Virtual reality: an overview of User-related Design Issues: Revised Paper for Special Issue on...

Editorial

Virtual reality: an overview of User-related Design IssuesRevised Paper for Special Issue on “Virtual reality:

User Issues” in Interacting With Computers,May 1998

Stella Millsa,* , Jan Noyesb

aCheltenham and Gloucester CHE, Faculty of Business and Social Studies, PO Box 220, The Park,Cheltenham GL50 2QF, UK

bUniversity of Bristol, Department of Experimental Psychology, 8 Woodland Road, Bristol BS8 1TN, UK

Abstract

Within the last couple of decades, Virtual Reality (VR) has emerged from its early beginnings insimulators, and is now a realistic option in a number of applications, the range and number of whichare increasing annually. It has also been heralded as the new future interface for allowing humans tocommunicate with computers. Hence, given the continuing developments and rapid advances in thisarea, it is timely to produce a Special Issue in Interacting With Computers focusing on the user issuesrelating to the successful employment of this technology.q 1999 Elsevier Science B.V. All rightsreserved.

Keywords:Virtual Reality; Virtual environments; Human–computer interaction; Usability; Applications

1. Introduction

Virtual Reality (VR) has recently become a familiar and ubiquitous name for the area ofcomputing which takes the user into a synthetic environment. This is primarily becausefalling computer costs combined with increasing processing power have made VR moreaccessible through PC (personal computer) based systems. Taking a literal interpretationof the term VR, it is actually a contradiction in terms but has attracted much discussion;indeed VR has been referred to as an oxymoron [1]. It is for this reason that someresearchers prefer to use the expression ‘virtual environments’ (VEs) since this gives amore accurate and less contradictory description of the situation [2]. However, it is arguedin [3] that VE should be restricted to situations where a person perceives that they areeither within or interacting with a virtual environment. Whichever term is used, and it has

Interacting with Computers 11 (1999) 375–386

0953-5438/99/$ - see front matterq 1999 Elsevier Science B.V. All rights reserved.PII: S0953-5438(98)00057-5

* Corresponding author. Tel.:1 44-1242-543231; fax:1 44-1242-543205.E-mail address:[email protected] (S. Mills)

become common practice to use both phrases almost interchangeably, VR/VEs are three-dimensional, computer generated, simulated environments that occur in real-time asmanipulated by the user [4,5]. Therefore, this technology is primarily concerned withallowing individuals to experience a synthetic form of reality1.

VR technology has been applied in a number of application areas, including medicine,education and the entertainment industry. It also has obvious benefits in the area oftraining, especially in safety-critical situations where it is not feasible due to the risksinvolved to allow novice trainees to have contact with the actual environment. Anotherarea, rapidly becoming popular, is that of networked VR worlds. The World Wide Webalready has more than 400 worlds accessible through three-dimensional visualisers andthese have led naturally to multi-user environments. It is important here to make thedistinction between true multi-user synthetic environments and those associated withvisual links such as video-conferencing. The difference is rapidly becoming blurred insome cases but the distinction continues to be made between those worlds linked byinformation flowing between screens, such as is found in video-conferencing, and thosesynthetic worlds which allow multi-user access to manipulate the objects within that worldsimultaneously. However, despite the many benefits of VR technology and its applicabil-ity to a variety of application areas, there is still a considerable amount of work neededbefore its use becomes more widespread [6]. Much of this work concerns the humanfactors issues [7]. For example, the demands made on the technology in terms of providingappropriate navigation, orientation and feedback for the user have only just begun to beaddressed (see research on gaze direction in [8]). In addition, the ability of the interfacedesign to convey the naturalness of the real world is important. In this respect, anothertechnical problem is obtaining sufficient texture without increasing the file size beyond thereaches of most computers, especially personal computers.

