Table Of ContentVirtual Reality Systems
edited by
R . A . Earnshaw
University of Leeds, UK
M.A. Gigante
Royal Melbourne Institute of Technology, Australia
H . Jones
Middlesex University, UK
A C A D E M I C PRESS
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Foreword
Few developments in computer-related technologies have caused as much excitement
in the general press as 'virtual reality'. In newspapers, in magazines, on television,
everyone seems to be talking about this 'fantastic new technology', even if they're
vague on precisely what it is. Even among the experts, the definitions vary. Here's
one definition: a VR system is one that gives the user an experience of being
'immersed' in a synthesized environment. This definition would, of course, include
the most common VR systems, those that use head-mounted displays. It would also
include professional night simulators, but probably would not include flight simulator
programs on home computers. It's unfortunate that we call this field 'Virtual Reality',
for the term can easily be misunderstood.
The simulations in current VR systems are far from reality and there's not much
chance that they're going to get even close to reality in the foreseeable future. The
term is reminiscent of 'electronic brain' for computer, naive and misleading at best,
certainly irritating, and it invites hype from the general press. How about virtual
environments or simulated environments? They don't have the sizzle, the MTV
appeal, but then neither does 'computer'. I'm afraid, for better or for worse, we're
stuck with 'virtual reality' as the name, at least for the general public.
It's important to know that VR didn't just come into being in the last few years.
Many experts trace the beginning of VR to Ivan Sutherland's 1965 IFIP address,
'The ultimate display' and to the description of a prototype VR system in his 1968
paper, Ά head-mounted three-dimensional display'. Although digital flight simulators
became widely utilized for pilot training in the 1970s, VR research was rather sparse
until the late 1980s, by which time the needed technologies - real-time image
generation, head-mounted display devices, and head tracking - became commercially
available at affordable prices. This availability, plus a number of very capable
promoters ignited the current craze. Not only is VR widely popular in research and
in the press, but some predict that VR will become available widely to everyone in
the not-so-distant future. Dr James Clark, Chairman of Sihcon Graphics Computer
Systems Inc., a leading supplier of 3D graphics-oriented workstations, in his ACM
Siggraph '92 invited talk, predicted that soon the home 'telecomputer' (television
plus computer) will have the power and functionality of 'VR graphics', and such a
telecomputer will enable a whole new range of applications to be engaged in by the
ordinary user.
With the fantastic possibilities and the promise of widescale availability, it should
be no suφrise that the media are in love with VR, occasionally seeming to promise
more than the more conservative technical specialists would think is prudent. Papers
such as the ones collected here are major influences in restricting the hype and in
promoting the 'reality' in virtual reahty,
'Systems' in the title and theme of the book is especially appropriate. For VR to
be effective, a systems approach is essential - it is futile to develop more powerful
χ Foreword
graphics image generation systems without an appropriate display device (and the
current colour LCDs in helmets leave much to be desired); it's difficult to walk
about a simulated house without an effective way to walk (pointing a glove and
'flying' leave much to be desired). It's not clear how much of a force VR will be
in the technological landscape of the future.
If the VR community of developers works hard (and is lucky), much of the
fantastic vision and promise of VR may become a reality in the next two decades.
If so, we'll look back on these years as the exciting pioneering era, just as we now
look back on the first years of today's major technologies - the radio, the telephone,
television, and the computer. And we'll bore our grandchildren with tales of how
primitive our systems used to be, how we couldn't move more than a step or two
in our virtual environments without losing head tracking, how we couldn't see much
in the helmets because the pixels were the size of boulders. If we're not lucky, we'll
be like the developers of failed technologies - probably forgotten. Of course we
could have a middle ground - 50 years ago, some people predicted that by now
we'd have a hehcopter in every garage. They thought that flying through the air
would be a much better way to commute than using roads. Despite the failure, so
far, of that prediction, helicopters are enormously important to humankind in many
roles, particularly search and rescue. Another example is space travel. In the 1960s
there was much talk about travel to the moon soon being like international air
travel. There's not much talk of that now.
Much of the excitement of this field may lie in the uncertainty about the future.
We don't know which of the dreams of VR will be realized. As my colleague Gary
Bishop says, 'it's not a done deal'. Today we can't even get a virtual cube to stand
still in front of us - it swims and lags behind our head and body movements due
to delays in tracking, image generation and displays subsystems. This 'swimming'
irritates and gives headaches to users and destroys the experience of being in a
virtual environment. It's not at all clear how easily we'll be able to overcome this
and related system problems. It's ironic that after spending years trying to get
objects to move rapidly we now find that it's harder to keep them still.
