Authoring Edutainment Stories for Online Players (AESOP)

22 Pages·2016·1.56 MB·English

University of Pennsylvania
ScholarlyCommons
Departmental Papers (ESE) Department of Electrical & Systems Engineering
January 2007
Gameplay, Interactive Drama, and Training:
Authoring Edutainment Stories for Online Players
(AESOP)
Barry G. Silverman
University of Pennsylvania, [email protected]
Michael Johns
University of Pennsylvania
Ransom Weaver
University of Pennsylvania
Joshua Mosley
University of Pennsylvania
Follow this and additional works at:http://repository.upenn.edu/ese_papers
Recommended Citation
Barry G. Silverman, Michael Johns, Ransom Weaver, and Joshua Mosley, "Gameplay, Interactive Drama, and Training: Authoring
Edutainment Stories for Online Players (AESOP)", . January 2007.
Postprint version. Published inPresence: Teleoperators and Virtual Environments, Volume 16, Issue 1, February 2007, pages 65-83.
This paper is posted at ScholarlyCommons.http://repository.upenn.edu/ese_papers/317
For more information, please [email protected].
Gameplay, Interactive Drama, and Training: Authoring Edutainment
Stories for Online Players (AESOP)
Abstract
This paper describes initial efforts at providing some of the technological advances of the videogame genres in
a coherent, accessible format to teams of educators. By providing these capabilities inside an interactive drama
generator, we believe that the full potential of educational games may eventually be realized. Sections 1 and 2
postulate three goals for reaching that objective: a toolset for interactive drama authoring, ways to insulate
authors from game engines, and reusable digital casts to facilitate composability. Sections 3 and 4 present
progress on those tools and an in-depth case study that made use of the resulting toolset to create a large
interactive drama. We close with lessons learned to date and a look at the remaining challenges: the unpleasant
reality that state-of-the-art tools are not yet able to boost the productivity of edutainment authors.
Comments
Postprint version. Published inPresence: Teleoperators and Virtual Environments, Volume 16, Issue 1, February
2007, pages 65-83.
This journal article is available at ScholarlyCommons:http://repository.upenn.edu/ese_papers/317
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Barry G. Silverman* Gameplay, Interactive Drama,
Michael Johns
and Training: Authoring
Ransom Weaver
Josh Mosley Edutainment Stories for Online
Electrical and Systems Engineering
Players (AESOP)
School of Engineering and Applied
Science
University of Pennsylvania
Philadelphia, PA 19104-6315
Abstract
This paper describes initial efforts at providing some of the technological advances
of the videogame genres in a coherent, accessible format to teams of educators. By
providing these capabilities inside an interactive drama generator, we believe that
the full potential of educational games may eventually be realized. Sections 1 and 2
postulate three goals for reaching that objective: a toolset for interactive drama
authoring, ways to insulate authors from game engines, and reusable digital casts to
facilitate composability. Sections 3 and 4 present progress on those tools and an in-
depth case study that made use of the resulting toolset to create a large interactive
drama. We close with lessons learned to date and a look at the remaining chal-
lenges: the unpleasant reality that state- of-the-art tools are not yet able to boost
the productivity of edutainment authors.
1 Introduction and Goals
Weenvisionafuturewheremanygamesexistthathelppeopletocope
withtheirhealthissues,childrearingdifficulties,andinterpersonaltraumas.
Further,thesegameswillbesocompellingandeasytorevisethatmanyplayers
willfeelcompelledtocontributetheirownstorytotheimmersiveworld—a
contributionthatisbothself-therapeuticandthathelpsotherswhoseesome
oftheirowndilemmainthatstory.Thiswillbeanindustrythatisconsumer
grown,sincetheywillbethecreatorsofnewgamesforotherconsumers.Asa
fewofmanypossibleexamples(1)parentswillexperiencewhatotherparents
ofhandicappedchildrenhavestruggledwithandovercome,(2)childrenwho
arebullieswilllearnwhattheirbullyingdoestootherkids,and(3)people
withchronichealthissues(overeating,diabetes,heartdisease,etc.)willlearn
whathappenswhenself-denialandpoordietsprevail.Weenvisionthatasin-
gleunderlyinggameeditingenvironmentandalterablecastofdigitalcharac-
terscanbeusedtofacilitatesuchavarietyofgameswiththerapeuticvalue.
