[x3d-public] visibilityRange for X3DFogObject: specification erratum detected, corrections applied IAW Web3D Consortium policy/practice

Thu Nov 2 07:59:25 PDT 2023

Thanks for all insights and inputs.  Dick and I have applied these errata
changes, checked them into Web3D Consortium member-only github archive, and
closed the three corresponding Mantis issues.  Following review of the final
.zip versions, they will be submitted to ISO for final consideration and
review.

Checking of these modifications is appreciated.  Note also that the first
part of the document title has been changed in accordance with ISO JTC1 SC24
guidance.

*	X3D 4.0 Architecture
*	"The full title of this document is: Information technology for
computer graphics, image processing and environmental data representation -
Extensible 3D (X3D) - Part 1: Architecture and base components."
*
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.proof/Pa
rt01/components/ Architecture.html

*	X3D 4.0 Architecture, clause 1 Scope
*
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.proof/Pa
rt01/ scope.html

*	X3D 4.0 Architecture, 24 Environmental effects component, 24.3.2
X3DFogObject
*
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.proof/Pa
rt01/components/environmentalEffects.html#X3DFogObject

*	X3D 4.0 Architecture, 24 Environmental effects component, 24.4.4
LocalFog
*
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.proof/Pa
rt01/components/environmentalEffects.html# LocalFog

Web3D Consortium membership has value.  Everyone is encouraged to join, we
all have great influence and impact working together.

*	Web3D Consortium: Join
*	https://www.web3d.org/join

Have fun with X3D 4.0!   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 https://faculty.nps.edu/brutzman

From: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu> 
Sent: Sunday, October 29, 2023 9:35 PM
To: Michalis Kamburelis <michalis.kambi at gmail.com>; Andreas Plesch
<andreasplesch at gmail.com>; Holger Seelig <holger.seelig at yahoo.de>;
puk at igraphics.com
Cc: X3D <x3d-public at web3d.org>; Brutzman, Donald (Don) (CIV)
<brutzman at nps.edu>
Subject: RE: [x3d-public] visibilityRange for X3DFogObject: specification
erratum detected

I have entered these excellent comments in the Mantis issue tracker as

*	Mantis 1444: Table 17.5 missing description of local variable
fogVisibility; table term/title errata
*	https://www.web3d.org/member-only/mantis/view.php?id=1444

*	Mantis 1445: 24.3.2 X3DFogObject, 24.4.4 LocalFog have incorrect
negative signum on limit for visibilityRange
*	https://www.web3d.org/member-only/mantis/view.php?id=1445

Dick and I are meeting with other ISO editors Monday.  The changes are
editorial, and so am hoping that these corrections can be applied now as
formal editor comments pending final ISO/IEC approval of the ISO proof
document.  If not, they will have to be a formal corrigendum or else
postponed to X3D 4.1.

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

-----Original Message-----
From: Michalis Kamburelis <michalis.kambi at gmail.com
<mailto:michalis.kambi at gmail.com> > 
Sent: Wednesday, October 18, 2023 12:29 PM
To: Andreas Plesch <andreasplesch at gmail.com <mailto:andreasplesch at gmail.com>
>
Cc: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu <mailto:brutzman at nps.edu>
>; Holger Seelig <holger.seelig at yahoo.de <mailto:holger.seelig at yahoo.de> >;
puk at igraphics.com <mailto:puk at igraphics.com> ; X3D <x3d-public at web3d.org
<mailto:x3d-public at web3d.org> >
Subject: Re: [x3d-public] visibilityRange for X3DFogObject: specification
erratum detected

NPS WARNING: *external sender* verify before acting.

Hi,

I completely agree with Andreas proposed addition to define

"""

- fogVisibility (Table 17.5) is the currently bound fog's visibilityRange,
in the same coordinate system as fogDistance.

"""

> Michalis may have background on introducing the 'fogVisibility' term.

> Perhaps it is an attempt to decouple from the fog node to allow 

> flexible use of world or local coordinate systems for computations.

I'm afraid I don't have any additional insight as to why it is called
"fogVisibility". It was already called like that in X3D 3.3, before my PBR
edits (
<https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/componen
ts/lighting.html>
https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/component
s/lighting.html

) and it was also not explicitly defined there. So I neither broke nor
improved that state when editing that section for X3D 4.0 :) The theory
above from Andreas sounds good -- i.e. the term is called "fogVisibility" to
make it clear that it is not "just straightforward visibilityRange" value,
and instead it is "visibilityRange converted

(scaled) by the fog node transformation".

I believe the intention was always just like Andreas said, and it matches
CGE/view3dscene implementation too.

Regards,

Michalis

śr., 18 paź 2023 o 16:22 Andreas Plesch < <mailto:andreasplesch at gmail.com>
andreasplesch at gmail.com> napisał(a):

> 

> Hi Don,

> 

> Thanks.

> 

> > Andreas, if you have suggested prose for "explain that fogVisibility
corresponds to the visibilityRange field" then please send that.  We can at
least create a Mantis issue for eventual resolution.

> 

> The table 17.5 at

> 

>  <https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.pr>
https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4-IS.pr

> oof/Part01/components/lighting.html#t-foginterpolant

> 

> mentions 'fogVisibility' but the term is not clearly defined.

> 

> The bullet list above the table has

> 

> - fogInterpolant is the fog interpolant, see Table 17.5 for calculation.

> - fogDistance is the distance from point on geometry to viewer's 

> position, in coordinate system of current fog node.

> - fogColor is the currently bound fog's color.

> 

> Let me suggest expanding that list with an additional line:

> 

> - fogVisibility (Table 17.5) is the currently bound fog's 

> visibilityRange, in the same coordinate system as fogDistance.

> 

> Michalis may have background on introducing the 'fogVisibility' term.

> Perhaps it is an attempt to decouple from the fog node to allow 

> flexible use of world or local coordinate systems for computations.

> 

> Best, Andreas

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