Options and Futures
In common Virtual Reality systems, a drawn 3-D view of a model world is
changed in accordance with the movements of a human user in the
real world; if the user turns his or her head, the view shifts;
if the user moves a real hand, a drawing of a virtual hand moves
But how does a VR system know where its user's hand is?
There are many possible approaches to this; one that is frequently
employed in commercial system is the Polhemus.
A Polhemus tracker is a small cube - one or two inches in height - that
to a heavier ``base station'' with thin cables. The movements of the
cube in an electromagnetic field that the base station emits can be
sensed and transmitted to a computer in some way.
Once the position of the cube is known, it can be used to
control anything: commonly a position of a virtual
object or of the camera, but just as well the pitch of a sound,
or the hue of a color.
The system I have in mind consists of
one or two motion trackers (the lighter and less obtrusive, the better),
an audio output device, and
a game console with some exchangeable storage medium,
like those used for home videogames. In the
console is a small computer than can execute programs on
For this small, portable platform, different applications
can be bought:
- Musical instruments.
(Think Laurie Anderson rather than Nigel Kennedy.)
The user can ``pick up'' kinds of sounds by moving the trackers
in and out of a certain space; after that, pitch and amplitude
are modulated in the remainder of the space.
As a next step, the cartridge is replaced by a cable connecting
the system to a PC; the PC runs a development system on which
different ``instruments'' can be designed and programmed using a
visual programming language.
- A training system for Tai Chi, or at least a system that accompanies
these moves by appropriately soothing New Age music; or more
``aerobic'' systems where, for example, the speed of the music
adapts to the speed of the person exercising.
- A one-player motion puzzle.
The object of the game is to advance through a database of
The player advances by making the ``right'' motions with the
The game gives hints as to which motions it wants the player
to make by making certain sounds, or by modulating base sounds
in a certain way; and it gives feedback about the actual
Kudos to the Very Nervous System and related work by David Rokeby for
teaching me that even inexperienced users can make interesting sounds.