Atpresenttherearemanyobstaclestothisvision:(1)thevideogameindus-
tryoffersaddictive,immersiveentertainmentandprovidesmostoftheseeds
forthisindustrytogrowfrom;however,theirgameshavelittleeducationfo-
Presence,Vol.16,No.1,February2007,000-000
©2007bytheMassachusettsInstituteofTechnology *[email protected].
Silvermanetal. 1
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2 PRESENCE: VOLUME 16, NUMBER 1
cusandtheyprovidefewifanytoolsdirectlyreusablein storycreationbytheplayer—andthesecompetingaes-
thisniche;(2)thecomputer-basededucationfielddoes theticsneedtoberesolvedifpedagogicalgamesareto
produceinteractivetrainingtools,however,theseare achievetheirpotentialingeneral.
heavilycorporateandgovernmenttrainingbasedand Morethananyothermechanicofgameplay,anarra-
havealmostnoentertainmentvalueandhencearen’t tiveinagameraisestheideaofdestroyingthecentral
spontaneouslyfuelingmuchconsumerinterest;(3)the aesthetic—thatplayerscreatetheirownstoriesandthat
fieldofmoviesandTVshowwritingcreatescompelling iswhatkeepsthemcomingback.(Mechanicsisaterm
charactersthatconsumerscaredeeplyabout,butthis usedingamedesign.Itmostnearlymeans“functional-
mediumoffersnochanceofinteractivitythatisvitalto ity”onhowgamepieceswork,orhowthegamefunc-
self-discoveryandskilldevelopment;(4)thefieldofhu- tions.)Othergameplaymechanicsmoreorlesshavea
manbehaviormodelingoffersinnumerablemodels storyinsidethem,infactcountlessstoriesinsidethem.
basedonfirstprinciplesofphysiologyandpsychosocial Further,manyofthesemechanicshavebuilt-inskill
dynamics,yetoutsideofafewexperimentalmilitary trainingfunctionsatthesametimethattheypermitun-
simulators,thesearerarelyinsertedintoautonomous constrainedplayandinquiry.Forexample,aracingand
charactersinvideogamesandinteractivedramas;and chasingmechanicincludeslessonsabouthowtochase
(5)thesuccessfuledutainmentofferingstodate(e.g., downbadguysandcutthemofffromescape.Likewise
MathBlaster,ReaderRabbit,OregonTrail,etc.)are acombatgamehasbuilt-inweaponfiringandtarget
monolithic,nonalterablecreationsoftheirproprietors. damagemodels,plusskillchallengessuchasroomclear-
Weneedanextgenerationofenvironmentsthattakes ing,amongothers.Ifoneinvestsintherealismofthese
thebestfromeachofthesefieldsandprovidesthe mechanics,theyprovideusefultrainingandtransferable
neededcapability.Theelementsofthisenvironment skills(Filipczak,1997;Green&Bavelier,2003).The
mostlyexist,buttheyhaven’tbeenproperlyputto- sameshouldbetrueifinteractivedramasarewelldone,
getheryet. particularlyifthegoalofthedramaistolearn,rehearse,
Webelievethatonecouldtaketheimportantele- andtransferskillsininteractingwithpeople;and/orto
mentsthatexisttodayandsynthesizethemintothede- learnhowtopersuadepeopletochangedysfunctional
siredcapabilityforAuthoringEdutainmentStoriesfor behaviorsandbythattolearnhowtocopewithone’s
OnlinePlayers(AESOP).Providedthegameauthoring ownpoorhealthbehaviorsbeforetheybecomeareal
toolbox(whatwecallAESOP)isusableanduseful, worldproblem.Thatis,dramasareessentiallydialog
thengameauthorswillbeabletowriteabouttheirsitu- games,andhenceonemusttakeextraprecautionsto
ationsandgameplayerswillbenefitfromimmersively avoiddamagingthegameplayaesthetic.