The multi-modal aspects of VR interactions also need to be considered. One of thefeatures of interacting with VR technology is being able to present the user with multipleinputs and outputs [9] such as speech and video, as found in some systems using ‘augmen-ted reality’2. It is thought that this multi-modal aspect in virtual worlds may result inenhanced human performance and some studies have already indicated this (see [11]). Aswith all systems’ design, the primary concern is to ensure that the design of the interfacemeets the needs of the user population to allow quality interactions free from frustrationand irritation. At the moment, we have a limited understanding of how to present multipleinputs and outputs in VR in a form that users can readily accommodate. Examples of someof the difficulties were outlined in [9]:

1. the need for redundancy when interacting with the system, e.g. designing the system sothat different input forms can be used to carry out the same task, thus providing abackup should one input prove problematic;

2. the extent to which users can manage parallel inputs, e.g. carrying out a direct manip-ulation task at the same time as issuing voice commands (see [12]);

S. Mills, J. Noyes / Interacting with Computers 11 (1999) 375–386376

1 Note: for ease of reading, the term ‘VR’ will be used throughout this paper.2 Augmented reality ‘can be thought of as the “middle ground” between VE (completely synthetic) and

telepresence (completely real)’ ([10], p.2). This is a more precise definition than those used previously by thecommunity.

3. the need to ensure that tasks are carried out by the most appropriate mode of input, e.g.finding out which task is best achieved by voice, direct manipulation, gesture, etc.

These are some of the immediate problems that are being addressed; this papercontinues by drawing attention to other factors that are important for the user in thedevelopment of VR technology.

2. Development of VR/VE

It is an interesting point to note that virtual worlds have long existed in the form ofbooks of fiction; classical authors exhibited skilfully the ability of immersing the reader ina virtual environment. This environment, however, was specific to each individual readeras each character in the book would have some differing qualities for whoever was readingabout them. In computing terms, VR removes these subtle differences so that each world isno longer totally reliant on the user’s imagination but has a real and interactive environ-ment. Thus, the early beginnings of VR can be seen in simulators and even in head-mounted displays of interfaces as used in military applications. However, some simulatorsdo not usually allow the user to move around within the world; e.g. in a ship’s bridgesimulation the views from the windows change but the user may not move around thebridge as s/he is usually positioned statically. However, advanced simulators can comeclose to being examples of ‘non-immersive’ VR, that allow the user of such a system stillto be aware of influences outside in the visual world. In contrast, ‘total immersion’ refersto the situation in which the user is completely immersed in the virtual environment and isremoved from influences emanating from outside that virtual world. This usually requiresthe wearing of a headset and will include some interactive devices such as gloves and/ortracking mice. Thus, there are essentially two types of virtual environment available to thecomputer user: non-immersive and totally immersive. Table 1 summarises the main attri-butes of a virtual environment that essentially involves three-dimensional objects movingin a three-dimensional world in real-time. Intuition, freedom and a feeling of presence aredesirable user attributes. However, their development still needs further work in order tocover satisfactorily the needs of users. Indeed, it may be argued that a ‘feeling of presence’will never be achieved in non-immersive worlds since the user, by definition, is ‘outside’the world, and some would argue that this attribute is not more easily implemented in an

S. Mills, J. Noyes / Interacting with Computers 11 (1999) 375–386 377

Table 1Attributes of a virtual environment [13]

1. Computer-generated simulated environment, experienced as three-dimensional by the participant.2. Objects in the VE are themselves three-dimensional, with orientations and locations independent of theparticipant’s viewpoint.3. Objects are assigned some ‘intelligence’ or features, e.g. gravity and friction.4. Participants interact in real-time with the environment and objects.5. Environments are recreated ‘continuously’ in real-time according to the participant’s behaviour.6. Interaction is as intuitive as possible through a variety of sensory channels.7. Freedom and support are provided for participants to navigate around the VE.8. Feelings of presence and involvement are generated for participants in the VE.

immersive world. However, while each environment does have some different designissues for the user, there are some generic issues that apply to both types of environment.

