[ont.events] Graphics Seminars

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.