experiencingandseeingtheproblemsthatothershave Itisalsoafactthatstudentslearnthemostandretain
hadtodealwith.Thefirstgoalofthisresearchisthusto itthelongestwhentheymustteachatopictoothers
explorealternativewaysforagamegeneratortohelp (Gibbons&Fairweather,1998;Reigeluth,1999).One
authorsintroduceentertainmentandfreeplayintorole alwayslearnsasubjectbetterifoneisconfrontedwith
playinggamesandinteractivedramasthataretraining beingtheteacherratherthanthestudent.Soami-
interventions. croworldcouldbequiteapowerfultrainingdevice
Thisgoaliscompoundedsincelearnerorientedgame ifitaffordsteachingopportunities,orevenbetterifit
designsareoneofthemostdifficultareasindeveloping thruststheplayerintoroleswhereothercharacterswill
videogames.Firstoff,althoughtrainingrequiresplayers bevulnerableanddependentontheplayertoteachfor
toprogressthroughstories(pedagogicallyvaluablesce- asuccessfulconclusiontobereached.Whyshouldthe
narios),atitsheartgameplayisnotaboutinteractive playercaretobecomeateacher?Whatcandrivethem
fictionthoughtherearethosewhobuyinteractivefic- toreachthisleveloflearning?Peoplereflectthiskindof
tiongames.Interactivedramaisallaboutstorytelling passionforvideogamesandatthemovies.Whengame
fromtheauthor,whilegameplayismuchmoreabout mechanicsworkandwhencharactersarelikable,players
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Silvermanetal. 3
(viewers)achieveenormousempathyforthecharacters Itisworthpointingoutthat,fornow,wemadea
(Decker,2002;Hopson,2001;LeBlanc,2002)andare consciousdecisiontobasethiscastandsetsaround2D,
willingtogotogreatlengthstosavethemandtohelp hard-edgedcel-basedanimationsinceresearchhas
themworkouttheirproblems(e.g.,asin“God”games shownthatsubjectswithhealthbehaviorchangeissues
suchasTheSIMS,virtualPetz,andTamagotchi),and oftenallocatelittlecognitiveprocessingtohealthmes-
togoonquestsontheirbehalforassisttheminshifting sages,andfeelgreaterconfidenceaboutbeingableto
theirbehaviorstomoresuccessfulmodelssuchasinrole processandconquermessagesetsintroducedincartoon
playinggames.Inthesemilieus,playersrevealwilling- formats(Green&Brock,2000).However,theunderly-
nesstolearnskillsthatwillhelpthedysfunctionalchar- ingtechnologyalsosupports3Danimation,asisusedin
acterstocope. ourUnrealTournamentgameformilitarytraining.
Atthispoint,letusrestatethefirstgoalasresearching Inaddition,wechoseafinitestatemachine(FSM)
ageneratorthatpermitsauthorstocreateinteractive approachasthebasisforourdialogmodelandour
roleplayinggamesthatpreservethecentralaestheticof scriptwritingapplication.TheFSMsmayberepresented
gameplay,thatutilizestealthlearningandself-discovery visuallywithinadirectedgraphortree.Edgesrepresent
inmicroworldsfortrainingandbehaviorchangepur- thevariousdialogchoicesavailabletotheuseraftera
poses,andthatincorporatelearningbyteaching.Asec- givennodeplaysout.Eachnodecontainsbothdialog
ondgoalistoprovideahighlevelgraphicaluserinter- andanimationinstructionsfortheavatarandnon-player
faceforthegenerator,andbythattoinsulateauthors characters(NPCs)tocarryoutandthatmaybeacti-
fromhavingtolearnagameengine’sdetails.Acorollary vatedinparallel.Thisapproachallowedourwritersto
tothatgoalisthatthegeneratormustitselfbekept choreographtheanimationofmultiplecharactersto
fairlysimpleifthelaityistosucceedinusingit. occursimultaneously.TheAESOPgeneratoriscur-
rentlyimplementedtohelpauthorswiththesimple
FSMapproachandsothatitcanencapsulateanddeliver
2 Creating Stories with Free Play theinteractivegametootherdevicesthatdisplayand
trackgameplay.Section3willexplainthisstructurein
Asalreadymentioned,weareseekingtosetupa moredetail.Beforethat,however,itisimportantto
generatorthatcanexposeconstructsandparametersof furtherexplorehowAESOPseekstosatisfythefirstde-
astoryworldsothatnewinterventionsmaybemore signgoal.
