Homestead Hilevel Bridge
Truss structures are a type of building that is ubiquitous in
the industrialized world. Common examples include railroad
ridges, radio towers, roof supports, and building exoskeletons.
However, these structures are sufficiently complex that modeling
them by hand is time consuming and tedious. In this project,
I developed a method for designing truss structures automatically
using non-linear optimization. To do this, I represent trusses
as a set of rigid bars connected by pin joints, which may change
location during optimization. By including the location of the
joints as well as the strength of individual beams in the design
variables, we can simultaneously optimize the geometry and the
mass of structures, and generate realistic, physicaly stable models
of truss structures.
This work was presented at SIGGRAPH 2002.
SIGGRAPH 2002 paper: PDF (2926 Kb)
The fracture of brittle objects, such as glass or ceramics, is a
complex phenomonon to model realistically. Even fairly simple
geometris, such as a pane of glass, when broken can result in
hundreds of irregularly shaped shards. Further, people have a
fairly good visual intuition on how brittle objects should
break, which makes the task of modeling this phenomonon even
harder. For this project, which I undertook in my second years
of graduate school, I developed a method for the rapid and
controllable simulation of the shattering of brittle objects
under impact. I represented the objects to be shattered as a set
of point masses connected by distance-preserving linear
constraints. This use of constraints, rather than stiff springs,
yeilds a significant advantage in speed while still retaining
fine control over the fracturing behavior. The forces exerted by
these constraints during impact are computed using Lagrange
multipliers. These constraint forces are then used to determine
when and where the object will break, and to calculate the
velocities of the newly created fragments.
This work was first presented at Graphics Interface 2000, and republished in Computer Graphics Forum.
GI 2000 paper: PDF (2893 Kb)
Traces explores the aesthetics of physical presence in
telecommunication processes in networked CAVEs. A CAVE is a four-sided
stereo display system creating the illusion of immersion within a
computer generated virtual environment. Traces is concerned with the
development of intuitive interfaces involving whole the body and its
movements. The focus is spatialbodily interaction between distant
participants via real-time 3D image and sound traces. As more of our
social and cultural lives occur in wider bandwidth online settings,
questions arise about embodiment, virtuality and the possibility to
'be' in two locations at once. Traces gives users direct experience of
having a dispersed body. The user interacts with the dynamics and
volumes of simulated bodies, but they are translucent and
ephemeral. In Traces, the user's body acts as a three dimensional
brush. Traces is an outstanding CAVE application as it defines the
virtual space as a comnunication space rather than a geometric one,
emphasing on the state of being networked.
This work was first presented at Ars Electronica, 1999.
Simon Penny's web page about this work
International Conference on Artificial Reality and Tele-existence, 1999 paper: HTML
Convergence (The Journal of Research into New Media Technologies) paper: PDF (266 Kb)