[X3D-Public] important questions regarding Units proposal

Mon Jun 20 10:07:12 PDT 2011

Hi --

Those two measures are not currently used directly in any nodes in X3D. To
add them, you should propose new nodes that do use those measures.
Otherwise, you can use those measures by embedding their information in
Metadata nodes and using scripts to apply them.

  -- Dick

/*****************************************
* Richard F. Puk, Ph.D.
* President, Intelligraphics Incorporated
* 7644 Cortina Court
* Carlsbad, CA  92009
* Tel:  1-760-753-9027 E-Mail: puk at igraphics.com
\*****************************************

> -----Original Message-----
> From: geovrml [mailto:geovrml at geovrml.com]
> Sent: Monday, June 20, 2011 8:41 AM
> To: Richard Puk
> Cc: 'Don Brutzman'; npolys at vt.edu; 'Myeong Won Lee'; 'Leonard Daly'; 'X3D
> Graphics public mailing list'
> Subject: Re: [X3D-Public] important questions regarding Units proposal
> 
> Hi all,
> 
> I know it may seem weird when talkin about x3D, but it's of importance to
my
> explosimetry/chemistry works, and may be a function of space (ie
> depth/altitude) or environment (weather ...), so it may become for others
:
> 
> Pressure : Pa
> Temperature: °K
> 
> Besides, those two beasts of measure come in very ... very different
flavors ... a
> pain to deal with in the end.
> 
> Eric Maranne.
> 
> Le 20/06/2011 01:56, Richard Puk a écrit :
> > Hi, Don --
> >
> > With the exception of "time" (i.e., seconds), I believe that all of the
units are
> listed. Please submit comments if you think that there are others that
should be
> mentioned. I systematic search identified only the base units and the
derived
> units.
> >
> >    -- Dick
> >
> > /*****************************************
> > * Richard F. Puk, Ph.D.
> > * President, Intelligraphics Incorporated
> > * 7644 Cortina Court
> > * Carlsbad, CA  92009
> > * Tel:  1-760-753-9027 E-Mail: puk at igraphics.com
> > \*****************************************
> >
> >
> >
> >
> >> -----Original Message-----
> >> From: Don Brutzman [mailto:brutzman at nps.edu]
> >> Sent: Sunday, June 19, 2011 2:51 PM
> >> To: npolys at vt.edu
> >> Cc: Richard F. Puk; Myeong Won Lee; Leonard Daly; X3D Graphics public
> >> mailing list
> >> Subject: Re: important questions regarding Units proposal
> >>
> >> cc: working group
> >>
> >> On 6/19/2011 2:02 PM, npolys at vt.edu wrote:
> >>> It appears the units proposal is now in 3.3
> >> Original proposal and slides:
> >>
> >>
> http://www.web3d.org/membership/login/memberwiki/index.php/X3D_Physic
> >> a
> >> l_Units_Proposal
> >>
> http://web3d.org/membership/login/groups/Korea%20Web3D%20Forum/1%28
> >> myeong%29Unit_VR.pdf
> >>
> >> Specification changes are in the Concepts section and also Core
> >> Component
> >>
> http://www.igraphics.com/Standards/ISO_IEC_19775_1_2_PDAM1_Candidate_
> >> 2011_05_12/Part01/concepts.html
> >>
> http://www.igraphics.com/Standards/ISO_IEC_19775_1_2_PDAM1_Candidate_
> >> 2011_05_12/Part01/components/core.html
> >>
> >> 4.3.6 Standard units and coordinate systems
> >>
> >> Standard units are modifiable from the following defaults
> >>
> >> 	angle 	radian
> >> 	force 	newton
> >> 	length 	metre
> >> 	mass 	kilogram
> >>
> >> which in turn lead to the following derived units:
> >>
> >> 	acceleration 	length/second2
> >> 	angular_rate 	angle/second
> >> 	area 	length2
> >> 	speed 	length/second
> >> 	volume 	length3
> >>
> >> ======================
> >> 7.2.5.5 UNIT statement
> >>
> >> X3D applications may explicitly alter the initial base units within
> >> an X3D world by inserting UNIT statements defining the
> >> characteristics of the new default base units. At most one UNIT
statement
> shall be provided for each base unit type.
> >> Only the UNIT statements in the root file apply to an X3D world. If
> >> no UNIT statements are provided, the initial base units as specified
> >> in 4.3.6 Standard units and coordinate system shall apply.
> >>
> >> UNIT statements contained in X3D files referenced by Inline nodes or
> >> contained in X3D files consisting of EXTERNPROTO bodies shall be used
> >> to align effected units to the base units of the root file before the
> >> referenced X3D file content is incorporated in the X3D world.
> >>
> >> UNIT statements may only be contained in X3D worlds created for X3D
> >> version
> >> 3.3 or later (as specified in the Header statement). If a version of
> >> 3.2 or earlier is specified in conjunction with UNIT statements, the
browser
> shall fail.
> >>
> >> A change in a base unit is specified by UNIT statements at the top of
> >> the file preceding any element content but in the statement order
> >> specified in 7.2.5.1 Organization. The form of the UNIT statement is:
> >>
> >>      UNIT<category>  <name>  <conversion_factor>
> >>
> >> where<category>  is a string specifying one of the categories in
> >> Table 4.2, <name>  is a string that does not contain whitespace that
> >> provides a name for the new default base unit, and<conversion_factor>
> >> is a positive double precision value that converts the new default
> >> base unit to the initial base unit specified in Table 4.2.
> >> ======================
> >>
> >> Dick:  shouldn't we be listing other units available in our
specification?
> >> Or at least pointing to the relevant ISO specification for these
enumerations?
> >> i couldn't find either in the proposed change.
> >>
> >> 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, virtual worlds, underwater robots
http://faculty.nps.edu/brutzman
> >
> > _______________________________________________
> > X3D-Public mailing list
> > X3D-Public at web3d.org
> > http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> >
> >