readilyauthoredthatpromotefreeplayandentertain- Wefreelyadmittoseveraldesignbiasesinourap-
mentwithinanarrativestructure.Tosupportthisre- proachandmakenoattempttojustifythese.Theyin-
search,weareattemptingtoproduceacastofanimated clude:
puppetsandsets(introducedinwhatfollows)inaway
thattheycanbereusedformanystoriesthisisour ● adesiretotry(2D)graphicsratherthantextonly;
(thirdgoal).Thisistheideaofacomposableandreus- ● abeliefthatthetensionbetweenentertainmentand
educationcanberesolved;
ablestoryworld,includingdigitalsets,castmembers,
andCampbellianarchetypesthatcanbeadaptedand ● abeliefthatitispossibletoauthorhighlybranch-
ing,interactivestoriesthatarecoherentandsensi-
extendedforfurthersequelsnotevenyetanticipated.
ble.
Ourideasforreusablecastsandarchetypesfollowfrom
worksuchasCampbell(1973),Decker(2002),and
Propp(1968),aswellashowtheyareusedinfranchise
2.1 Narrative Intelligence
games,comics,andserials.Weincludecharactersofdif-
ferentages,genders,andbackgrounds/ethnicities,and Thefieldthatsomerefertoasnarrativeintelli-
intherolesofhero,sidekick,allies,opponents,trick- gencehasrecentlyproducedanumberofrichideasfor
sters,lovers,andsoon. incorporatingnarrativeintogameworldswithouttotally
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4 PRESENCE: VOLUME 16, NUMBER 1
sacrificinggaming’scentralaesthetic.Inthisresearch, gamefieldtodatetendtoapproachthisconcernbyin-
wesynthesize,adapt,andextendseveraloftheseideas terspersingfreeplay/inquiryandplayerstorycreation
asthissectionwillnote.Noneoftheliteraturetodate withplayer-selectedchoicepointsforadvancingthe
hasdirectlyaddressedthetopicoflearningbyteaching, story.Atthesechoicepoints,theplayerapproaches
sothisplacesusinanewrealmthatdrivesourinquiry. charactersorotherdevicesthatrevealmoreoftheau-
Also,verylittleifanyofthenarrativeintelligencere- thor’sstoryandthatadvancethemtothenextsceneof
searchtodatehasaddressedhowtoassiststoryworld thedrama.Inthismanner,adramaeventuallyunfolds.
authors,soseveraloriginalcontributionsareneeded Somesuccessfulexamplesofthisblendingofstoryand
hereaswelltotrulyrealizeourresearchgoals.Weare gameareGrandTheftAutoandDeusEx,amongoth-
creatingtheAuthoringEdutainmentStoriesforOnline ers.
Players(AESOP)generatoraspartofthisresearchand SimilartothisistheapproachbeingtakenintheAr-
areseekingtohaveitassistwithauthoringconstructsas my’sMissionRehearsalEnvironment(MRE;Swartout
F1 portrayedinFigure1andasfurtherdescribedinwhat etal.,2001);however,unlikethepopulartitles,this
follows. approachisconcernedwithimpartingdoctrinallycor-
Fromtheplayer’sperspective,whentheyencountera recttrainingobjectives.TheMREapproachrequires
storyworldsuchasinFigure1a,theydonotwishtobe authorsto(1)deconstructthestoryintothesmallest
placedonmetaphoricalonrails—astorylineforcingthe parts(scenenodes)whereautonomouscharacterand
playerdownanarrowpaththatisauthorspecified.For playerfreeplaycanbepermitted,and(2)toidentify
example,Figure1ashowsfourareasoftownwhere graphtransitionsthataregateconditionsfortriggering
scenes(andtrackingobjectives)exist.Onecanlinearize scenesand/orforallowingscenestobeomittedwith-
theworldorallowtheusertomeanderinandoutof outlossoftrainingvalue.Thisapproachpermitsthe
thesefreely.Thebestnarrativesolutionsfoundinthe playertoexploreanoderepeatedly,gettingbetterwith
eachtryandthroughexitnodefeedback.However,this
approachisfordoctrinallycorrecttrainingthatrequires
repetitionforimprovement.
