seth@miro.Berkeley.EDU (Seth Teller) (02/20/91)
In <44374@ut-emx.uucp> blake@ccwf.cc.utexas.edu (Blake Freeburg) writes: > I need some help using the SG lib on an RS/6000 and drawing a nurbs surface. > blake In <216@usna.NAVY.MIL>, Prof. David F. Rogers (Aerospace) <dfr@usna> writes: >> You don't need to use the SGI hardware to do this efficiently. Look in >> the December issue of Computer Aided Design for the paper Dynamic Rational >> B-spline Surfaces by Rogers and Adlum. It's all there for the taking. >> Dave Rogers this seems like poor (or at least not necessarily good) advice. hundreds of person-hours have gone into the sgi library so that people like blake can draw surfaces with simple procedure calls. why refer them to something unknown (with all due respect)? i didn't write the sgi nurbs implementation, but i have several years' experience working with it and contributing to the development of its interface and functionality. please don't sell it so short. seth ps blake, example code is on its way.
dfr@usna.navy.mil (Prof. David F. Rogers (Aerospace) <dfr@usna>) (02/21/91)
In article <1991Feb19.221646.19527@agate.berkeley.edu> seth@miro.Berkeley.EDU (Seth Teller) writes: >In <44374@ut-emx.uucp> blake@ccwf.cc.utexas.edu (Blake Freeburg) writes: >> I need some help using the SG lib on an RS/6000 and drawing a nurbs surface. >> blake > >In <216@usna.NAVY.MIL>, Prof. David F. Rogers (Aerospace) <dfr@usna> writes: >>> You don't need to use the SGI hardware to do this efficiently. Look in >>> the December issue of Computer Aided Design for the paper Dynamic Rational >>> B-spline Surfaces by Rogers and Adlum. It's all there for the taking. >>> Dave Rogers > >this seems like poor (or at least not necessarily good) advice. hundreds >of person-hours have gone into the sgi library so that people like blake >can draw surfaces with simple procedure calls. why refer them to something >unknown (with all due respect)? > >i didn't write the sgi nurbs implementation, but i have several years' >experience working with it and contributing to the development of its >interface and functionality. please don't sell it so short. > Because I have tried it and don't like it. It is too restrictive, the explanation in the manual is terrible, etc. And incidentally I am a fan of SGI's and have a whole room full of them. Dave Rogers . > . . . . . . . . . . . . . . . . . . . . . . .. . .
seth@miro.Berkeley.EDU (Seth Teller) (02/22/91)
Blake Freeburg wrote >> I need some help using the SG lib on an RS/6000 and drawing a nurbs surface. David F. Rogers wrote > You don't need to use the SGI hardware to do this efficiently. Look in > the December issue of Computer Aided Design for the paper Dynamic Rational > B-spline Surfaces by Rogers and Adlum. It's all there for the taking. Seth Teller wrote > this seems like poor (or at least not necessarily good) advice. hundreds > of person-hours have gone into the sgi library so that people like blake > can draw surfaces with simple procedure calls. why refer them to something > unknown (with all due respect)? > > i didn't write the sgi nurbs implementation, but i have several years' > experience working with it and contributing to the development of its > interface and functionality. please don't sell it so short. David F. Rogers wrote > Because I have tried it and don't like it. It is too restrictive, the > explanation in the manual is terrible, etc. Seth Teller responds: i'll say this (again) as politely as i can manage. you're recommending that an inexperienced person, _in isolation_, transcribe an unknown, unproven technical paper into _isolated_ software, rather than use working, released, supported software. your justifications are: 1) an opinion; > Because I have tried it and don't like it. 2) an essentially meaningless (and in my opinion unfounded) statement; > It is too restrictive, 3) a (possibly legitimate) complaint _about the documentation_! > the explanation in the manual is terrible, etc. now, lots of people read this group and form opinions from it. in my opinion, your posting ill-serves them. most people who wish to render surfaces do not write papers about surface rendering. the gl nurbs implementation is fine for, say, 95%+ of its users. technical people may perhaps desire something different. my point: it is simply a _disservice_ to the original poster to send him off on several weeks' worth of hell wading through Yet Another Spline Paper, instead of sending him what he originally _asked_ for: some code to get surfaces drawn. take care. seth ps. some technical points: the sgi implementation does view-dependent subdivision. sgi hardware is used for low-level evaluation, but obviously such evaluation works by another mechanism on non-sgi boxes. therefore not even the gl "needs" sgi hardware to draw nurbs.
woo@basia.csd.sgi.com (Mason Woo) (02/23/91)
In article <225@usna.NAVY.MIL>, dfr@usna.navy.mil (Prof. David F. Rogers (Aerospace) <dfr@usna>) writes: |> Because I have tried it and don't like it. It is too restrictive, the |> explanation in the manual is terrible, etc. |> Technical Education and Technical Publications are working in conjunction to improve the quality of the NURBS documentation and course material. As of March, NURBS will now be a part of our Graphics 2 course (admittedly an expensive solution at $1200). We also have created a NURBS tutorial (similar to the 3-D projection and other tutorials) for the class. |> And incidentally I am a fan of SGI's and have a whole room full of them. |> |> Dave Rogers |> I knew that. Yay, Dave. Mason Woo (415) 962-3314 Internet: woo@SGI.COM Silicon Graphics Computer Systems "Dysfunctional and proud of it."