jrm@delta.ma.adfa.oz.au (John R Marley) (05/20/91)
I have DKBtrace version 2.11 running on our Apollo DN10000 and wish to trace a
few teapots. I have the data describing the thing, but it uses Bezier patches.
I can convert the Bezier patches to heaps of smooth shaded triangles, but
calculating the vertex normals will be a bit of a #$%^&*.
I guess what I'm asking is can it be done in this version without triangles?
What sort of shapes can on get out of the QUARTIC primitive? The body and lid
of the teapot are surfaces of rotation, and the handle and spout are two
mirror-image patches, if that's any help.
OK, so I work in a Maths Department - I'm a programmer not a Lecturer...
Thanks in advance..
--
John Marley | Maths Dept, Uni College, |
jrm@maadfa.adfa.oz.au | U.N.S.W., A.D.F.A., | =8^)
ph : +61 6 2688882 | Canberra, Australia. |tbissett@nstar.rn.com (Travis Bissett) (05/20/91)
jrm@delta.ma.adfa.oz.au (John R Marley) writes: > > I have DKBtrace version 2.11 running on our Apollo DN10000 and wish to trace > few teapots. I have the data describing the thing, but it uses Bezier patche > I can convert the Bezier patches to heaps of smooth shaded triangles, but > calculating the vertex normals will be a bit of a #$%^&*. > > I guess what I'm asking is can it be done in this version without triangles? > What sort of shapes can on get out of the QUARTIC primitive? The body and li > of the teapot are surfaces of rotation, and the handle and spout are two > mirror-image patches, if that's any help. > > OK, so I work in a Maths Department - I'm a programmer not a Lecturer... > There are 2 Q&D approaches that might work for you -- create the triangles in Sculpt3-D, using the surface of rotation feature to make the triangles. Or, you might search out someone with the Video Toaster. I recall Allen Hastings demoed Lightwave with some fabulous "environmental mapping" on a tumbling Utah Teapot -- I bet that's the same teapot (used as a logo by NCGA I think). Or do you Down Under call it a "billy"? Hope these two suggestions are useful. Travis -- tbissett@nstar.rn.com -- Travis Bissett NSTAR conferencing site 219-289-0287/317-251-7391 internet: tbissett@nstar.rn.com 1300 newsgroups - 8 inbound lines uucp: ..!uunet!nstar.rn.com!tbissett 99 file areas - 4300 megabytes --- backbone news & mail feeds available - contact larry@nstar.rn.com ---
ins940x@monu4.cc.monash.edu.au (mr s.e. raik) (05/20/91)
Dont know how on earth you could do it, but I'd sure like to see
the final product!
|\/|ork.tmkk@uiuc.edu (K. Khan) (05/20/91)
Some quick questions: What is DKBtrace, and what is Rayshade? Are these commercial packages, public domain, shareware? Where can I obtain them? Thanks!
andreww@uniwa.uwa.oz (Andrew John Williams) (05/21/91)
In either 'Computer Graphics '87' or 'Eurographics 88' there is an article which uses 'the' teapot as an example object, and states where its specifications can be found. Christopher Jam
erich@eye.com (Eric Haines) (05/22/91)
In article <JRM.91May20122241@delta.ma.adfa.oz.au> jrm@delta.ma.adfa.oz.au (John R Marley) writes: > >I have DKBtrace version 2.11 running on our Apollo DN10000 and wish to trace a >few teapots. I have the data describing the thing, but it uses Bezier patches. >I can convert the Bezier patches to heaps of smooth shaded triangles, but >calculating the vertex normals will be a bit of a #$%^&*. It's not that hard to compute the normals - two more power vectors to get surface tangent u & v vectors, then take the cross product of these to get the normal. Things do fall apart at the center of the lid, where the normals go to zero or somesuch (I solve this by just testing for these special case guys). The code is a part of the SPD 3.0 package, which generates the teapot at any resolution you like. The SPD package is available via anonymous FTP from: weedeater.math.yale.edu [130.132.23.17] among others. For those without FTP access, write to the netlib automatic mailer: research!netlib and netlib@ornl.gov are the sites. Send a one line message "send index" for more information, or "send haines from graphics" for the latest version of the SPD package. It'll automatically send you the source. Eric
lance@motcsd.csd.mot.com (lance.norskog) (05/22/91)
Send mail to netlib@ornl.gov with this line: send haines from graphics You'll get a shar of graphics model generators, including the teapot tesselated to various depths.
fons@cwi.nl (Fons Kuijk) (05/24/91)
In article <1991May20.163606.1522@ux1.cso.uiuc.edu> tmkk@uiuc.edu (K. Khan) writes: > >Some quick questions: What is DKBtrace, and what is Rayshade? Are these >commercial packages, public domain, shareware? Where can I obtain them? > >Thanks! One more: What is a teapot? ------------------------------------------------------------------------