Inthecurrentresearchweareinterestedinlearning
byteaching,inmentalmodeltransfer,andinbehavior
shiftingasmentionedearlier.Thisrelaxestheneedto
repeattheidenticalscene,andaffordstheopportunity
forscenestoholdsurprisingplotreversalsifyouplay
themdifferently.Forexample,Figure1bzoomsusin
onaplotordialoggraphforasamplesceneorquestof
thestoryworld.Herethenodesandedgesareasde-
scribedfortheFSMinthepriorsection.Dependingon
theplayer’spersonalgoals,entertainmentobjectives,
styleofplay,andconfidence,amongotherfactors,they
maydecidetopursueverydifferentavenuesthrougha
scene’sdialoggraphandinfactthroughtheentirestory
world.Thiscanbebotheducationalandentertaining.
MonkeyIslandisanexampleofatitlethatincorporates
argumentationtacticsinthismanner,thoughinthat
titlethereisonlyoneoutcomeandpathoutofascene
Figure1. Sampleinsertionpointsfornarrativeintelligenceto regardlessofdialogchoices.PopulargamessuchasCivi-
minimizeperceptionsoflimitingfreeplay. lization,Black&White,andEverQuest,inturn,have
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Silvermanetal. 5
richeroutcomepossibilitiesandlettheplayerlearn Therehavebeenanumberofinvestigationsintocon-
abouttheworld’semergentnatureandhowtheyhave versationswithautonomousagentsoutsideofstories
tolivewiththeworldstheycreateandthepersonasthey and/orinfixedplotgraphsandtheirfindingshavepo-
project.Inallthesegames,linesofintellectualinquiry tentialhere.Someoftheearliestworkdealtonlywith
haveconsequencesanddiscoveriesresultfromexplora- simpleanimationandkinestheticissuessuchasbreath-
tion. ingandblinking,lipsynching,andfacialexpressions—
Thesametypesofexplorationcanexistinpedagogi- thingswelabelasthepresentationlayerinFigure1d
callyorienteddialoggraphs.Earliereffortsintroduce (e.g.,seeLasseter,1987).Moreintriguing,however,is
suchpossibilitiesbyprovidingsidecharactersthatcoach workonthehigherlayersofFigure1dandhowthey
andcajoleaplayerbacktothepedagogicallypreferred mightbeintegratedintodialogplotsassuggestedin
path(Marsella,Johnson&LaBore,2000;Silvermanet Figure1c.Wedefinethesimulationlayerofanagentas
al.,2001)ofadialoggraph.Inthetypesofstoryworlds howitperformsintheworld,forexample,navigation,
wecurrentlyenvision,however,thelearningcanbejust collisionavoidanceandcollisiondamage,andphysio-
aseffectiveifacompanion,sidekick,or“windowchar- logicalneedsandhealthneeds.Insomecharacters,we
acter”regretsaloudtheplayer’sdecisionsandthenon embeddedanumberofvalidatedreservoirmodelsof
itsowndirectlyperformsthedysfunctionalcharacter bodyorgansandfunctions(Silvermanetal.,2002).
trainingandpersuading(Decker,2002).Intheory,the LessrealisticmodelsarewidelyusedinpopularGod
playershouldevenbeabletoadoptapotentialstory- games;however,thereisneveranystorydesignedinto
worldantagonist’scausesandbeentertainedbyhelping it,andplayersmerelyascribestorywhenuncorrelated
tosupporttheantagonist’sobjectivesthroughoutthe eventsarise.Inourworktheseeventuallyareintended
storyworld,yetsuffernolossoflearningasaresult.Us- toprovidemanypotentiallyengagingtrainingdialog
ingthistechniqueofgameplay,wearefindingthatsuch opportunities,particularlywithcharactersthatattempt
dialogplotregionsandtheresultingopportunitiesto todenyormislabeltheirsymptoms,riskfactors,and
tryout“bothsides”ofaconflictcanenhancethedrama lifestylehabits.
andhelpboostreplayability(seeCaseStudyofthispa- Likewise,thebehaviorlayerinvolvescharacters’emo-
perandSilverman,Johns,&Weaver,2003). tionsandmotivations,planning/choosingstyle,and
Thereasonplayerscanadoptthecauseofeitherside generalpersonalityvariablesincludingcopingmodes.
