Last Updated: October 25, 2011

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This pages contains the slides I used in some talks I have given.

• Why Multivariate Polynomial Data Interpolation Goes Bad, October 27, 2011. This is a talk I gave at the SIAM/ACM GDM conference.
• Linear Methods for Degree Recution of Bézier Curves with Geometric Continuity, October 24, 2011. This is a talk I gave at the SIAM/ACM GDM conference.
• Issues with Multivariate Polynomial Interpolation, October 6, 2009. This is a talk I gave at the SIAM/ACM GDM conference on issues (and solutions) multivariate data interpolation with polynomials. The talk is fairly high level; details on what we did are not in the talk.
• Flank Millable Surface Design with Conical and Barrell Tools. June 27, 2008. This is a talk I gave at CAD 08 on work done by Chenggang Li for his PhD that I co-supervised with Prof Sanjeev Bedi.
• Proving the Lane-Riesenfeld Algorithm. June, 2005. This is a CGL talk based on a talk that Ron Goldman gave at a Dagstuhl seminar.
• Bivector Continuity. May, 2005. This is a talk that I gave at a Dagstuhl seminar.
• Computing u,v Coordinates. This is a CGL talk I gave on how to invert a bilinear map. We thought we had a slick, geometric method, but alas, the geometry was wrong.
• Using geometric algebra to computer singularities in 3D vector fields. January 9, 2002.
  This is a CGL talk I gave describing my work with Alyn Rockwood on using octrees and geometric algebra to find singularities in 3D vector fields.
• A Geometric Interpretation of Bézier Stability November 29, 2001.
  This is a talk I gave to CGL on Bézier stability. This talk is based on a talk by Helmut Pottmann at the 4th Dagstuhl Workshop on Geometric Design. Comparisons to monomials and relative analysis are my extensions, so send me the blame and send Helmut the praise. See also the last slide, which contains a "study" for my foray into the Fine Arts.
• Are Isophotes and Reflection Lines the Same? October 11, 2000.
  This is a talk I gave to the CGL on isophotes and reflection lines. This talk is essentially the same talk as given by Hogel Theisel at the 1999 SIAM Conference on Geometric Design in Albequerque, New Mexico. My thanks to Hogel for sending me the PostScript for his slides, from which I extracted all of the figures in this talk.
• Geometric Algebra October 6, 2000.
  A variation on the SIGGRAPH talk that I gave at Alias|wavefront in Toronto. There is an associated Matlab file that should be renamed GAD.m after downloading. You will also need a copy of GABLE, which in turn needs Matlab to run (version 5.2 or later).
• GABLE July 25, 2000. Also available as pdf
  A presentation I gave for a course on geometric algebra at SIGGRAPH 2000. I did the presentation jointly with Leo Dorst, who demonstrated in Matlab the ideas I presented on these slides. To get the most out of the slides, you should download GABLE, and run the GAD file (GA Demo) at the points marked on the slide. Note that you will need Matlab to run GABLE.
• Polynomial Precision Triangular Interpolants July 3, 2000.
  A talk I gave at the Fifth Conference on Mathematical Methods for Curves and Surfaces in Oslo.
• Multiresolution Editing of Pasted Surfaces June 30, 2000.
  A talk I gave at the Fifth Conference on Mathematical Methods for Curves and Surfaces in Oslo.
• Geometric Algebra: An Introduction January 5, 2000.
  A introductory talk I gave on Geometric Algebra to the CGL. This is a short version of the talk I gave the previous year in Saarbruecken.
• Surface Pasting November 4, 1999.
  A talk on surface pasting that I gave at the 1999 SIAM Conference on Geometric Design.
• Polynomial Precision Triangular Interpolants (compressed PostScript, 328k), October 1, 1999.
  A talk about functional triangular interpolants that achieve polynomial precision by adjusting continuity between patches.
• Geometric Algebra: An Introduction September 21, 1999.
  A introductory talk I gave on Geometric Algebra when I visited the University of Saarbruecken.
• Cylindrical Surface Pasting (compressed PostScript, 1100k), May 22, 1999.
  Dagstuhl Seminar. A talk about a cylindrical surface pasting.
• Cylindrical Pasting, March 20, 1999.
  A discussion on the cylindrical pasting research in CGL. This talk was given to UToronto DGP group when they visited our lab.
