Last edited 4jul97 by gfrancis
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Projects in Computational Mathematics
UIMATH.grafiXlab, Summer 1997
Watch this site for abstracts and reports.
In the meantime, have a look at what we proposed to do
last summer. Some of it even got done.
Here is an index of projects that are getting underway this summer. They are
listed, last born first, by nickname and developer(s).
illiMBone ... Ulises Cervantes, John Estabrook, Matthew Stiak
In this first, exploratory phase of a larger
project we have enabled the
grafiXlab to multicast over 3 systems: the SGI Impact, the
Pentium Linux box, and a WindowsNT box. We are developing the
ability to originate broadcasts over Vosaic and multicasts
over the MBone. We will soon join the MSRI MBone project
to promote real-time electronic communication in mathematics.
CAVEgladiator... Kevin Vlack, UIUC; Alex Francis, U.Chicago; Umesh Thakkar, NCSA
This is an illiShell94 derived CAVE action game with physics based
ballistics, collisions and wave motions. Action is controlled by intuitively
obvious wand gestures. We shall use it for
controlled experiments to determine
the relative importance of head-tracking and stere-opsis in immersive
virtual enviroments. In a multifactorial block design we will test
naive subjects in each of the four modes and record their scores in
this fast paced, highly entertaining but difficult CAVE game developed
for Math 198 by Kevin Vlack. Cognitive scientist, Alex Francis at the University
of Chicago will consult on the statistical design and evaluation.
graviLens ... Birgit Bluemer, John Estabrook; Bob Patterson, Bill Sherman, NCSA
This real-time, interactive CAVE animation simulates the relativistic
distortion of space in the presence of a gravitational lens of variable mass.
Each vertex of the displayed scene is processed depending on the
position of the head and an object with variable mass. Thus the
load on the display resources is proportional to the complexity of
the scene displayed, but not, for instance, on the speed of navigation.
We are currently installing this project in the Marcus Thiebaux's
Virtual Director and illiConnecting it to the mutliprocessor
illiConnect ... John Estabrook; Alex Bourd, Qualcomm.
The goal of this project is to develop the prototype of a distributed
interactive VR application that takes advantage of SGI parallel hardware.
We are primarily interested in real-time, interactive simulations of
scientific processes which require substantial computation and are displayed
in immersive virtual environments (IVEs) such as the CAVE,
Immersadesk, and the Infinity Wall.
Currently, most such simulations run as batch jobs and dump results into
files, from which VR-viewers then read to create virtual scenes.
One is unable to see the simulation in progress---consequently, time is wasted
waiting to view calculations that may, in fact, have continued in an
With illiConnect, research and development teams
will greatly benefit from not only observing the progress of the
process in real-time, but also from the abilty to steer the
simulation in the desired direction.
illiVert ... Chris Hartman, John Sullivan
Continuation of the Minimax Sphere Eversion project. It will be adapted
to produce a high quality videotape for the International Congress of
Mathematics, Berlin 1998. It will also be prepared to go real-time over
StarTap from NCSA to Potsdam, Germany, August 1998.
philEver ... Matthew Stiak, Chris Hartman
We have created an OpenGL/Xlib GUI which is compatible with
the original (1993) RTICA, illiLevel. This tool uses
interpolating piece-wise cubic splines to sew a two-way collection of
level lines of a surface homotopy along the levels (smoothing a polygon),
across levels (rendering a smoothed surface), and through time (homotopy.)
The goal of this effort is a real-time interactive computer
animation of Tony Phillips' handrawn sphere eversion in a Scientific American
cover story in the 60's. This article inspired the physicist Bryce DeWitt to
design an alternative, arguably simpler homotopy, which could be an eversion
too. We expect to use the CAVE wholly immersive virtual environment to decide
the validity of this 30 year old conjecture.
churfStory ... Chris Hartman
The locus along which an surface, immersed in 3-space, intersects itself is called
its double locus. Typically, this is a set of double curves passing
through the triple points. A regular homotopy of the surface produces a homotopy
of the double locus. Generically, this succession of curves may be considered the
level sets of a 2-D surface in 4-space as a 3-D hyperplane slices through it.
In this project we visualize this surface. The details are accumulating
walkAbout ... Ulrike Axen
The Post-Euclidean Walkabout is a real-time
interactive CAVE application which takes you on a visit to the post-Euclidean
geometry of Gauss, Riemann, Klein, Poincare, and Thurston. Ever since its
premiere in the Virtual Reality Room at SIGGRAPH94 this has been the
perennial favorite to hundreds of CAVE visitors at VROOM, NCSA, EVL and
elsewhere. We have rewritten the code in OpenGL and restored the extensive
audification to recompile and run with the Virtual Sound Server 2.3 in the
current environment (12 R10000 CPU, 2 IR SGI Onyx CAVE.)
illiWeb .. illiGallery .. illiMuseum ... illiStaff
In this shared effort, all three involve taking an electronic image from a
third party rtica and displaying it inside a collection, on the Web, in an
advanced CAVEshell, and in print medium (cibachrome print mounted in model
case or on wall.) Since in each case there will be some documentation,
the web form is them most extensible, the museum the most static and the
gallery the most abbreviated.