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

[Robert Orosz <roboro@AUTO-TROL.com>]

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?

Rob

-----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.