[x3d-public] Spec problem with 3D texture axes: wrong-handed coordinate system

Wed Sep 1 22:26:49 PDT 2021

Hi, Vince –

Good job. Works for me!

*	Dick

/******************************************

| Richard F. Puk, Ph.D., President

| Intelligraphics Incorporated

| 7644 Cortina Court

| Carlsbad, CA  92009-8206

| Tel: +1-760-753-9027  Mobile:  +1-760-809-9027

| Email:   <mailto:puk at igraphics.com> puk at igraphics.com

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From: x3d-public <x3d-public-bounces at web3d.org> On Behalf Of vmarchetti at kshell.com
Sent: Wednesday, September 1, 2021 9:23 PM
To: X3D-Public <x3d-public at web3d.org>
Subject: Re: [x3d-public] Spec problem with 3D texture axes: wrong-handed coordinate system

The latest version of the figure, incorporating these changes :

On Aug 31, 2021, at 2:19 PM, Brutzman, Donald (Don) (CIV) <brutzman at nps.edu <mailto:brutzman at nps.edu> > wrote:

Dick and I reviewed this closely and said the following in Mantis 978:

https://www.web3d.org/member-only/mantis/view.php?id=978

Possible changes to figure:

a. Need coordinates indicated for R axis,
b. Might omit R=0 and R=1/2 (as shown in existing specification),

Possible changes to prose:

c. (s,t,r) should be ordered as (r,s,t), or
d. Likely should use (u,v,w) instead to match common convention as shown in
   https://en.wikipedia.org/wiki/UVW_mapping (UVW mapping) or
   we informally found in OpenGL specification.

Recommend amending figure lower-case u,v,w – again thanks Vince.

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 http://faculty.nps.edu/brutzman

From: vmarchetti at kshell.com <mailto:vmarchetti at kshell.com> 
Sent: Monday, August 30, 2021 10:07 AM
To: X3D-Public <mailto:x3d-public at web3d.org> 
Cc: Brutzman, Donald (Don) (CIV) <mailto:brutzman at nps.edu> ; Nicholas Polys <mailto:npolys at vt.edu> ; Richard F. Puk <mailto:puk at igraphics.com> 
Subject: Re: [x3d-public] Spec problem with 3D texture axes: wrong-handed coordinate system

NPS WARNING: *external sender* verify before acting.

Dick 

At this time I am about 66% confident that the figure I sent on Aug 27 is correct.

-- for the figure, as in the original, ignore the 2 cross sections on the left that have no relevance to handedness.

The original figure, with it's assignment of coordinates (1 0 0) as a point on the S axis, and (0 1 0) as a point on the T axis ; and the text

which considers  (s t r ) as being a coordinate tuple, it appears the intent is the S T R can be considered renaming of X Y Z axes:

X --> S

Y --> T

Z --> R

If I cross out the S T R labels from the figure , and scribble in X Y Z accordingly, the figure I drew appears right handed.

Another way to "look" : If S T R is intended to be a right-handed system. then , by cyclic rearrangement of axes, so is T-R-S and viewed in this order, the figure I submitted (still) looks right-handed.

Vince

On Aug 30, 2021, at 12:09 PM, <puk at igraphics.com <mailto:puk at igraphics.com> > <puk at igraphics.com <mailto:puk at igraphics.com> > wrote:

Hi –

It still look left-handed to me :^( I suggest exchanging the S and T labels and coordinates leaving the R label and coordinates where they are.

*         Dick

/******************************************

| Richard F. Puk, Ph.D., President

| Intelligraphics Incorporated

| 7644 Cortina Court

| Carlsbad, CA  92009-8206

| Tel: +1-760-753-9027  Mobile:  +1-760-809-9027

| Email:   <mailto:puk at igraphics.com> puk at igraphics.com

\****************************************** 

From: Brutzman, Donald (Don) (CIV) < <mailto:brutzman at nps.edu> brutzman at nps.edu> 
Sent: Sunday, August 29, 2021 11:50 PM
To:  <mailto:vmarchetti at kshell.com> vmarchetti at kshell.com; Richard F. Puk < <mailto:puk at igraphics.com> puk at igraphics.com>; 'Nicholas Polys' < <mailto:npolys at vt.edu> npolys at vt.edu>
Cc: John Carlson < <mailto:x3d-public at web3d.org> x3d-public at web3d.org>
Subject: RE: [x3d-public] Spec problem with 3D texture axes: wrong-handed coordinate system

Looks outstanding to me, we will review.  Thanks Vince.

p.s. if you created an X3D model to produce this, am happy to check it into version control  We have a section in the X3D archives for specification figures.

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br        <mailto:brutzman at nps.edu> 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> http://faculty.nps.edu/brutzman

From:  <mailto:vmarchetti at kshell.com> vmarchetti at kshell.com
Sent: Saturday, August 28, 2021 8:04 AM
To:  <mailto:x3d-public at web3d.org> X3D-Public
Subject: Re: [x3d-public] Spec problem with 3D texture axes: wrong-handed coordinate system

Attached is a revised Figure 33.1 for the X3D V4 specification under review.

This version of the figure was corrected to accurately match the description of the R S T coordinate axes as described in Sections 33.2.2 and 33.2.3 of  <https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/texture3D.html#f-3DTexture> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/texture3D.html

Vince Marchetti

<image001.png>

On Aug 27, 2021, at 9:58 PM,  <mailto:vmarchetti at kshell.com> vmarchetti at kshell.com wrote:

Upon evaluation, this figure attached to the Aug 27 email is inconsistent with the specification text Section 33.2.3

A corrected figure is forthcoming.

Vince Marchetti

On Aug 27, 2021, at 3:54 PM,  <mailto:vmarchetti at kshell.com> vmarchetti at kshell.com wrote:

Please evaluate whether attached figure meets needs of X3DV4 specification document

SVG (via Inkscape) format available upon request

Vince Marchetti

<x3dV4_Fig33_1.png>

On Aug 27, 2021, at 1:47 PM, Brutzman, Donald (Don) (CIV) < <mailto:brutzman at nps.edu> brutzman at nps.edu> wrote:

As noted in Mantis 978,  <https://www.web3d.org/member-only/mantis/view.php?id=978> https://www.web3d.org/member-only/mantis/view.php?id=978

The following figure shows a left-handed coordinate system.

 <https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/texture3D.html#f-3DTexture> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/texture3D.html#f-3DTexture

<54CB4E59BAA24518B7648236A2468E3C.png>

Wondering how to fix – swap 2 axes can work.  Perhaps there is a commonly used diagram in OpenGL (or elsewhere) we might adopt and adapt?

Any volunteers to do this (pretty please) to improve X3D4 specification?

all the best, Don
-- 
Don Brutzman  Naval Postgraduate School, Code USW/Br        <mailto:brutzman at nps.edu> 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> http://faculty.nps.edu/brutzman

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