Game Development Reference
Properties of colour, light or transparency can be used for emphasizing certain
elements. For example, reference points can be highlighted using one characteristic
colour. The use of variable light sources can help the observer in his movements.
Primarily, significant lighting of communication channels in contrast to poor lighting
of impenetrable zones makes it possible to help the observer in his choice of movements.
Numerous other software aids can be incorporated into virtual environments,
depending on the characteristic of tasks to be done. These aids can be visual, but may
also use other sensory channels like hearing or smell.
The cognitive process of wayfinding can come into play during movements in a virtual
world. This process can be subconscious during simple or known movements. On the
other hand, this process may involve a significant cognitive load during more complex
movements. It is thus essential to take an interest in wayfinding for improving the
performances of users during their movement tasks in a virtual environment.
Wayfinding is often harder in a virtual environment than in a real environment,
because the technological constraints related to the virtual world make a good percep-
tion of the environment difficult. Thus, considerable effort should be taken to avoid
disorientation of the observers. On the one hand, copying the real world permits
observers to refer to experiences or situations which they have already gone through.
On the other hand, using options of the virtual world lets observers benefit from
software aids used for decision-making during their movements. Taking different ele-
ments from this chapter into account should help in improving the performances of
users when they need to move in virtual environments.
This chapter deals with movement techniques, i.e. actions performed by the user to
move within a virtual space. The main problem involves specifying any virtual move-
ment without physical movement or with an often restricted physical movement. It
is also necessary to note that movement done in the virtual world can be more com-
plex than its equivalent in the real world, due to, among other things, the absence of
gravity that permits any 3D movements. The hardware (hardware interface, virtual
environment, space available) can limit the techniques used. A technique based on a
movement of legs cannot be suggested to a seated user. Just as a technique using a
mouse cannot be suggested to a standing user who does not have a working platform
at his disposal.
It should not be forgotten that the feeling of movement in humans is provided
mainly by the visual system and the vestibular system (see chapter 3 of this treatise).
In other words, the receptive senses for walking are the proprioceptive sensors of
legs, tactile receptors in the soles of the feet, vision and the vestibular system for the
kinaesthetic sense. We can easily give the impression of movement by simulating the
view: This is the phenomenon of vection, which is the basic principle of animation in