3. Generic design issues for VR

As with all modes of human–computer interaction, there are a number of human factorsissues associated with working in a synthetic environment [14], and these can be dividedbroadly into two groups: those which relate to the human and those which follow from thetechnology. In the former group, we might consider visual and perceptual attributes of thehuman as well as health, social and educational implications of using this technology.With regard to the technology, an important difference between VR and other computer-based applications is that the user has the ability to ‘move around’ objects totally so thatthe back of an object can be viewed in the same way as the front. Although there are noproblems with generating this all-round viewing technically, the resulting technology cancause problems of orientation within the world for the user. This is primarily because inthe real world, the user moves around the object to be viewed. In a synthetic world this isnot possible and so the object has to move in such a way as to give the user the illusion thats/he is moving around the object. This returns to being a technical problem in terms ofinadequate lifelike animation that still causes problems in the user domain [15]. Of course,most computer interactions result in the user moving objects, e.g. mouse actions control-ling the cursor, or objects moving, e.g. text generation on a screen, but the differencewithin a three-dimensional environment is that the movements have to be in three-dimen-sions too. This means that six degrees of freedom are required instead of the more usualfour. Non-immersive VR systems can achieve these extra degrees of freedom by using athree-dimensional mouse (often referred to as a ‘spacemouse’), although most allowconventional keyboard–mouse input. However, this also brings operating problems forthe user. Immersive VR systems generally utilise a helmet and glove but these too canhave similar operating problems, even if the user physically moves. Thus the probleminter-linking the technology and user domain is that of technically achieving a natural wayof moving around the world without the user moving his/her body physically. Thisrequires the user to learn a new way of viewing objects which in turn requires learningnew operational skills for using the interactive devices.

Another generic problem is that of texturing and shadowing in order to ensure imageslook lifelike enough. Fortunately, the human has excellent capabilities of ‘filling in detail’so that ‘stick-men’, for example, are easily recognisable. The actual load on the computerprocessor in generating just one three-dimensional human is usually very considerable andconsequently, slows processing time, which is a problem in its own right. In some applica-tions, particularly those in immersive VR, photographs are now used for textures but againprocessing times for generating a large graphic file can become intolerable for the user. Inthis case, the large size of files generally can cause storage problems that can generate slowresponse times as the processor searches for, and then generates, certain files. Thisproblem is reiterated for audio files that must play in real-time. Thus, the processingtime for the generation of sound must be very small, if it is not to be perceived as adelay by the user. This is particularly important in immersive systems as the user is not so


aware of the computer system and any delay in synchronisation can cause disorientationfor them. Hence, the interface must be ‘invisible’ in the sense of being unobtrusive [16].

Shadowing is generally easier in a non-immersive environment since the user know-ingly views the images on a display and consequently the image does not have to havesuch a precise shadow. It can be seen again that it is the user’s perceptual skills that carrysome of the processing load. In immersive systems, the images need to be much morelifelike, so that the user should not be aware of being in a computer-generated world. Theissues for the user arising out of these technical problems are concerned with visualperception and cognitive load, as the users, at least at present, have to supplement visualdetails or tolerate long processing times. Some designers (e.g. [2]) would contest the viewthat users should not know they are in a virtual world; they feel that the user should alwaysknow that s/he is in a synthetic world.

Another problem of a generic nature is that of ‘help’ for the user. Traditionally incomputer-based systems, this has been a manual that may be available in hardcopy oron-line. However, it follows that in a VR world the user should be able to move aroundfreely or else the analogy with the real world is seriously diminished. It is not usual to finddialogue boxes in the real world; help here usually comes from a book or another personbut little work has been done to ascertain the most natural and acceptable way to providehelp in VR. Indeed, some VR development shells only give the facility of dialogue boxes[17] and while these may be acceptable for non-immersive VR, they are certainly intrusiveand unnatural for immersive systems. Experimentation with more lifelike help systems,such as reaching for a book or talking to another person, is needed. In this area, the work in[18] is commendable in that a wizard was employed when the user appeared to need help.

