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Collaborative Visualization: New Advances in Documenting
Virtual Reality with Igrams
The
following paper was published in the IEEE Proceedings
for Information Visualization 1999; presented at IV
'99 on July 15, 1999 at the Univeristy of London, ISBN:
0-7695-0210-5, IEEE Computer Society Order Number PR00210
Ellen
Sandor, Janine Fron, Kristine Greiber, Fernando Orellana
and Stephan Meyers, (art)n, and Dana Plepys, Margaret
Dolinsky, and Mohammed Dastagir Ali, Electronic Visualization
Laboratory, University of Illinois at Chicago.
Abstract
(art)n
and the Electronic Visualization Laboratory (EVL) at
the University of Illinois at Chicago have collaborated
on the development of the first real-time, stereoscopic
hardcopy output of virtual reality applications - the
ImmersaGram (IGram). The results of this new technology
directly address a broad range of information visualization
issues along a wide spectrum of disciplines from art,
architecture, and science, to medicine, engineering
and education.
Keywords:
Virtual Reality, Art, Science, lenticular, PHSCologram,
autostereography
1.
Introduction
How can virtual reality applications be documented and
shared outside the virtual environment without the use
of expensive computer hardware, access to limited resources,
simulators, etc.? What medium is available for artists/scientists
to record their work in-progress to contemplate, assess
and evolve without direct access to the virtual reality
system? Is there a way to extend one's artistic expression
beyond the virtual application itself? An underlying
answer to these and many other questions is the IGram
- a virtual reality snapshot.
Among
the more principal and critical concerns has been the
ability to capture a fleeting moment or state within
a virtual reality experience. Video and photographic
documentation of virtual reality participants and environments
has yielded only marginal results; the interactive nature
of the experience can be documented, though image quality
is significantly compromised due to resolution loss,
monoscopic display and difficult lighting circumstances.
High-resolution digital slides or photo-graphs can be
created, but do not record the stereoscopic nature of
the event, and cannot be generated in real-time. IGrams
address these problems by providing a low cost, real-time
method for printing three-dimensional virtual imagery
to an 8"x10" or 11"x14" stereo transparency.
Larger format 20"x24", and 20"x40"
medium priced IGrams are viable with a Hewlett Packard
Design Jet 2500CP. Other printing variations are optional
and currently being explored.
2.
Aesthetic background
IGrams are a direct outgrowth of (art)n's computer interleaving
process, known as PHSColograms. The results of computer
interleaving provide an archival three-dimensional photograph
from computer rendered content. PHSCologram is an acronym
for photography, holography, sculpture and computer
graphics. In search of new artistic paradigms, the PHSCologram
founding artists synthesized the arts of sculpture,
photography and computer visualization. PHSColograms
are made from a series of 10-65 (or more) snapshots
of a virtual environment that are photographed inside
of the computer. This series of frames is then combined
inside of the computer, output to film and viewed with
a barrier screen or lenticular lens [1]. PHSCologram
artistry traverses frontiers of science and medicine,
as well as educational and historical documentation
while remaining true to the fundamentals of fine aesthetics
and new technology.
(art)n's
body of work in PHSColograms created a unique dialogue
between photography and sculpture in computer graphics
and virtual reality [2]. The PHSCologram process draws
on earlier advances in photography, including daguerreotypes,
photogravures and gelatin silver prints. Rodin was among
the first sculptors to use photogravures to publish
his "Monument to Balzac" in the famous Camera
Work quarterly [3]. Brancusi and David Smith are also
known for using photography to document their works.
Brancusi's photographs show his vision of the artist
in the studio; Smith's photographs reveal the artist
in the landscape [4]. The documentation produced by
these artists are strong works in their own right. It
is (art)n's vision for IGrams to inspire a new aesthetic
consciousness in virtual environments that encourages
artists to explore photography and sculpture in their
own work.
3.
The IGram system
IGram development has addressed the desire to better
document virtual reality environments created for EVL's
CAVE(tm) virtual reality system [5]. The CAVE is a fully
immersive 10'x10'x10' cubic room, where stereo images
are projected onto three walls and the floor. A participant
wears LCD shutter glasses, equipped with a tracking
device to create the stereo effect and define the user's
location within the environment. A three-dimensional
'wand' is used to navigate and interact with virtual
objects within the space. IGrams are created within
the CAVE system - virtually - while exploring and manipulating
the three-dimensional space.
Any
'Performer-based' CAVE application can be used to capture
IGrams. The three-dimensional scene is ported to the
IGram utility and displayed in the CAVE, where the user
manipulates (translates, rotates and scales) the scene
within a virtual three-dimensional frame representative
of the IGram (hardcopy) output area. The 'depth-of-field'
is controlled by changing interleaving values/distances
with the 'wand', which affects the stereo perspective
projection. In this process, the CAVE itself is akin
to a virtual camera, the virtual frame in 3-space -
the camera's view-finder, and the wand - the lens/aperture
controls.
Interleaving
is the digital simulation of the photographic combing
procedure. (art)n's autostereo-graphic process is a
result of interleaved computer graphics based on the
concept of binocular disparity. Following the virtual
'positioning' of a digital setting, individual images
are captured at slightly different angles across the
scene in a straight line from left to right. Each of
the images is broken up into rows and columns of pixels.
(art)n's proprietary software combines these rows and
columns of pixels, and arranges them into a single image.
The image is output onto a piece of film or paper. The
result is a blurred image on transparency film. A barrier
screen is placed over this image to complete the 3-D
effect. In the case of IGram production, once virtual
"positioning" of the scene is complete, ten
individual images are captured, interleaved and displayed
full scale in the CAVE for technical and aesthetic evaluation
before committing to final hardcopy output. When cropping
and framing results are satisfactory, interleaved IGram
images are sent to the Epson Photo EX color inkjet printer
to transparency material and final processing.
4.
Experiences
Early on in the development cycle of the IGram CAVE
utility, virtual 'art' environments were selected as
the initial focus [6]. Capturing the virtual art experience
and extending the application beyond the walls of the
CAVE environment was an obvious choice. A creative and
aesthetically pleasing scene was selected for development,
in order to assess whether or not the IGram could capture
the essence of the virtual experience, preserve the
sense of immersion, and act as an extension of the original
artwork into the domain of virtual hardcopy.
Results of early experiments were somewhat enlightening.
Of concern was how to capture a vast space within a
limited frame. Since virtual space can be infinite,
objects within the scene can be located at great distances
from each other. The ability to quickly move from place
to place in virtual reality minimizes this distance,
yet in trying to document the scene in time, does not
necessarily yield visually appealing results. To address
the spatial considerations, it became obvious additional
control over the environment position and scale was
required. These features are inherent to the IGram program,
and are used to compose or select the most representative
portion of the virtual scene for archival. A sequence
or series of IGram 'snapshots', as in any 'photographic'
medium, most readily documents states in time, as well
as vast space not easily captured in a single image.
An
unexpected discovery was that the artist could use an
IGram as a creative development tool. Having an accessible
hardcopy to analyze the interrelationship of objects
and composition within a specific area of the scene
is incredibly beneficial. Access to the virtual display
environment can be limited to application review. Scenes
are developed in a simulator on the workstation, then
checked in the virtual display environment. Going back
and forth between writing code to displaying the results
can be somewhat disconcerting and indirect for the creative
process. The artist's ability to 'study' the scene with
some consistency and accessibility can be vastly improved
by using the IGram as a working 'sketch' from which
to develop and enhance the artwork when not at a workstation
or in the virtual system.
5.
Conclusion
The primary goal in developing the IGram hardcopy was
to archive the virtual environment, while creating a
derivative art form or document that can stand on its
own merit, tell a story or evoke an emotion. Clearly,
it was not developed strictly to document artistic and
creative virtual reality applications, but the wide
range of virtual reality application areas. In the case
of scientific, engineering or medical applications,
the IGram can reveal an important feature or aspect
of a data set. For architecture/design applications,
the IGram can be used for design review, client presentations,
as well as recording 'stages' in the production cycle.
As virtual reality applications evolve, the IGram will
continue to play an important role in preserving and
enhancing the exchange of information and recording
of technology across a diverse and expanding audience
base.
[1]
S. Meyers, E. Sandor and J. Fron, PHSColograms and Rotated
PHSColograms. Computers & Graphics 19.4 (July/August
1995): 513-522
[2]
M. Neal, More then Science, More than Art. Computer
Graphics & Applications. 8.6 (November 1988): 3-5
[3]
E. Steichen, Camera Work 34/35 (April/July 1922):7-11
[4]
Pachner, J. David Smith Photographs 1931-1965. San Francisco:
Fraenkel Gallery, New York: Matthew Marks Gallery &
San Francisco: Fraenkel Gallery, 1998
[5]
C. Cruz-Neira, D. J. Sandin, T. A.DeFanti, R. V. Kenyon,
and J. C. Hart, The CAVE: Audio Visual Experience Automatic
Virtual Environment, Communications of the ACM 35. 6
(June 1992): 65-72.
[6]
M. Dolinsky, Creating art through virtual environments,
Computer Graphics 31.4 (November 1997): 34-5
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