Kees van den Berg's

Hi I'm Kees van den Bergh. I work in the User Centred Engineering
(UCE) group of the Service Development & Support division of KPN
Research, The Netherlands. KPN Research is the Research institute of
the Royal PTT Netherlands NV.

VEs are computer generated worlds through which the user can "walk".
In a Shared Virtual Environment (SVE), several people can be present
at the same time and they can communicate with each other.

My interest is mainly in 3D-shared virtual environments. I'm not
interested in technical issues about building SVEs, but in the
communication aspect of these SVEs.
By the communication aspect I 'd like to find out how the concept of
telepresence can be used to substitute 'regular user interfaces'.

I'd like to present a set of commonly shared characteristics of shared
virtual enviroments. These "telepresence elements" are believed to be
responsible for the telepresence experienced in the reviewed
SVEs. Among these are:

1) A spatial lay-out of the environment
2) Freedom of movement
3) Responsiveness
4) Real world control

Issue: "Can the concept of telepresence be used as an alternative
approach to telecommunication systems for residential users, in such a
way that the technological and emotional thresholds of domestic
network access tools and services are lowered"

An elaboration to the telepresence elements is added below.

1. Spatial lay-out of the environment

Design the environment in such a way that the user can construct a
mental map of it. Use magical 'transporters' only if they add extra
functionality to the scene. This can be the case if large distances
must be crossed to get somewhere. Design the scenes in such a way
that the user can discriminate between them. When a user is in a
room, the walls shouldn't be exactly the same on each side. Doors,
button and links can be made the same in each scene to help identify
them. Create depth in a scene by applying image textures (if the
software allows it) or by object textures (grids of lines or small
dots, for instance). Objects that shift in front of each other
(motion parallax) create an illusion of depth.

2. Freedom of movement

When possible, use collision detection. When this function is not available,
design the scenes in such a way that users don't have to manoeuvre through
tight spaces. Keeping up speed (framerate) in the scene is critical. Allow
people to explore the environment in all necessary dimensions. Adjust the
travelling speed to the environment: slow when indoor and fast outside.
Don't make buildings and rooms where nothing is inside, because people will
want to enter everything they see and they will be disappointed when there's
nothing to be seen.

3. Responsivess

Provide feedback for every choice the user makes. Feedback can be auditory
(clicking of a button) and visual (change of colour of the button). Advanced
systems can even provide other feedback in the form of touch and force. The
environment can respond in various ways to the user:

By greeting him when he approaches
- By changing the sound of footsteps when the surface changes from stones to
- By making a sound or changing the colour of the wall when a user bumps
into something
- By turning on lights when the user approaches
- By automatically opening doors when the user approaches

As a general rule, responding objects and interaction make the VE appealing,
so make sure that the user can interact with (all) the objects in the scene.

4. Real world control

Real world control on a high level can be achieved by mimicking everyday
interaction. Examples are: opening doors, putting stuff in bags, driving a
car. These clichs can be used in VEs based on standard metaphors. If the
scene is abstract, clichs aren't available and real world control must be
based on certain conventions about the way things work. Such conventions can
be based on physics (when you squeeze something it becomes smaller) and on
learning (turning a dial to the right results in a linear increase). The
science of control ergonomics can provide some insight into these concepts.
Indirect interaction via pop up menus might be replaced by more natural and
direct equivalents in a VE.