However this field develops, this volume will be valuable. It not only teaches us
much about the current state of the art in VR systems, but it will serve, in future
years, as a marker for where we were this year.
May we live long enough to be able to talk about these as 'the good old days' of
VR.
Henry Fuchs
Federico Gil Professor of Computer Science
University of North Carolina at Chapel Hill
North Carolina
About the Editors
Dr Rae A. Earnshaw, University of Leeds, UK
Rae Earnshaw is Head of Computer Graphics at the University of Leeds. He has
been a Visiting Professor at Illinois Institute of Technology, Chicago, USA,
Northwestern Polytechnical University, China, and George Washington University,
Washington, DC, USA. He was a Director of the NATO Advanced Study Institute
on 'Fundamental Algorithms for Computer Graphics' held in Italy in 1985, a Co-
Chair of the BCS/ACM International Summer Institute on 'State of the Art in
Computer Graphics' held in Scotland in 1986, and a Director of the NATO Advanced
Study Institute on 'Theoretical Foundations of Computer Graphics and CAD' held
in Italy in 1987. He is a member of the ACM, IEEE, CGS, EG, and a Fellow of
the British Computer Society.
Dr Earnshaw chairs the Scientific Visualization Group at the University of Leeds,
is a member of the Editorial Board of The Visual Computer, Vice-President of the
Computer Graphics Society, and Chair of the British Computer Society Computer
Graphics and Displays Group.
His interests are in graphics algorithms, human-eomputer interface issues, scientific
visualization, graphics standards, fifth generation graphics software, workstations
and display technology, mathematics of computer graphics, CAD/CAM, graphics
system building, and education issues.
Dr Earnshaw has authored and edited 15 books on graphics algorithms, computer
graphics, and associated topics, and published a number of papers in these areas.
Michael Gigante, Royal Melbourne Institute of Technology, Australia
Michael Gigante is the founder and director of the Advanced Computer Graphics
Centre at the Royal Melbourne Institute of Technology. He was previously a
research engineer in the Department of Mechanical and Production Engineering at
RMIT (1985-89). From 1982 to 1985 he was a design engineer at the Government
Aircraft Factories where he designed and implemented software tools for the design
and analysis of conventional and composite aircraft structures.
Michael Gigante received a BE from the University of Sydney and a BSc from
the University of Melbourne. He is a member of ACM and the IEEE. He has
served as a committee member of the Victoria branch of the Royal Aeronautical
Society of the Australasian Computer Graphics Association, acted as adviser and
consultant to both government and industrial organizations, and served as Technical
xii About the Editors
Program Chair of the International Conferences Ausgraph 88 and Ausgraph 90. He
is a member of the editorial board of Computers and Education, an international
journal published by Butterworth-Heinemann Ltd.
His research interests include image synthesis, virtual reality and real-time
interaction techniques, spatial data structures, and computer graphics in education.
Huw Jones, Middlesex University, UK
Huw Jones was brought up in South Wales and graduated from University College
Swansea with a BSc in Applied Mathematics in 1966. The following year he obtained
a Diploma in Education from the same institution and, after a short period as a
school teacher, has spent the rest of his working life as a lecturer in higher education
in London. During this period, he obtained an MSc in statistics from BruneI
University, became a Fellow of the Royal Statistical Society, a member of the
European Society for Computer Graphics and of the British Computer Society,
currently being vice-chair of that society's Computer Graphics and Displays Group
Committee. He is currently a Principal Lecturer in Computer Graphics and
Human-Computer Interaction in the School of Mathematics, Statistics and Computing
at Middlesex University, where he follows his research interest in fractal geometry,
and is head of the MSc in Computer Graphics and the BSc in Human-Computer
Interaction Design courses. He is married to Judy, a Mathematics teacher, and has
a son, Rhodri, and a daughter, Ceri.
Addresses of Editors
Dr R. A. Earnshaw
Head of Graphics
University of Leeds
Leeds LS2 9JT
United Kingdom
(Email:
Contributors
Klaus Böhm, ZGDV - Zentrum für Graphische Datenverarbeitung, Wilhelminen-
strasse 7, D-6100 Darmstadt, Germany
(E-mail: {boehm}@zgdvda.uucp)
D. A. Butler, Advanced Interfaces Group, Department of Computer Science,
University of Manchester, Oxford Road, Manchester Ml3 9PL, UK
Kim Michael Fairchild, Institute of Systems Science, National University of
Singapore, Heng Mui Keng Terrace, Kent Ridge, Singapore 0511
(E-mail: [fair]@iss.nus.sg)
Martin Friedmann, Vision and Modeling Group, The Media Laboratory, Massachu
setts Institute of Technology, Cambridge, MA 02139, USA
(E-mail: {martin} @media-lab.media.mit.edu)
Charles Grimsdale, Managing Director, DIVISION Ltd., 19 Apex Court Woodlands,
Almondsbury, Bristol BS12 4JT, UK.