andpotentiallysuffernolossoflearningistiedtohow Oneideahereistoallowthemoodsandpersonalitiesof
welearninstories.Instorytellingtheory,thelisteners, thenon-playercharacters(NPCs)toresponddynami-
orparticipants,areviewedascontainingsignificantun- callyandemergentlytodirectplayerinteraction.The
derstandingandknow-howalready,andthestoryisbut NPCsincludeparameterizedmodelsofautonomous,
afusetoignitetherecipientsintosynthesizinganew emotivebehavioranddifferenttypesofresponsesto
conceptualizationforthemselves.Thisisalsoconsistent playeractionsordialogs.TheVirtualTheatreProject
withpersuasiontheory,suchasinthePersuasionLikeli- (Hayes-Roth&Rousseau,1997)hasexploredthiscon-
hoodModel(Petty&Cacioppo,1986)whichstates ceptforfixedplotgraphsandshownthatplayersper-
thatrationalargumentsareunlikelytopersuade.Rather ceivesignificantdramaticvariabilityandstory-creating
itistheperipheralcuesthataremodeledthatconvince potential,eventhoughtheplotisfixed.Anearlyproto-
theaudience.Thusthemanymoviescenesofactors typeofHeartSenseGamehaslikewisedeployedanau-
smokingduringorafterasignificantactivityhavefar tonomouscoach/companionthataltersitsmood,
morepowerthanallthepublichealthmediacampaigns emotion-directedutterances,andphysicalexpressionsas
layingouttherationalargumentsaboutadversehealth afunctionofwheretheplayerstraysintheplotordia-
effects.Aslongasaninteractivedramasuccessfully loggraphandfoundthisreducesplayerdifficulties(Sil-
modelsthedesiredhealthbehaviors,thetheorysuggests vermanetal.,2001).Inthecurrentresearchwehave
theplayerwillpickuponit. eliminatedovertcoaching,butareconsideringthisidea
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6 PRESENCE: VOLUME 16, NUMBER 1
forkeycharacterssotheyaltertheirpersonalityeach agentinthestoryworldintheformofFSMsthatare
timeyouplay.Thisinturncouldfurthertheperceived senttothegameengine.WiththeuseofanXMLinter-
playervariabilityandsenseoffreeplay.Italsowould face,theAESOPeditorsuitebecomesengineindepen-
meanplayersmustuseadifferentpersuasionstrategy dent.ItsFSMscouldintheorybeplayedbyanyofa
eachtimetheyreenterascene. varietyofgameenginesthatrunNPCsandavatars.Fig-
Silvermanetal.(2002)demonstratehowanumberof ure2overviewsthatarchitecture,andthediscussion F2
modelsfromthepsycho-physiologicalliteraturerele- thatfollowsprovidesfurtherdetails.
vanttothesetwolayers(simulationandbehavior)can Whenbuildingapieceofedutainment,thegenerator
contributetomakingagentsautonomousandneed- mustsupporttheentiregroup,includingtrainingcon-
reservoirdrivenintheircopingstylesandemotivedeci- tentdevelopers,storywriters,andgameauthors.Agoal
sionmaking.ThisisanattempttomovebeyondBates’ ofthisresearchwastostudyoneortwosuchgroupsas
believableandbroadagents(Mateas,1997)intothe theyattemptedtocreateanedutainmentsystem,elicit
realmofreliablemodelsofhumanperformancecali- theirdesignprotocolsandintermediategamerepresen-
bratedagainstfielddata—anareawherelearningsys- tations,andtotryandcraftageneratorenvironment
temsmustdepartfromentertainment. thatmightbettersupporttheirmutualandcollaborative
Afinalissuefacingstorytellinginsimulatedworldsis efforts.Inthelatter,wewerehopefulofplacingvarious
thatitforcestheplayerintowhatisarguablytheworst toolsandversionsofageneratorinfrontofthemto
furthertherequirementsoftheobservationandelicita-
sideofhuman-computerinteraction,thatofthecom-
tionprocessandtostudyenvironmentdesignconcerns.
puter’spoorconversationalcapabilities.Aswithvoice
Whereandwhenwedidnothaveaspecificallyneeded
menusystemsonthetelephone,themachine-generated
tool,weintendedtosupporttheneedmanually,bydi-
voicesarestilted,theirabilitytohandlenuancesispoor,
rectlyprogrammingtheauthoringneedand/orgame
andtheyoftenmisunderstandthespeaker.Uptonow
mechanic.Inthisfashionweareengaginginatradi-
wehaveusedatexttospeechsystemduringauthoring
tionalspiralsoftwaredevelopmentoftheAESOPgener-
butreplaceitwithactorvoice-oversoncethepartsare
ator.