It is worth noting, however, that while not a strictly human factors’ issue, no designmethod has yet been developed for VR systems. In general, software design (excludingVR) often follows a methodology such as structured systems analysis and designmethodology (SSADM) or Yourdon, but no such structured method exists for VR systems.Most VR systems development follows a storyboarding and prototyping approach butwith few guidelines for screen design. The resulting system can lack purpose and, atthe very least, the user requirements will not be verified or modelled. It will be sometime before most VR systems will follow a SSADM type methodology or even a con-textual design method that attempts to verify the system design and model the systemrequirements [19].

As a first, and important, step towards this goal, Kaur et al. in this Special Issue havedeveloped a model for interaction with VR systems based on the concept of a task–actionmodel. This work is specifically relevant to the user’s interaction with the system andmodels the interaction of users as they explore a VR world. This paper begins by proposinga number of theoretical models of interaction with virtual environments; three of these areevaluated through user studies, namely, the task action model, the explore navigate modeland the system initiative model. It was found that users utilised certain actions much morethan others and this allowed a picture to develop of the ways in which users view andinteract with a VR world, e.g. some stages in the interaction were missed out altogetherwhile there was some backtracking to previous stages. It is concluded that these findingscan be used in order to refine the theoretical models used to inform interface designguidelines for VR.


While all these points are relevant to both immersive and non-immersive VR systems,we now turn to those issues that are particularly pertinent to one type or the other.

4. Specific design issues of non-immersive environments

This is the most popular of the two types of virtual world since the software can be runon a desktop often using a conventional mouse and trackball [20]. However, the softwaremust be capable of producing realistic images that can be moved in six degrees of freedomthus allowing the user to move around the world including moving behind objects.Consequently, the employment of interactive devices, such as spacemice which extendtheir freedom from four to six degrees, are often used. These three-dimensionaldevices are not easy to learn in that it can take several days for a user to feel incontrol when moving around a world [15]. One of the reasons for this has alreadybeen stated and includes the fact that in order to view behind an object the userdoes not physically move in a non-immersive world whereas they would in a real world.This, in turn, means that the user has to visualise the necessary movement by way of theinteractive device in order to turn the object so that it has the apparent movement ofremaining stationary while the user ‘moves’. It is this new approach to ‘pointing’ thattakes some users considerable time to learn. Also associated with the motion of objects onthe screen are problems associated with parallax [2]. These and other technical deficien-cies can produce symptoms of visual inaccuracy including the misjudgement of distances[14] as well as visual strain [21].

Consequently, the first issue for users of non-immersive VR is usually associated withthe use of three-dimensional interactive devices. In order to overcome this, some devel-opers design systems that still use the conventional mouse in combination with somekey(s). For example, the spacebar is a favourite for toggling between the differentmodes. Not only does this require the use of both hands, it can raise other problems ofco-ordination (e.g. non-expert users do not use the mouse at the same time as keying on astandard QWERTY keyboard). However, its main advantage is that it overcomes the costof purchasing three-dimensional devices.

The other main issue of particular relevance to non-immersive VR users is that ofperceiving textures and depth. Many non-immersive systems are run on relatively lowspecification PCs that simply do not have the processing power or storage requirements toallow realistic textures. Again, this implies an increase in cognitive load for the user thatmay not become apparent until some interactive time has elapsed [17]. This has beenshown to result in the user gradually becoming frustrated as s/he struggles to supply themissing cues [2].

5. Specific design issues of immersive environments

In this environment, the user is required to wear a headset in order to remove influencesfrom the real world and to become totally immersed in the synthetic world. Inter-action with the world is through gloves and other handheld devices such as space-mice. As costs of equipment fall, there will be an increase in the use of these types


of environment for training, medical therapy and games. However, serious problemsstill remain with the user undergoing orientation and motion sickness symptoms [22]as well as psychological disturbance when the user returns from the synthetic worldto the real environment [23]. Perceptive difficulties also arise, and the effect of these on thecapabilities of the user has yet to be conclusively analysed. As with non-immersiveenvironments, evaluation needs to be undertaken of the information learnt from totalimmersion in environments, as well as the long-term effects of moving between virtualand real environments.

Another less documented issue arising from the use of totally immersive systems is thepsychological effect on a user of being observed in this synthetic environment by indivi-duals in the real world. For example, a video we use often induces amusement fromviewers as the users of an immersive VR system move around apparently purposelesslyclad in helmets and clutching a haptic device. This is primarily because the video viewersare unable to see the VR world of the system users. Some users feel this is an intrusion oftheir privacy particularly when the use of immersive systems is required by theiremployer. Other social and ethical issues, raised in the papers presented here, will needattentive care if they are to be satisfactorily solved. As with any developing technology,new and unforeseen problems can arise especially where time must elapse before the fulleffect is known. Consequently, it is impossible, at present, to be specific about the densityand impact of some of these social and psychological problems and with time they maybecome less significant as, for example, an increase in intrusion into personal privacy maybecome more generally acceptable.

A third design issue is concerned with the health and safety aspects of using immersiveVR. In [9], a number of direct effects that occur at a microscopic level are outlined,e.g. at the level of individual tissues. These can be categorised according to theireffects on (i) the visual system, e.g. eyestrain and flicker vertigo; (ii) the auditorysystem, e.g. noise induced hearing loss; (iii) the body having to make repetitivemovements, e.g. tenosynovitis; (iv) phobias, e.g. claustrophobia and anxiety. Sick-ness and physical disorientation arising from using VR systems has been well docu-mented. Cybersickness, as it is often called, can occur as a result of users beingexposed to VR. This may take the form of the sensation of the head spinning and/ordelayed onset of nausea and sickness. However, just as there is no cure for (ordinary)motion sickness, so the strategy for avoiding cybersickness is proving elusive. Indeed, theafter effects of immersive VR can be considerable, lasting for several days, unlike vehiclemotion sickness that usually quickly subsides once the individual leaves the vehicle. Inaddition, just as some people do not suffer from motion sickness, so users have varyingdegrees of discomfort during and after using immersive VR.

There is little doubt that it will be some time before all the design issues associated withimmersive VR can be assimilated as a comprehensive list. The technology is still in itsinfancy and technical developments are being made continuously so it is possible thatsome of these problems will be avoided rather than solved. It is also likely that new oneswill also arise as take-up of the technology increases and the user population widens[24]. Meanwhile, in addition to the generic issues associated with motion sickness anddisorientation, the psychological problems of the user switching from real to syntheticworlds remain the primary issues for human factors specialists.


6. Domain applications

One of the most popular uses of both non-immersive and immersive VR is in the contextof training, particularly in application areas that are difficult to realise in the real world.Some examples include the use of VR in fire prevention training, aircraft maintenance andthe efficiency of evacuation procedures in sinking ships [18]. Since most of these criticalsituations arise in an industrial setting, it is not surprising that research in this area is oftenundertaken within the relevant industry, e.g. the emergency services, automotive andprocess control industries, and healthcare trusts. However, as yet few studies have beendevoted to the evaluation of such training that has previously been undertaken in theclassroom and is now taking place in a pseudo-environment of which the users werewell aware.

VR systems have also been used for system modelling, particularly in engineeringapplications such as car design. A similar application is that of house or office design inwhich, for example, prospective purchasers can view a new house or a kitchen before anyphysical alteration is started. In both cases, the three-dimensionality of VR is exploitedtogether with real-time movement. So it is possible through building the VR world to scaleto check if a saucepan, for example, will fit in a particular cupboard or whether the driverof a vehicle can easily reach the audio-cassette player whilst driving. These applicationsare often built in non-immersive VR for two reasons: first, one of cost, and secondly,because viewing a non-immersive world requires no wearing of apparel which could beseen as intrusive on the client–vendor relationship.

Applications for medical therapy have been developed, but again the evaluation of thesesystems (with the exception of the work with phobics) has been minimal and this iscertainly an area in which much work needs to be carried out. Another medical applicationis that of practising surgery where the student can use a scalpel and due to the force-feedback that VR offers can learn the right amount of pressure needed for invasive surgery.This work is also discussed in the paper of Krapichler et al. in this Special Issue. In thispaper, Krapichler et al. consider the application of multi-modal, user-oriented human–computer interaction within the context of medical image analysis. Image segmentation isan important but laborious step in computer aided analyses and processing of tomogra-phical data, and VR has many benefits to offer. The paper demonstrates these advantagesby considering the two examples of bronchoscopy and angioscopy in a virtual environ-ment. Here, the VR environment and tools accelerate image segmentation when comparedto conventional interactive approaches.

Computer systems have often been considered as a tool for assisting the user in complet-ing a specific task. In the case of VR systems, the task is usually less specific in that theuser may be learning something or modelling a situation. Following this generality ofapplication rather than specific task, there have been suggestions (e.g. [21,25]) that theremay be a certain learning style (see [26]), and hence a more definable set of users who areparticularly at ease with VR. The work in [27] and Mills and Arau´jo (in this Special Issue)have attempted to evaluate the learning experience. Even though both studies confirm thatwhile subjective feelings such as enjoyment rate highly, the actual learning process is notconsidered so favourably; however, more studies are needed in this area before moredefinitive conclusions can be drawn. Indeed, in [27] it is asserted that the constructivist


approach to learning is best suited to the visualisation attribute of VR. This in turn will suitthose users who are exploratory in learning rather than those who prefer the more system-atic and structured design of Instructional Systems Design [28]. Mills and Arau´jo in thisSpecial Issue built a small system that exploited the visual aspects of VR, thus taking aconstructivist approach. The system was used by final year Portuguese undergraduates andthe resulting learning was evaluated using a performance test. In general, the studentsscored lower marks than a similar peer group taught by more traditional methods with alecturer, although there was no significant difference in the results. Indeed, it may be thatlearning styles/preferences may be the cause of the lower marks even though the studentswere given the choice of learning traditionally or by using the VR system. The results doconfirm those in [27] which suggest that while enjoyment rates high in VR, learning ismore problematic. Consequently, one issue which needs to be addressed is that of the beststyle of learning that is supported by VR systems which in turn will give some guidance asto whether there is a type of person who will best profit from learning through VR. Ofcourse, this illustrates the need for sound theory on which the use of VR systems can bebased.

As interactive environments progress, the use of multi-user VR will increase and thiswill raise the issue of how the users interact with each other while using the environment.As worlds are created within the VR system rather than remaining static, the nature ofcollaboration and designing within that collaboration will need to be assessed. Issues ofmodality and the integration of visual, tactile and acoustical information will need to beaddressed. One of the exciting, if not daunting, attributes of VR is that there is no soundtheory base for users’ reactions in these situations simply because they have not arisenbefore, so the nature of expansion of VR becomes exploratory in itself. This leads natu-rally to the next issue — the evaluation of VR systems and the learning that results fromtheir use.

First of all, it is worth recalling that we know of no design principles specifically derivedfor VR systems. This is probably not surprising given the newness of the area. However,VR may actually call for a flouting of conventional guidelines such as those associatedwith the use of colour. For example, it is often suggested that colour on the screen shouldbe used conservatively as too many colours clutter up the display, thus increasing searchtimes [29,30]. However, in real life we often view a large number of colours, and hence,there is a need for VR graphics to resemble the real world. Indeed, if VR is to emulate areal lifelike world, then in most cases, different and varying shades of colours will be usedin abundance. In a similar way, it may be difficult to use the common methods of systemsevaluation such as heuristic analyses [31] and usability questionnaires and measures (e.g.SUMI [software usability measurement inventory], [32]). As Mills and Arau´jo (in thisSpecial Issue) point out, there is a need for a more pertinent instrument for assessing theusability of VR systems as well as specific heuristics that have been tried and tested andthat will yield some data for validation of the system. In addition, evaluation must takeplace that assesses the learning experience for different types of user as well as theusefulness of modelling designs. Since no one has evaluated the suitability of differentmethods for VR, an exploratory approach to evaluation must be used initially in order tobuild a theory that can be used in future systems. In this sense, the work of Conkarand Kimble in this Special Issue, takes an exploratory approach in order to develop an


evaluative framework for VR systems. This model is a first, and important, step towardsverifying the design of a VR environment through evaluation. The paper attempts to developa generic model which is independent of a specific VR application and such work is to beapplauded as it can be seen as a method of evaluation specifically for VR systems. Theframework is called CLIMATE (Community, Language, Interaction, and Medium in theAnalysis of Telepresence Environments) and the paper describes its development throughthe use of log transcripts, participant observation and questionnaire surveys. The authorsintend that CLIMATE should be viewed as a step further towards integrating social andtechnical design requirements in the application of computer-mediated communication.

While all these applications will mature given time, there will be, no doubt, new areas ofapplication that will exploit the three-dimensional real-time animation giving the lifelikevisualisation that VR offers.

7. Future directions

VR has attracted much media and academic interest, but the reception has been mixed.As pointed out in [3] perhaps we need to consider why we need VR at all. Certainly, therehas been a degree of scepticism among the scientific community as to the usefulness ofVR. This has been reinforced by the high costs of good quality VR technology with thecapabilities needed for research purposes. In this context, the development of arcade-typegames is important for the future development of VR in that it mass produces many of thedevices which will be used later for industrial systems. Thus the games market results incheaper technology that is more easily available, as well as engendering a familiarity withVR concepts by a sector of the population who may not otherwise come into contact withleading-edge technology.

There is little doubt that the use of virtual environments for training will increase asthese are the only media available for lifelike simulation of safety critical situations andmuch will be learnt from the evaluation of the experiences of users of these systems. Aswith the games application area, the quality of the virtual environment will improve to beextended into practical applications in other areas such as secondary school education. Inaddition, evaluation of the learning process of these users will indicate the real value ofusing synthetic environments as instructors in comparison to teaching aids that are supple-mented with traditional classroom-teaching.

Already progress has been made using the World Wide Web for conferencing, e.g. theCybErgconferences; this aspect of VR is likely to become increasingly used as interactivecommunal virtual environments develop technologically and become more sociallyacceptable. The development of communal synthetic environments can only enhancesocial contact and interaction. Inevitably, there will be an increase in certain areas thatare morally unacceptable to certain sections of society. For example, VR systems alreadyexist which allow users to create the perfect woman and to titillate the creation for sexualstimulation. While this may not be legally pornographic, it raises the issue of whether thereis a need for ethical guidelines when developing VR. Of course, this area is fraught witharguments and counter-arguments but is one that is ripe for discussion since developerswanting to remain in business will inevitably produce what can be most readily sold.


The future is also likely to see the development of augmented reality - a mix of VR andreality which “allows the user to see the real world, with virtual objects superimposedupon or composited with the real world” [10]. The difference between VR and AR is thatin VR, whether immersive or non-immersive, the environment is totally synthetic while inAR, reality and virtual are combined in a way so that ideally the user in not aware of thedifferent state of each object. This is achieved by using graphics to create synthetic objectswhile the real world is projected on to the user’s viewing area by either using video or asee-through head mounted display [10]. Already applications are being used in medicineand engineering although there are problems associated with AR which are similar to thoseof VR such as the system’s functioning in real-time without a time-lag and there is nodoubt that the solving of technical problems in VR will inform the solutions for AR.However, it is possible that new problems, peculiar to AR, will arise as this aspect isdeveloped.

8. Conclusion

Virtual reality is a new technology although some would argue that it is a new term forexisting technology. Whichever term is adopted however, VR is still in the early stages ofdevelopment. In [33] it is suggested that all new technological developments movethrough an incunabular phase, where older forms of the technology will continue toexist although they may not be suited to the newer medium. This may well be the currentposition we have reached with VR. As pointed out in [9], p. 31 “many users of virtualenvironments don their high tech helmet and gloves and enter the virtual world only to findfloating menus awaiting them!” There are a number of user issues arising from the use ofVR systems, and these have been outlined here. The most important of these pertain toboth immersive and non-immersive VR and both types of VR will benefit from theirimprovement. Problems specifically associated with either type of VR have also beendiscussed, although some of these are described in greater detail in the papers that follow.

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