Lee Beng Hai, Institute of Systems Science, National University of Singapore, Heng
Mui Keng Terrace, Kent Ridge, Singapore 0511
(E-mail: [benghai]@iss.nus.sg)
Ng Hern, Institute of Systems Science, National University of Singapore, Heng Mui
Keng Terrace, Kent Ridge, Singapore 0511
(E-mail: [nghern]@iss.nus.sg)
T. L. J. Howard, Advanced Interfaces Group, Department of Computer Science,
University of Manchester, Oxford Road, Manchester M13 9PL, UK
R. J. Hubbold, Advanced Interfaces Group, Department of Computer Science,
University of Manchester, Oxford Road, Manchester M13 9PL, UK
R. S. Kalawsky, Systems Technology R & D , British Aerospace pic, Brough, North
Humberside, HU15 lEQ, UK
Ang Tin Leong, Institute of Systems Science, National University of Singapore,
Heng Mui Keng Terrace, Kent Ridge, Singapore 0511
George L. Mallen, System Simulation Ltd, 250M Bedford Chambers, Covent Garden,
London WC2E 8HA, UK
xiv Contributors
Craig McNaughton, Advanced Computer Graphics Centre, Royal Melbourne
Institute of Technology, 723 Swanston Street, Melbourne 3053, Austraha
A. D. Murta, Advanced Interfaces Group, Department of Computer Science,
University of Manchester, Oxford Road, Manchester M13 9PL, UK
Michael J. Papper, Advanced Computer Graphics Centre, Royal Melbourne Institute
of Technology, 723 Swanston Street, Melbourne 3053, Austraha
Alex Pentland, Vision and Modeling Group, The Media Laboratory, Massachusetts
Institute of Technology, Cambridge, MA 02139, USA
(E-mail: {sandy}@media-lab.media.mit.edu)
P. Quarendon, IBM UK Scientific Centre, St. Clement Street, Winchester S023 9DR,
UK
(E-mail: Internet
Contributors xv
John Vince, Rediffusion Simulation Ltd, Crawley, W. Sussex, RHIO 2JY, UK
A. J. West, Advanced Interfaces Group, Department of Computer Science,
University of Manchester, Oxford Road, Manchester M13 9PL, UK
(E-mail:
Acknowledgements
Many people have supplied information on their uses and applications of virtual
reality systems. Many designers and implementors have supplied details of their
systems, and also illustrations. Others have supphed details of aspects of virtual
reality, as well as slides. We express our thanks and appreciation to all those who
have contributed.
The Bibliography is an extended version of a reference list for virtual reahty in
the public domain. It is reproduced in its extended form with due acknowledgement
to all those who contributed information to earlier versions.
This is to be included in the on-hne bibhography stored at the sei.virtual-worlds
archive site (milton.u.washington.edu). This bibhography has been built by a number
of people who have volunteered their time and effort, and is in the public domain.
Some companies were unable to supply information or illustrations of their
products, despite being invited to do so. They have therefore been omitted from
the information on current vendor systems. The list of vendor systems does not
therefore claim to cover all the systems in the market place at the time of writing.
Disclaimer
The views expressed by the contributors of information on products is believed to
be accurate and given in good faith. However, authors and publisher do not hold
themselves responsible for the views expressed in this volume in connection with
vendor products or public domain products. In addition, the authors and publisher
do not hold themselves responsible for the accuracy or otherwise of data extracted
from vendor specifications.
Copyright Material
Some slides are reproduced by permission of their originators and these are noted
in the text. Some materials are reproduced by permission of other publishers and
societies. In particular those by Professor R. S. Kalawsky are reproduced by kind
permission of Addison-Wesley Ltd, and those by W. Robinett and J. P. Rolland by
kind permission of the Society of Photo-Optical Instrumentation Engineers (SPIE).
Material by Professor M. Friedman et al is reproduced by kind permission of the
Association for Computing Machinery (ACM).
Cover Illustrations
The images on the cover come from the chapters by T. W. Rowley, M. Friedmann
et al, and D. Thalmann. They are reproduced with legends in the colour plate
section.
