Game Development Reference
In this multidisciplinary diagram 5 , we have clarified the concepts of immersion and
interaction. In the perspective of designing a VR device, instead of trying to reproduce
reality as completely as possible, we are interested in optimising the functional I 2
related to the application by analysing and deducing the cognitive and sensorimotor
I 2 to the optimum. It is this innovative approach that we are going to explain (Fuchs
et al., 1999).
The sensorimotor and cognitive I 2 are interdependent;
This basically means that functional I 2 are to be determined. They can be evident
in some cases, but in some cases they need to be studied precisely with the client of
the application. As in other situations of designing, the client often gives a vague
idea of what he wants. It is thus necessary to collectively analyse the planned
solutions in terms of sensorimotor and cognitive I 2 thoroughly and independently .
We have validated this approach in various professional applications;
A fourth level of immersion and interaction can also be introduced for applications
where multiple users operate together (collaborative work, VR teleconference): the
level of social immersion and interaction.
2.4.2 Virtual behavioural primitives
We will now explain what we mean by “Virtual Behavioural Primitives'' (VBPs). When
a subject is in a virtual environment, he has to perform one or more activities. These
activities can be divided into elementary activities, sensorimotor activities and cognitive
activities, which we call the VBPs. After careful consideration, we found that these can
be grouped under four categories in the virtual environment:
Observing the virtual world;
Moving in the virtual world;
Acting on the virtual world and
Communicating with others or with the application.
In the first category (observation), the subject is almost always “technically'' passive
in the virtual environment, though we know that human perception is not a passive
activity and is often connected to a motor activity like the ocular movement of the eyes
observing a screen. The subject is “technically'' passive in the sense where he does not
use the hardware device to search the sensory information in the virtual environment:
very few applications use, for example, an eye tracker to determine the motor activity
during eye movements. Tactile observation of a virtual object is rarely done using a
touch-sensitive interface and an interface that detects the movement of the user's hand.
In the other three categories, the subject is always active in the virtual environment:
he interacts with the environment. To help him perform these three VBPs of interaction,
5 We can associate the following with each box: Physician (for BI), neurophysiologist (senses
and motor responses), computer expert (software programs), psychologist (mental processes)
and ergonomics expert (desired perception and motoricity).