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Exploiting Virtual Reality Techniques in Education and Training: Technological Issues

4. Developments in VR Technology (cont)

4.2 Functional Characterisation of a VR System

There is a tendency to think of head mounted displays when considering VR systems. Unfortunately, this narrow perspective leads to confusion when people talk of other forms of VR system. The solution is to use the term ‘VR’ as an all embracing term to cover all forms of VR system and to use other terms to describe the different approaches. To add further confusion some people use the term virtual environments instead of VR. However, it is better to think of a virtual environment as a computer representation of a synthetic world. This means a virtual environment can be defined irrespective of the delivery technology. If we take the broadest possible definition then it is feasible to characterise any VR system in a consistent manner. It is important to take a systems perspective of a VR system in its entirety and include the components that help construct the environment, refer to Figure 2. The jagged edges of the ellipses bounding the components in the diagram illustrate that there is poor integration between the component parts. It is not sufficient to just produce a virtual environment alone - there is a need to control the component parts of the environment in way that makes the user believe that they are actually immersed in a real environment. Therefore, it is necessary to provide some form of simulation that interacts with the virtual environment.

Figure 2 Systems Perspective of a Generic VR System

Neglecting the issues of system performance for the moment, the peripheral technologies define the different forms of VR system. For example, the term ‘desk-top VR’ has emerged which does not relate so much to the virtual environment but instead refers to the delivery technology used. Since a desk-top VR system is generally based on a PC platform there is a tendency to assume that a desk-top system offers inferior performance. This is not quite true since it is perfectly feasible to employ the very best graphics systems for a desk-top VR system. However, it is better not to think of the performance of the underlying technology at this stage because this will be dictated by the application.

If a generic VR system is defined as shown in Appendix A then it becomes possible to provide a consistent description for all VR systems. This approach is significantly clearer when it comes to determining which form of VR system to use for a particular application.

Refering to the diagram given in Appendix A, the most fundamental feature of any VR system is that it representsa human computer interface comprising:

Expanding these features: