Theatre Design & Technology - Spring 1993 - 33

self in a New York aparrment, playing a
hand of poker wirh Oscar i\ladison and
Felix nger. To parrake in such a rhearre,
rhe audience need nor even leave home.
The furure may hold some kind of enrerrainmenr nerwork rhar people can access
ar home by plugging in rheir own VR
equlpmenr.
For rhose rhar enjoy a more communal experience, a virrual rhearre may urilize live or compurer-generared accors
inreracring wirh large projecrion screens.
Com purer-genera red scenery could
meramorphose on cues provided by rhe
accors. Purring an audience in a room
surrounded by such screens would provide an experience close co rhar of rhe
fabled "holodeck" of Srar Trek fame. In
facr, rhere already exisrs such a room.
"The Cave" is an experimemal VR sysrem in which visicors don special goggles
rhar provide 3-D simularion and are surrounded by various images such as a
compurer simularion of rhe ciry of
Chicago.
Virrual realiC)' is nor beyond rhe reach
of rhe average scenographer. Because
srare-of-rhe-arr sysrems can cosr rens of
rhousands of dollars and require a high
level of rechnical experrise, amareur VR
devorees have found ways co fabricare
rheir own less sophisricared yer effecrive
equipmenr. The sysrem I have creared ar
rhe Universiry of Kansas' Universiry
Thearre was creared from spare parrs and
scavenged componenrs from video
equipmenr and video games, and cosr less
rhan 5500. This "home-brew" vinual
realiry can be as convincing as more
expensive commercial versions for rhe
same reason rhar rhe rhearre is convincing in rhe illusions ir presenrs.
Borh virrual realiry and rhe rhearre
rely on our narural rendency co creare a
menral image of realiC)' from only a few
clues. Our perceprions of rhe world
around us are very incomplere bur our
brains have been condirioned co fill in
rhe missing pieces. This ralenr nor only
allows us co deal wi rh rhe demands of
everyday life, bur co make sense of essenrialy absrracr consrrucrions. For example,
we are able co see deprh in rwo-dimenrional painrings and decipher rhe images
on relevision.
This abiliC)' co complere fragmentary
perceprions is evidenr in rhe rhearre
when we creare a room wirh only rhree
walls and no ceiling, rurn all rhe furnirure co face rhe same direcrion, and call ir
realism. The classic play Our TowlI is rradirionally sraged wirh only a few sricks of
furnirure and a couple of srep ladders. In
all producrions, ro a grearer or lesser
degree, we ask ou r aud iences ro suspend

rheir disbelief and "go along" wirh rhe
illusion so long as ir is presenred in good
fairh. If rhe illusion is well presenred, rhe
audience will soon cease ro see ir as illusion and accepr ir as rhe currem version
of realiry. In virrual realiry rhe visiror is
asked co do rhe same. If rhe illusion creared wi rh a "home-brew" svsrem is less
derailed rhan rhose produced by a more
expensive one, ir merely requires rhe visiror ro go a lirrle furrher in accepring irs
version of real iC)'.
My own sysrem includes a homebrew HMO, made from rwo 2.7-inch
color LCD relevisions. The screen resolurion of such a sysrem is somewhar grainy
bur comparable co rhar of commercial
HMOs. lore sophisricared sysrems
would generare separare srereo images for
each eye in order ro render a convincing
3-D image. However, crearing rwo separare images slows compuring rime measurably and grearly increases rhe cosr of
rhe imerface. Forrunarely, a convincing
illusion can be creared by using rhe same
image for each eye, separaring rhem so
rhar rhe user's eyes focus in parallel lines.
The illusion of deprh can be enhanced in
rhe crearion of rhe virrual world by placing objecrs on a parrerned ground plane,
a raeric used frequenrly in com purer
games.
My sysrem does nor include a head
rracker as ir would require a more powerful com purer capable of processing informarion ar rhe speed necessary ro creare a
smoorh illusion. If rhere is a noriceable
lag berween movements of rhe user's head
and rhe corresponding change in rhe
view presented in rhe HMO, a sense of

disorientarion will occur, in some cases
severe enough ro cause morion sickness.
In a low-cosr svsrem, users are only
allowed ro look in rhe direcrion rhey are
rraveling. After rhe user acceprs rhis condirion wirhin rhis version of real i C)', rhe
lack of head movemenr seems naru;al.
lovemenr wirhin my virrual ser
designs is conrrolled by' a MarreIT,\1
Powerglove. This device was originally
designed for LIse wirh inrendo nt enrerrainmenr sysrems bur has proved ro be an
effecrive low-cosr alrernarive ro commercial VR gloves. Worn like an ordinary
glove, ir allows a user ro move rhrough
vinual spaces bv morioning wirh rhe
hand or fingers. The whole sysrem is
powered by an accelerared lacinrosh ™
LC running a 3-D interacrive modeling
program called Vinus HI Walkthrough,
al rho ugh si m ilar resul rs can be achieved
wirh a varieC)' of personal compurers and
inreracrive sofrware packages.
The overall effecr is rarher convincing. As users navigare rhe virrual scenery,
rhey begin co lean co rhe side as rhey go
around corners, lean back wirh unexpecred accelerarions, and duck rheir heads
under low vinual beams. Because users'
perceprions of where rhey are do nor
coincide wirh rheir acrual physical surroundings, I have rhem sir in a chair co
minimize rhe danger of falling over or
walking inro an unseen acrual rable. The
whole perceived experience rhen becomes
similar ro driving a mororized wheelchair
rhrough rhe virrual rhearre.
Afrer rhe user is seared, rhe HMO is
placed on rhe head and rhe glove slipped
over rhe righr hand. The simularion is

TD&T

1993 SPRING

Table of Contents for the Digital Edition of Theatre Design & Technology - Spring 1993