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Subject: RE: [cgmo-webcgm] Model Profile version in Chapter 6?
Let's make the due date September 14. Rob -----Original Message----- From: Lofton Henderson [mailto:lofton@rockynet.com] Sent: Monday, August 29, 2005 9:23 AM To: Robert Orosz; cgmo-webcgm@lists.oasis-open.org Subject: RE: [cgmo-webcgm] Model Profile version in Chapter 6? 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.
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