finalized.Wecompletelyavoidthespeechrecognizers
Intermsofspecifics,theleadauthorofthispaper
andinsteadrelyondialogmenus,whichraisesseveral
servesasprincipalinvestigatorofboththeAESOPgen-
difficulties.Specifically,theriskofdialogmenusisthat
erator(Silverman,Johns,etal.,2003)andtwoedutain-
thedesignerhasneglectedtoincludeoptionstheplayer
mentprojectsthataremakinguseofit—theHeart
wouldliketoseevoiced,oriftheyarevoiced,hasn’t
includedmechanicsintheothercharacterstosupport
theideaintheplayer’shead.Sofarinthecasestudy,
however,wehavenotencounteredthisdifficultyand
believethelargedegreeoffreeplaymentionedinthis
sectiontendstominimizethedialogmenurisks.
3 The AESOP Generator
AESOPisintendedasafrontendauthoringaid
thatincludesplotanddialogeditingGUIs(graphical
userinterfaces),storyworldtemplates,palletesofreus-
ableparts,digitalcastmembers,autonomousbehavior Figure2. ArchitectureoftheAESOPgeneratorthatsupportsthe
modules,andreusableart/animationassets.Itsoutput threegoalsofcreatingpedagogicalinteractivedramaswithreusable
isautomaticallyparsedintoXMLinstructionsforeach casts/objectsandinsulatesauthorsfromcommercialsystems.
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Silvermanetal. 7
SenseGame(HSG)roleplayingdrama(Silvermanetal., actersrepletewithgrowingstoresofgestures(Flash
2001)andarecreationofMogadishu/BlackHawk movies)andactionsonecanassignwithamouse-click
Down(BHD)crowdscenesforafirstpersonshooter tothecharacterpuppets(seeSection3.2).Oneauthors
scenario(Tothetal.,2003).Thispaperfocusesprimar- dialogandactioninthegrapheditortool.Thispro-
ilyontheHSGandDirectorversionoftheAESOP ducesscriptsintextandgraphmarkuplanguage(GML
generator;thoughdiscussionattimeswillmentionfea- orXML)thatareinstructionsetsorFSMsthattheen-
turesandlessonsoftheotherapplications. ginecanrunontopofDirectorwiththehelpofatext
TheHSGstartedlastquarter2001,andsincethat tospeech(TTS)processorandthelibraryofFlashmov-
timetheHSGdevelopmentgroupmetattimesweekly iesforeachcharacter’sgesturesandactions.Thusthere
andatothertimesbimonthlyfor90minuteface-to-face isnoneedtoprograminDirector,anddevelopersau-
designbrainstormingandfeedbackdiscussions.The thorroleplayingdialogscenesandwatchthemacted
contentoftheseinteractionsisdescribedinthecase outwiththepushofabutton,providedtheydonot
study(Section4).Thisgroupincludedsixfacultyinves- expectgesturesandactionsthatarenotyetintheFlash
tigators,twograduatestudentresearchers,attimesup moviestoresforeachcharacter.
tonineundergraduatedigitalmediadesignandsystems Attimeswehaveincludedautonomousemotive
engineeringstudents(helpingwithart,animation, agentsinearlierversionsofHSG,agentscapableof
sound,voice-overs,etc.),andonejuniorandonesenior emergentbehavior(Silvermanetal.,2002;Silverman,
screenwriter(part-time,freelance).Theyweresupported Johns,etal.,2003),whiletheBHDandotherapplica-
inbetweenmeetingsviaavarietyofcollaborativetools tionsmakesubstantialuseofsuchautonomy.Theseare
includingthreadedchat,web-basedftprepository(or- NPCagentsthatoperatewiththeirownbehaviorgoals,
ganizedintosub-teammemorybins),emaillistserv,and standards,andpreferences,andthatcanreacttoand
generalemail.Threadedchatwashighlyusefulatthe effectthedramaandtheplayer.Thecurrentarticle
outsetfordiscussinglearningobjectivesandgameme- omitsdiscussingthesecharacteristics,butwehavenu-
chanics,but,asthethreadedconversationsgrew,people merouspapersonthistopic(e.g.,seeSilvermanetal.,
foundthemcumbersomeandresortedtoemailanddi- 2002andSilverman,Johns,etal.,2003,amongoth-
rectmeetinginstead.Theftprepositoriesfolloweda ers),andwecontinuetoworkonthechallengesofinte-
similarpattern. gratingauthor-drivenvs.agent-drivenstoryelements.
