RE: [cgmo-webcgm] Model Profile version in Chapter 6?

[Lofton Henderson <lofton@rockynet.com>]

At 09:06 AM 8/29/2005 -0600, Robert Orosz wrote:
>Lofton,
>
>Yes, I'll accept that action item.  Do we need Dave to create one, or is
>there a way that I can create it?

Dave should put it in the AI list that he maintains as part of the 
Agenda/Minutes.

Would you like to pick a Due Date now, so that Dave can include that in the AI?

Thanks,
-Lofton.


>-----Original Message-----
>From: Lofton Henderson [mailto:lofton@rockynet.com]
>Sent: Saturday, August 27, 2005 9:50 AM
>To: Robert Orosz; cgmo-webcgm@lists.oasis-open.org
>Subject: RE: [cgmo-webcgm] Model Profile version in Chapter 6?
>
>
>At 05:42 PM 8/26/2005 -0600, Robert Orosz wrote:
> >Lofton,
> >
> >GREXCHANGE 2.9 has the same error with respect to NUBS and NURBS in the
> >Model Profile :-(.
> >
> >I would prefer that we require the clamped form.  Implementation is easier.
>
>I agree.  If ATA doesn't want "clamped", they can always remove that
>restriction in their cascaded profile definition.
>
>Btw, do you accept the AI to look for further divergence, between WebCGM MP
>and CGM:1999 MP?
>
>-Lofton.
>
>
> >-----Original Message-----
> >From: Lofton Henderson [mailto:lofton@rockynet.com]
> >Sent: Friday, August 26, 2005 5:32 PM
> >To: Robert Orosz; cgmo-webcgm@lists.oasis-open.org
> >Subject: Re: [cgmo-webcgm] Model Profile version in Chapter 6?
> >
> >
> >Hi Rob,
> >
> >Taking your questions a little out of order:
> >
> >At 12:16 PM 8/26/2005 -0600, Robert Orosz wrote:
> > >[...]
> > >I have a vague recollection that an earlier version of the Model Profile
> >did
> > >not require clamped splines which leads me to wonder, are we listing the
> > >latest Model Profile in Chapter 6?
> >
> >Yikes!
> >
> >I just checked my paper copy [1] of ISO 8632:1999 Part 1, Annex I
> >(PPF).  In the MP, it is the clamped form.  This agrees with the ISO-hosted
> >online (PDF) version at [2].  It agrees also with p1.htm, which is an
> >unofficial HTML version that was given to me by ISO and which I have in my
> >old editor's directories.  So "clamped" must be considered to be the latest
> >MP PPF.
> >
> >[1] paper CGM:1999
> >[2]
> >http://isotc.iso.org/livelink/livelink/fetch/2000/2489/Ittf_Home/PubliclyAv
>a
> >ilableStandards.htm
> >[3] p1.htm
> >
> >It does NOT agree with the MP of WebCGM 1.0 [4], nor with draft 2.0 [5]:
> >
> >[4] http://www.w3.org/TR/REC-WebCGM/REC-04-CGM-Profile.html
> >[5]
> >http://www.oasis-open.org/committees/download.php/14161/WebCGM20-20050804.z
>i
> >p
> >
> >It's hard to guess where this happened.  But I recall, in the foggy past
> >(probably about 6 years ago), we changed the PPF format from check- box
> >style to YES/NO on the Required/Permitted/Prohibited line (to avoid the
> >funny empty-box and checked-box characters in the WebCGM HTML
> >text).  Someone must have made the error then (let's blame John!).
> >
> >The good news:  since 1.0 didn't allow NUBS/NURBS, the error in
> >transcription of the MP doesn't affect 1.0.  We do need to consider whether
> >we want to restrict to the clamped form for 2.0 (seems reasonable -- the
> >clamped cubic NUBS/NURBS would be a subset of all cubic ones, which should
> >mean easier viewer implementation.  Does "clamped" suffice for the
> >potential users?).
> >
> >The bad news:  did ATA propagate that MP error?  and, are there other MP
> >PPF errors?
> >
> > >I'll try and review more of the PPF to
> > >see if there are other inaccuracies.
> >
> >That would be terrific -- very timely and much needed now.  (If you are
> >unable to do it, please let me know -- we'll need to give it as an AI
> >assignment to someone.)
> >
> > >I have an open action item to generate some test cases with NUBS for the
> > >test suite.  In preparation for doing so, I went to sections T.19.24 and
> > >T.19.25 of the WebCGM PPF to review the requirements.  Both sections
>state
> > >"Same as Model Profile: Yes", however, the Model Profile half of each
> > >section is incorrect.  The Model Profile requires clamped splines which
> > >means that the first four knots must be identical and the last four knots
> > >must be identical.  This requirement is not listed in the WebCGM 2.0
>draft
> > >PPF.  Section 6.1 does say, "In case of discrepancies, the Model Profile
>in
> > >ISO/IEC 8632:1999 shall take precedence." however, I suspect most people
> > >won't take the time to cross check with the Model Profile.
> >
> >Probably not.  However, as I said -- the normative content of WebCGM 1.0 is
> >unaffected.  And in any case, the "discrepancies" clause means that
> >(formally) "clamped" rules in the MP column.  We will of course fix the
> >content of the MP in the 2.0 PPF.  If anyone thinks that 2.0 should NOT be
> >"same as MP" (i.e., that we should remove the "clamped" restriction of the
> >MP), he should bring it up as an issue.
> >
> >Thanks,
> >-Lofton.