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

[vmarchetti at kshell.com]

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> <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:  puk at igraphics.com <mailto:puk at igraphics.com>
> \****************************************** 
>  
>  
>  
> From: Brutzman, Donald (Don) (CIV) <brutzman at nps.edu <mailto:brutzman at nps.edu>> 
> Sent: Sunday, August 29, 2021 11:50 PM
> To: vmarchetti at kshell.com <mailto:vmarchetti at kshell.com>; Richard F. Puk <puk at igraphics.com <mailto:puk at igraphics.com>>; 'Nicholas Polys' <npolys at vt.edu <mailto:npolys at vt.edu>>
> Cc: John Carlson <x3d-public at web3d.org <mailto: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       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 <http://faculty.nps.edu/brutzman>
>  
> From: vmarchetti at kshell.com <mailto:vmarchetti at kshell.com>
> Sent: Saturday, August 28, 2021 8:04 AM
> To: X3D-Public <mailto:x3d-public at web3d.org>
> 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 <https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/texture3D.html#f-3DTexture>
>  
> Vince Marchetti
>  
> <image001.png>
>  
>  
> 
>> On Aug 27, 2021, at 9:58 PM, vmarchetti at kshell.com <mailto: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, vmarchetti at kshell.com <mailto: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) <brutzman at nps.edu <mailto: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       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 <http://faculty.nps.edu/brutzman>
>>>>  
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