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Section 3: Virtual Reality Methods and Techniques#

3.3 User requirements #

Once a design specification and storyboard have been prepared for a virtual reality project, the next step is to think about how users will interact with the world and about their expectations from the world. Some of these considerations are discussed below.

3.3.1 Ease of use

The length of time that users are likely to be willing to invest to use a world generally reflects the length of time that they spend viewing it. For example, if a virtual world is displayed in a museum then users generally will use it once for a short period of time. If the world is intended for use at home or in a school or college, users will generally have more time to view it and may be willing to invest more time to learn how to use it. Consideration also has to be given to the complexity of the world and to the fact that certain types of users will have more advanced technical skills than others. This can change depending on where the model is accessed.

3.3.2 Conventions in navigation

Users may have preconceptions about how navigation or interaction with the world will work. These may be based on previous experience or on intuition. Developers need to make sure that the user interface follows standard conventions where these exist. For example, many people are familiar with Windows conventions to exit a program and some will also be familiar with the standard conventions used for navigation in a particular browser plug-in. Developers are recommended to adopt any existing conventions and try to make local conventions compatible in style so that they are easier for users to learn. Navigation should be obvious and intuitive so that users know how to get around the model easily and can return to the start or go back should they want to.

3.3.3 Realism

As more virtual worlds are seen in computer games and on the television, users have growing expectations about their level of realism. Developers need to consider what level of realism users will be satisfied with while at the same time not suggesting a level of certainty where none exists. Documentation should be kept when constructing the model so that at the end of the building process it is easy to tell which parts are based on evidence and which are works of imagination (see Section 5.1). This should be conveyed to the user in some way, perhaps through an explanation of how the model was built.

3.3.4 Degree of interaction and movement

The extent to which users wish to interact with virtual worlds varies with different audiences. Children may be bored if they can't interact while non computer-literate adults may be intimidated if they have to navigate by themselves. Pre-set animations and fly-throughs may be appropriate for one audience but not for another.

3.3.5 Method of interaction

Users can interact with virtual worlds by using a mouse, keyboard, joystick or a touch-sensitive screen. Different methods of interaction are appropriate for different situations. For example, a touch-screen offers a robust user interface suitable for a museum display. Users with disabilities may have very specific requirements for interacting with a virtual world. See the case study 'Exorcising the Flesh' by Kate Allen for an exploration of people's interactions with her Fine Arts VRML installations.

3.3.6 Speed

Users have different expectations about how quickly they should be able to move through a world or how long they will wait for a response. Ideally, users should have a sense of smooth movement and should not have to wait so long that they begin to doubt whether things are working properly. Speed of use is directly related to the hardware and software platforms being used to view the world. In some cases the speed of the network connection also needs to be taken into account.

3.3.7 Hardware and software

Different audiences may view your world from different hardware and software platforms. For example, home users are likely to access your world using a desk-top computer and a dial-up modem. Developers who are creating virtual worlds for home users may need to compromise between satisfying the user's expectations of the feel and visual quality of the model and file size (see Section 3.5).

Another important consideration which may influence the choice of development software is whether plug-ins are needed to use virtual worlds. Different audiences may be more or less willing to access and download a plug-in depending on the length of time that they anticipate using a world. For example, users of an educational world are probably more willing to invest time in such installations. Home users might be reluctant to install plug-ins and may prefer to use models that either do not require them or use operating systems that incorporate plug-ins as standard. Plug-ins may also be difficult to obtain, become obsolete or not work with future versions of the platform.

See Brancusi's Mademoiselle Pogany for a discussion of how user requirements influenced the delivery of the virtual reality in this project.

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