Figure2showstwoboxeslabeledEditorSuiteand
Engine.Varioustoolswereplacedintotheseboxesand
3.1 GraphEdit Tool
evaluated/improvedovertime,assubsequentsections
ofthispapersuggest.Asanoverviewofthatdiscussion, OurFSMeditorisamodifiedversionofVisual
theplotmap(acts,scenes,etc.)andcharacterbacksto- GraphsforJava,developedatAuburnUniversity.To
riesstartedastext-onlydescriptions,evolvedtoaman- facilitateourparticularneeds,thesecondauthorofthis
uallyfilledinmultimediasetofwebpages(www.seas. paperaddedcustomdialogboxesforthedatawema-
upenn.edu/(cid:2)barryg/heart/index.html),andisnow nipulate,andaddedsupportfortheXMLoutputre-
targetedtobecomeaninteractiveeditorthatwillassist quiredbyourgameengine.
inmerginglearningobjectiveswithstorywritinggoals. Inourgraphs,nodescontainuninterruptibleseg-
Theearliestversionsofthebranching,interactivedialog mentsofstorytelling,andedgescorrespondtothe
scriptweretable-basedwhichwasthenreplacedbya choicesgiventotheuseraftereachnodeplaysout(see
directed-grapheditor(Section3.1).Theearliestver- Figure2).Withineachnodeisasetofbehaviorsas-
sionsofthegameengineexistedpriortotheartwork/ signedtovariouscharacters,arrangedasatree.There
Flashmoviestoresandutilizedstickfigures(withtextto areelevenpossiblebehaviors,themostcommonbeing:
speech)toactouttherolesanddialogfromthescript. 1)SOUND,whichcausesthespecifiedcharactertolip-
Subsequentversionsincludedalibraryofsetsandchar- synchalineoftexteitherdefinedbyawavfileor,failing
tapraid4/z92-psen/z92-psen/z9200107/z922006d07a sangreyj S(cid:1)9 11/17/06 22:33 Art:z92-2006
8 PRESENCE: VOLUME 16, NUMBER 1
Figure3. IllustrativescreensofthegraphEdittoolforconstructingbranchingdialogandaddingchoreographicandmultimediainstructionsto
FSMs.
that,atext-to-speechgenerator;2)ACTION,which beginwithaspeechbehaviorforJack,andthenaddtwo
causesthecharactertoperformsomespecificanimation; childnodes:oneforJoe’sreplyandoneforhisgesture.
or3)MOVE,whichcausesthecharactertophysically SincebothbeginafterJackstopsspeaking,theywillex-
movefromonepositiononthescreentoanother. ecuteatthesametimeandJoewillspeakwhilewaving.
Whenonebehaviorfinishes,allofitsdirectchildrenare Figure3showsourdialoggraphauthoringtool.The F3
executedinparallel.Thisallowsforauthorstospecify mainscreenshowsthestructureofthegraph,with
thetimingofvariouscomponentsofascenewithout edgesrepresentingtheoptionspresentedtotheuser
knowingspecificdetailsabouttheartorvoiceassetsthat andnodes,asdescribedabove,containingthebehaviors
willeventuallybeputinplace. thatresult.Overlappingthiswindowinthelowerleftis
Oncethetoolisutilized,onecansavethegraphout thenodeeditingdialog,inwhichthebehaviortreefora
toXMLformatwhichwillbeusedbythegameapplica- givennodeiscreated.Finally,inthelowerrightisthe
tionandengine. behaviorpropertiesdialog,whichgivescontrolover
SupposewewanttocreateasceneinwhichJacksays specificaspectsofeachbehavior.Forexample,agesture
“Hello,”andJoereplies“Hi”whilewaving.Wewould behaviordialogcontainsamongotherthingsalistfrom