• How To Give a Talk Talk, November 24, 1998.
  A web version of the alternative version of the How To Give a Talk talk that I gave to our graphics lab at Waterloo. This talk gives some tips on how to give a talk, using a talk on CAVD (Computer Aided Violin Design) as an example.
• An Improved Side-Vertex Triangle Mesh Interpolant (compressed PostScript, 670k), June 18, 1998.
  GI 1998. A talk about a local side-vertex triangular interpolant that has improved shape.
• Pasting Research, May 22, 1998.
  An updated version of the talk given to DGP.
• Pasting, March 21, 1998.
  A overview of the current research on pasting in CGL. This talk was given to UToronto DGP group when they visited our lab.
• Radiosity, February 18, 1998.
  An introductory talk that I gave to the Computer Science Club at Waterloo as background for their radiosity programming project.
• How To Give a Talk Talk, February 4, 1998.
  A web version of the How To Give a Talk talk that I gave to our graphics lab at Waterloo. This talk gives some tips on how to give a talk.
• Modeling with Triangular Surface Patches (PostScript, 2 Meg) A mis-titled talk, it should be "A Parametric Hybrid Triangular Surface Interpolant", this is an updated version of the Vanderbilt talk, with a few corrections, etc. Also, this talk is in color, so you'll probably only be able to view it on a color display, and printing it might not be such a good idea.
• World Space Surface Pasting (compressed PostScript, 7 Meg) A talk about a surface pasting user interfaces that one of my students developed.
  This file is PostScript that was generated by showcase, and it is HUGE. And color.
• Writing Your Thesis An informal talk I gave to our graphics lab discussing common errors I find when I read Master's and PhD theses. Note that this was not a talk about writing; rather, I was just describing errors that I commonly mark when reading theses.
• Modeling with Triangular Surface Patches February, 1997
  A slightly updated version of the Vanderbilt talk. These are color slides.
• Modeling with Triangular Surface Patches November, 1996
  A talk I gave while visiting Vanderbilt University. In this talk, I discuss my latest research (done jointly with my student Matthew Davidchuk) on triangular surface fitting.
• Hyperbolic Geometry September, 1996
  An informal talk I gave to our graphics lab at Waterloo. In this talk, I discuss the Poincare model of the hyperbolic plane, it's relation to some of Escher's pictures, and describe a Tcl script I wrote for drawing Escher-style sketches.
• Triangular Surface Fitting July, 1996
  This talk was given at the University of Kaiserslautern. In this talk, I discuss some of the issues related to triangular surface fitting. This file is about 2 Megabytes because there are PostScript versions of the color slides I showed during the talk.
• Algorithms from Blossoms July, 1996
  This talk was given at the University of Kaiserslautern. An expansion of the talk I gave a the Curves and Surfaces conference in Chamonix, in this talk I discussed how to create efficient algorithms from blossom equations.
• Sablonniere Type Composition Algorithms June, 1996
  I gave this talk at the Curves and Surface Conference, in Chamonix, June 1996. A talk noting the similarity in speedups to basis conversion algorithms and speedups to polynomial composition algorithms.
• Programming Support for Blossoming May, 1996
  Wayne Liu gave this talk at GI '96. He made his slides with CorelDRAW!, which created non-conforming PostScript. I remade the slides in LaTeX, reproducing most, but not all, of the figures. What you see here is the LaTeX version.
• Coordinate Free Geometry April, 1996
  An informal talk I gave to our graphics lab at Waterloo. This talk provides motivation for using a geometry ADT. The ADT mentioned in this talk was originally implemented by Tony DeRose; I ported it to ANSI; and several ports have been made to C++.
• Optimal Polynomial Composition November, 1995
  This talk was given at the 1995 SIAM Conference in Nashville, TN. This talk discusses an optimal polynomial composition algorithm. This work has been accepted for publication to ACM TOG.
• Modeling with Triangular Bézier Patches February, 1995
  A talk I gave at Purdue on triangular surface fitting. None of the color slides appear here in the PostScript.
• Generalized Polynomial Composition February, 1995
  A second talk I gave at Purdue. I drew a couple of figures by hand, so they're missing from the slides.
• How to give a talk March, 1993
  An informal talk I gave to our graphics lab at Waterloo. This talk gives some tips on how to give a talk. Note that the URL mentioned at the end of the talk is restricted to CGL machines.