VIRTUAL REALITY
Silvano de Gennaro
CERN
Related Subjects:
Forget the "demon-cyborg" myth that fiction Media built around the catchy expression
"Virtual Reality". What movies, and sometimes reporters too, show about VR is as close
to reality as the Time Travel Machine is to Particle Physics. Virtual Reality is nothing more
than a new communication interface between man and machine, which in fact humanises
further the link between us and our data.
The paradigm keyboard-screen is reversed, and we are placed at the centre of our data,
immersed in the virtual environment that we created in the computer. We can move around
and explore it from the inside, interacting with the objects that we see in the most natural
way, with the same movements of our body that we use in the real world.
Rather than causing our alienation in a cybernetic nightmare, Virtual Reality brings our
digital data within our sensorial sphere, so that we can understand them and "feel" them
better.
Visualisation
For over a decade biologists, chemists, meteorologists, geologists and scientists from
almost all fields (with the exception of Particle Physics), have been using synthetic imaging
to better visualise and understand complex phenomena, controlled by n-dimensional
equations, which are often impossible to plot mentally. This kind of scientific visualisation
used to be produced off-line by supercomputers, in the form of short movie clips, some of
which have been presented at SIGGRAPH.
With the growth of graphic power of some
mainframes and workstations, it became possible to produce this kind of animations in real
time, therefore being able to interact with them. The real revolution came in the late
eighties, with the introduction of immersive peripherals, such as display helmets and
gloves. These tools allowed the observer to navigate in the virtual environment and grab
objects or control equation parameters with his/her own hands, using a metaphoric
representation closer to human understanding than dialog boxes, numbers and Greek
letters. To express this natural feeling of exploration and interaction, Jaron Lanier, founder
of VPL Inc., coined the term "Virtual Reality".
Virtual Prototyping
Virtual Prototyping is the application of Virtual Reality to Engineering. Architecture and
Engineering are probably the most straightforward application domain for VR. This is
because of three main reasons:
- their environments are geometric and mechanical, involving no animal or vegetal parts
and functions, therefore they are easy to represent in a computer.
- a CAD model is usually built anyway,. during the conception phase
- physical prototypes represent a real problem, as they are expensive, unprecise, slow to
build and most of all, they are usually impossible to modify along with design changes.
This last point in particular has drawn the attention of large research labs and industry, to
VR as a new effective technology to build prototypes. The results were astonishing. From
NASA's "Virtual Windtunnel" [1], used to verify the Space Shuttle's aerodynamics, to the
latest Boeing 777, entirely prototyped in VR, manufacturers claimed to have enormously
reduced the design-prototyping loop. According to the French manufacturer Renault, the
design lapse for a new car has dropped from six months to three weeks with the advent of
Virtual Reality. At the same time, because of the increased visibility of details in the CAD
model, due mainly to the usage of stereovision and immersion, more design errors were
found at an earlier stage, reducing the cost of fixes at a later time.
Distributed Design
Another important aspect of Virtual Prototypes is that they can be made available on
networks and distributed across several design partners, allowing a visual integration of the
engineering design in wide area collaborations. The advent of the World-Wide-Web and
VRML [2] has contributed to improve the human interface and ease of access of these
models on Internet. Through a 3D-browser engineers located anywhere can navigate and
point-click on objects of the model, to obtain detailed information, drawing, diagrams and
pictures. These Web browsers not only act as a graphic index to the engineering database,
but they also allow instant, on screen integration of the prototype, by loading each part of
the assembly from a different site. Simultaneous changes are immediately published and
reflected onto the networked model.
Networked Virtual Prototyping is revolutionising all aspects of communication and
technical integration of large engineering projects.
VR at CERN
The VENUS (Virtual Environment Navigation in the Underground Sites) project at CERN
applies VR technology to improve Scientific and Engineering Visualisation methods linked
to Particle Physics, and in particular to the design, construction and maintenance aspects of
the LHC (large Hadron Collider) project. A complete description of the VENUS project
and of its 3D Web Browser, "i3D", can be found in [3], [4], [5].
References:
- S. Bryson and C. Levit - "The Virtual Windtunnel: an Environment for the Exploration
of Three-Dimensional Unsteady Fluid Flows". Proceedings of IEEE Visualisation '91,
San Diego, Ca. 1991.
- J.R. Vacca - "The Outer Limits - Virtual Reality on the Internet". Internet World,
volume 6, number 3, March 1995.
- S. de Gennaro - "Virtual Prototyping at CERN". Proceedings CHEP'95, Rio de
Janeiro, Brazil, 1995.
- S. de Gennaro - "A Web Browser for LHC Design Integration". Proceedings
CHEP'95, Rio de Janeiro, Brazil, 1995.
- J.-F. Balaguer and E. Gobbetti - "i3D, a High Speed 3D Web Browser". Proceedings
VRML'95, San Diego, Ca., 1995.