > > >> Subject: Re: [x3d-public] X3D 4.0 specification problem:
> TextureProjectorparallel.fieldOfView
> > > >>
> > > >> Excellent question, thanks for asking Holger.
> > > >>
> > > >> This issue has been carefully tracked and regularly revisited since
> July 2022.
> > > >>
> > > >> Mantis 1398: OrthoViewpoint fieldOfView type needs to be SFVec4f,
> not MFFloat
> > > >> https://mantis.web3d.org/view.php?id=1398
> > > >> Mantis 1468: must SFVec4f/SFVec4d fields be homogeneous?
> > > >> https://mantis.web3d.org/view.php?id=1468
> > > >>
> > > >> The X3D Working Group was unable to reach consensus on this issue
> prior to conclusion of version 4.0, unfortunately. Dick Puk and I took a
> close look at this recently too. Here is a synopsis of the Mantis issues.
> > > >>
> > > >> I advocate use of SFVec4f for all parallel fieldOfView values
> because it is the strictest appropriate datatype that can validate content.
> Retaining the legacy MFFloat type definition for fieldOfView allows 3d
> models (produced by humans or tools) to define arrays of illegal length,
> making failures mysterious. Conceptual consistency is important too.
> > > >>
> > > >> Reviewing the Mantis issues, additional concerns included:
> > > >>
> > > >> Incompatibility with prior X3D implementations. Since a 4-tuple
> content value is a valid MFFloat array, I'm not seeing any backwards
> incompatibility if a prior X3D 3.3 implementation encounters the four
> values of a SFVec4f array. There are no representation problems since
> value syntax is compatible for our various encodings as well.
> > > >>
> > > >> SFVec4f fields are actually not homogenous coordinates. The spec
> uses the word "homogenous" when referring to
> > > >>
> > > >> X3D4 Architecture, Clause 5 Field type reference, 5.3.20 SFVec4d
> and MFVec4d
> > > >>
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/fieldTypes.html#SFVec4dAndMFVec4d
> > > >> "The SFVec4f field or event specifies a three-dimensional (3D)
> homogeneous vector." (and similarly for SFVec4d, SFVec4f and MFVec4f).
> > > >> However none of these fields are mathematically homogeneous, see
> > > >>
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHomogeneous_coordinates&data=05%7C02%7Cbrutzman%40nps.edu%7C98ebb53e439741334cb708dd1fe70c37%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C638701800556398488%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C80000%7C%7C%7C&sdata=%2F3CZD9IDEdkAZaIJ9BWi4dKFk0mblQfkBstpx0lEsg0%3D&reserved=0
> > > >>
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FHomogeneous_coordinates%23%2Fmedia%2FFile%3ARationalBezier2D.svg&data=05%7C02%7Cbrutzman%40nps.edu%7C98ebb53e439741334cb708dd1fe70c37%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C638701800556410503%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C80000%7C%7C%7C&sdata=Q%2BWMcMy2W%2FYzedb2wd7Efsgd28M1of%2FFy3pO2GKRTF4%3D&reserved=0
> > > >> Of related note is that ClipPlane 4-tuple "plane" field is also
> SFVec4f.
> > > >>
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/rendering.html#ClipPlane
> > > >>
> > > >> All review welcome, hopefully I have correctly synopsized all
> concerns.
> > > >>
> > > >> I think it would be beneficial to resolve this issue by reaching
> consensus and applying remedies as follow.
> > > >>
> > > >> Omitting the over-strict word "homogenous" from the four SF/MF Vec
> 4f/4d definitions in future X3D 4.1 prose,
> > > >> Updating future X3D 4.1 prose to use SFVec4f for
> TextureProjectorParallel fieldOfView,
> > > >> Using SFVec4f in X3D 4.0 DTD, Schema, X3DUOM validation and X3D
> Tooltips, since that type strictly confirms fieldOfView correctness with no
> backwards compatibility problems.
> > > >>
> > > >> Is consensus now possible? Thanks for all careful consideration.
> > > >>
> > > >> 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
> https://faculty.nps.edu/brutzman
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> ________________________________
> > > >> From: Holger Seelig <holger.seelig at yahoo.de>
> > > >> Sent: Friday, December 13, 2024 11:29 AM
> > > >> To: X3D <x3d-public at web3d.org>
> > > >> Cc: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>;
> khyoo at chungbuk.ac.kr <khyoo at chungbuk.ac.kr>; Myeong Won Lee <
> myeongwonlee at gmail.com>
> > > >> Subject: Re: [x3d-public] X3D 4.0 specification problem: upVector
> field for TextureProjector, TextureProjectorParallel
> > > >>
> > > >> I just realised that TextureProjectorparallel.fieldOfView is of
> type SFVec4f, but OrthoViewpoint.fieldOfView is of type MFFloat.
> > > >>
> > > >> Which of the two is better?
> > > >>
> > > >> OrthoViewpoint is definitely older.
> > > >>
> > > >> I think of SFVec4f as a mathematical 4d vector.
> > > >>
> > > >>
> https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/components/textureProjection.html#TextureProjectorParallel
> > > >>
> https://www.web3d.org/documents/specifications/19775-1/V4.0/Part01/components/navigation.html#OrthoViewpoint
> > > >>
> > > >> Best regards,
> > > >> Holger
> > > >>
> > > >> --
> > > >> Holger Seelig
> > > >> Leipzig, Germany
> > > >>
> > > >> holger.seelig at yahoo.de
> > > >>
> https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcreate3000.github.io%2Fx_ite%2F&data=05%7C02%7Cbrutzman%40nps.edu%7C98ebb53e439741334cb708dd1fe70c37%7C6d936231a51740ea9199f7578963378e%7C0%7C0%7C638701800556422280%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C80000%7C%7C%7C&sdata=EyAy636i6iNSYFBrRDdqg178Wi93D3sVzQJQ%2FqGIxDc%3D&reserved=0
> > > >>
> > > >> Am 08.12.2024 um 05:21 schrieb Brutzman, Donald (Don) (CIV) via
> x3d-public <x3d-public at web3d.org>:
> > > >>
> > > >> However
> > > >>
> > > >>
> > > >> _______________________________________________
> > > >> x3d-public mailing list
> > > >> x3d-public at web3d.org
> > > >> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> > > >
> > > > _______________________________________________
> > > > x3d-public mailing list
> > > > x3d-public at web3d.org
> > > > http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> > >
> > > _______________________________________________
> > > x3d-public mailing list
> > > x3d-public at web3d.org
> > > http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>
> _______________________________________________
> x3d-public mailing list
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> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>
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