Observers call it magic. Writers say it's Alice's
wonderland. Engineers refer to it as science. The popular term for the
imaginary world that looks, sounds and feels real is "virtual
reality." Virtual reality is a phenomena with a lot of promise and
a lot of technological difficulties that have to be solved,"
It's a technology that I think is best looked at as a
new medium, in the same way that film and television was a new medium at
one time. It took 50 years from when the motion picture projector was
patented in 1891 until techniques and technology had improved to the
point where a film like 'Citizen Kane' could be made.
Virtual Reality is generally a Computer Generated
(CG) environment that makes the user think that he/she is in the real
environment. One may also experience a virtual reality by simply
imagining it, like Alice in Wonderland.
The virtual world is hosted on a computer in the form
of a database (e.g. terrain database or environment database). The
database resides in the memory of the computer. The database generally
consists of points in space (vertices), as well as textures (images).
Vertices may be connected to form planes, commonly referred to as
polygons. Each polygon consists of at least three vertices. The polygon
could have a specific color, and the color could be shaded, or the
polygon could have a texture pasted onto it. Virtual objects will
consist of polygons. A virtual object will have a position (x, y, z), an
orientation (yaw, pitch, roll) as well as attributes (e.g. gravity or
The virtual world is rendered with a computer.
Rendering involves the process of calculating the scene that must be
displayed (on a flat plane) for a virtual camera view, from a specific
point, at a specific orientation and with a specific field of view (FOV).
In the past the central processing unit (CPU) of the computer was mainly
used for rendering (so-called software rendering). Lately we have
graphics processing units (GPUs) that render the virtual world to a
display screen (so-called hardware rendering). The GPUs are normally
situated on graphics accelerator cards, but may also be situated
directly on the motherboard of the computer. Hardware rendering is
generally much faster than software rendering.
Objects in the virtual world may be manipulated by
means of a Data Glove. A data glove measures the flexure (bend) of the
user's fingers. The user may grab a virtual object and put it at a
different spot. The user may also throw the object. The position (x, y,
z) and orientation (yaw, pitch, roll) of the user's hand is measured
with a 6 DOF tracker. If it is a force-feedback data glove, the user
will also be able to deform the virtual object, and feel the object
(e.g. a tennis ball) resisting the deformation.
In order to navigate (e.g. walk or fly) in the
virtual world, a Space Controller is used. The space controller could be
a normal joystick, or a computer mouse. For example, when the mouse is
moved forward, the user moves forward in the virtual world, when it is
moved to the left, the user moves to the left, etc. Force-feedback
joysticks or mice could provide hap tic cues to the user, e.g. when the
user moves into a virtual wall. Normal joysticks and computer mice are
usually used in Desktop VR Systems. In Immerse VR Systems we normally
use baseless joysticks as space controllers. This enables the user to
leave the desktop and to interact with the virtual world while standing
It is also possible for different users to share the
same virtual world. This is normally achieved by connecting the host
computers to a computer network. Each user's host computer broadcasts
the position and orientation of the user in the virtual world. The users
may therefore 'see' each other in the virtual world. In fact, users will
see representations, referred to as avatars, of each other in the
virtual world. They will be able to interact; working together or
competing. The sharing of virtual worlds is generally referred to as
'shared virtual worlds', or as 'networked virtual reality'.
Sight and hearing are the main human senses currently
used to experience virtual worlds. Touch (as in tactile- and
force-feedback) is becoming more commonplace. Smell dispensers are
entering the marketplace, enabling the user to smell the virtual world
as well. Taste dispensers will follow soon.
VR is ideal for the training of operators that
perform tasks in dangerous or hazardous environments. The trainee may
practice the procedure in virtual reality first, before graduating to
reality-based training. The trainee may be exposed to life-threatening
scenarios, under a safe and controlled environment. Examples of
dangerous or hazardous environments may be found in the following
Aviation, Automotive, Chemical, Defense, High
Voltage, Industrial, Marine, Medical, Mining and Nuclear Energy