Meeting Agenda

Wednesday, June 18^th, 1997

Location:

DC 1304

Time:

13:30

Chair:

Balasingham Balakumaran

1. Adoption of the Agenda - additions or deletions

2. Coffee Hour

Coffee hour this week:

Glenn Evans

Coffee hour next week:

???

3. Next meeting

Date:

June 25^th, 1997

Location:

DC 1304

Time:

13:30

Chair:

Richard Bartels

Technical presentation:

Balasingham Balakumaran

4. Forthcoming

Chairs:

1. Ian Bell(7/2)
2. Wilkin Chau (7/9)
3. Itai Danan (7/16)

Tech Presenters:

1. Richard Bartels (7/2)
2. Ian Bell(7/9)
3. Wilkin Chau (7/16)

5. Technical Presentation

Presenter:

Tali Zvi

Title:

Visualization of Vector Fields

Abstract:

In Scientific Visualization, often there is a need to visualize Vector Fields. Visualizing 3D vectors is not a trivial problem. A Vector field can include many kinds of information as magnitude, direction, torsion and curvature. I am am going to present two methods to visualize vector fields. These methods use the magnitude and direction of the vector to focus on highlighting regions of similar vector direction.

6. General Discussion Items

7. Action List

• Japanese Visitors
• Alias Visit Visit

8. Director's Meeting

9. Seminars

• A Parametric Hybrid Triangular Bezier Patch
  Matthew Davidchuk, graduate student, Dept. Comp. Sci., Univ. Waterloo
  Friday, June 20, 1997
  9:30-10:30 a.m.
  DC 1304
  ABSTRACT
  The triangular Bezier patch presents a natural primitive for modeling surfaces of arbitrary topology, but does not enjoy the same widespread use as the tensor product patch. Existing triangular Bezier patch interpolation schemes that are designed to fit surfaces to parametric data produce interpolants that suffer from noticeable visual flaws. Patch boundaries are often visible as creases in the resulting surface. Interpolation of functional data is simpler than interpolation of parametric data. However schemes such as the Clough-Tocher technique have many of the same visual flaws as parametric schemes. Foley and Opitz introduced an improvement over Clough-Tocher. Central to the Foley-Opitz scheme is the cross boundary construction that produces quadratically varying cross boundary derivatives. My work involves attempting to extend Foley's scheme to the parametric setting. Modifying this scheme requires the formulation of an extension to the standard rational blend technique. In addition to blending interior control points, boundary control points must also be blended to incorporate Foley's cross boundary construction, which relies on the natural parameterization of the functional setting. When interpolating irregularly scattered data and when increasing the tessellation of the data mesh, the new scheme shows improvement over representative parametric data fitting schemes. The quality of the resulting surfaces depended largely on the correlation between the normals and the triangles of the underlying mesh.
  
  

10. Lab Cleanup (until 14:30 or 5 minutes)