voula@utcsri.UUCP (Voula Vanneli) (02/20/85)
University of Toronto Department of Computer Science (SF = Sandford Fleming Building, 10 King's College Road) GRAPHICS SEMINAR - Tuesday, February 26, 4 p.m., SF 1105 Ephraim Glinert University of Washington "Experiments in the Design of Interactive Graphical Programming Environments" Abstract For many people, learning to program a computer is arduous: often, the attempt is eventually abandoned in frustration. The PICT systems presented here, and the underlying philoso- phy which they embody, are an attempt to alleviate this situation. They are a radical departure from current pro- gramming styles, including so-called graphical ones, in which the visual element is made central. N.B. Change of Location for Graphics Seminar-Friday, Feb. 22, 11a.m. To be held in Room SF 3202. University of Toronto Department of Computer Science (GB = Galbraith Building, 35 St. George) GRAPHICS SEMINAR - Wednesday, February 27, 3 p.m. GB 244 Tony DeRose University of California at Berkeley "Geometric Continuity for Parametric Curves and Surfaces" Abstract In this talk, I'll define geometric continuity of arbitrary order n(Gn) for parametric curves and surfaces, and present an intuitive development of constraints equations that are necessary and sufficient for it. the constraints result from a simple principe and reparametrization in conjunction with the univariate chain rule for curves, and the bivariate chain rule for surfaces. The constraints provide for the introduction of quantities known as shape parameters, which can be made available to a designer in a computer-aided design environment. More specifically, if two curve seg- ments are to meet with Gn continuity, n shape parameters may be introduced. For surfaces, the use of the constraints for Gn continuity provides for the introduction of n(n + 3) shape functions, defined along the boundary between two sur- face patches.