Spatial Perception in Virtual Environments:
Evaluating an Architectural Application.

By Daniel Henry

A thesis submitted in partial fulfillment the requirements for the degree of


                   Master of Science in Engineering

                       University of Washington

                                  1992




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Master's Thesis


In presenting this thesis in partial fulfillment of the requirements for
a Master's degree at the University of Washington, I agree that the Library
shall make its copies freely available for inspection.  I further agree that
extensive copying of this thesis is allowable only for scholarly purposes,
consistent with "fair use" as prescribed in the U.S. Copyright Law.  Any other
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PREFACE


Over the last several years, professionals from many different fields
have come to the Human Interface Technology Laboratory (H.I.T.L) to discover
and learn about virtual environments.  In general, they are impressed by their
experiences and express the tremendous potential the tool has in their
respective fields.  But the potentials are always projected far in the future,
and the tool remains just a concept.  This is justifiable because the quality
of the visual experience is so much less than what people are used to seeing;
high definition television, breathtaking special cinematographic effects and
photorealistic computer renderings.  Instead, the models in virtual
environments are very simple looking; they are made of small spaces, filled
with simple or abstract looking objects of little color distinctions as seen
through displays of noticeably low resolution and at an update rate which
leaves much to be desired.  

Clearly, for most applications, the requirements of precision have not been met
yet with virtual interfaces as they exist today.  However, there are a few
domains where the relatively low level of the technology could be perfectly
appropriate.  In general, these are applications which require that the
information be presented in symbolic or representational form.  Having studied
architecture, I knew that there are moments during the early part of the design
process when conceptual decisions are made which require precisely the simple
and representative nature available in existing virtual environments.  

This was a marvelous discovery for me because I had found a viable use for
virtual environments which could be immediately beneficial to architecture, my
shared area of interest.  It would be further beneficial to architecture in
that the virtual interface equipment I would be evaluating at the H.I.T.L.
happens to be relatively less expensive and more practical than other
configurations such as the "Walkthrough" at the University of North Carolina.
The set-up at the H.I.T.L. could be easily introduced into architectural firms
because it takes up very little physical room (150 square feet) and it does not
require expensive and space taking hardware devices (such as the treadmill
device for simulating walking). 

Now that the potential for using virtual environments in this architectural
application is clear, it becomes important to verify that this tool succeeds in
accurately representing space as intended.  The purpose of this study is to
verify that the perception of spaces is the same, in both simulated and real
environment.  It is hoped that the findings of this study will guide and
accelerate the process by which the technology makes its way into the field of
architecture.



Acknowledgments


I would like to express my sincere appreciation to my committee members, Dr.
Tom Furness, Chairman, Technical Communication Professor Judy Ramey and
Architecture Professor Bob Sasanoff.  I would also like to extend my special
thanks to H.I.T.Lab collaborator Marc Cygnus for his design of the interactive
and rendering software, U.C.B Environmental Psychology Professor Kenneth Craik
for his support in Environmental Perception, Human Factors Professor Woodrow
Barfield and Dr. Brian Epps for their support in the design of experiment, and
Karen Jones for her superb editing.

I want to thank the Henry Art Gallery and their entire staff for their input
during the process and for their generosity in letting me use their gallery
spaces for this study.  Similarly, I would like to thank the professional
designers, the graduate students in architecture and the architecture faculty
for their participation.  Their involvement in the development of virtual
interfaces is an important condition for making sure that the tool will be
beneficial to their professional community.

I would also like to thank all of the H.I.T.Lab staff and students and the
numerous architecture students and faculty who were so generous in their
support at various stages of this study.  

And finally, I want to thank the one person who was most supportive and patient
during this process, ma très chère épouse Sabine.


INTRODUCTION


What makes virtual environments distinct from all other human-computer
interfaces is that the human being has the illusion of being completely
surrounded by spatial information.  In these computer generated environments,
the human being becomes a participant.  The illusion is sufficiently compelling
for participants to develop a sense of actually being present within the
synthesized space.  It makes the interpretation of the information and
interaction with the environment particularly easy because it requires the same
spatial perceptual skills as does the interpretation of real environments.

While there are many potential applications which could benefit from being
presented in these environments, the simulation of architectural spaces is
perhaps the most obvious one.  Is satisfies a real need in the architectural
community, that of improving the communication between the designer who relies
on architectural representations, and the client whose best understanding of
the design occurs only when being physically present within the space.

Designers' existing forms of spatial representation require intellectual
abstraction and offer only limited views.  Perspective renderings are fixed and
pre-determine our choice of views.  Models are three dimensional but they
cannot be entered.  Computer animations are dynamic but, as the path is
pre-determined, they also restrict our views.  In virtual environments,
participants are free to look, move and see most closely to the way they would
in the real environment.  Virtual interfaces become the ultimate perspective
drawing, the ultimate model, the ultimate computer animation for describing an
architecture project.

But while simulations can be very effective in representing spaces, their
misperception can result in erroneous judgments.  Participants who misperceive
the simulated space would probably be unhappily surprised at the outcome of the
project.  The entire process of discovering and evaluating a space with this
simulation could be detrimental to its intent of improving the communication
between the designer and the client.  

It is therefore imperative we address these basic questions:  just how well
does this new tool represent architectural spaces?  How valuable can our
judgments of virtual spaces be in predicting our judgments of real spaces?
Where are the weaknesses and strengths of this simulation tool?

The purpose of this study is to explore and determine the accuracy of virtual
interfaces in simulating the basic characteristics of architectural spaces and
to evaluate to what extent our perceptions of virtual and real spaces coincide.
Hopefully, this study will help explain the nature of the differences, if any,
in the perceptions of virtual and real spaces.  These results will, for the
design community, guide them in their use of this technology by highlighting
its existing shortfalls and strengths.  To the hardware and software
developers, the same results will indicate which aspects of the technology need
improvement most urgently.