Interactive Storytelling - lecture slides 2012
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Interactive Storytelling - lecture slides 2012

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Lecture slides from the course Interactive Storytelling (autumn 2012). The aim of the course is to present the key concepts behind interactive storytelling as well as to review the proposed and ...

Lecture slides from the course Interactive Storytelling (autumn 2012). The aim of the course is to present the key concepts behind interactive storytelling as well as to review the proposed and existing systems.

The course begins with an introduction to storytelling and interactivity. There are two approaches to combine them: In character-centric storytelling, we focus on creating believable and complex characters and the story emerges from their interaction in a given setting. In author-centric storytelling, we focus on creating a plot that controls the character and adapts to changes while keeping the story dramatically compelling. The course ends with a broad review of existing and proposed interactive storytelling systems.

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Interactive Storytelling - lecture slides 2012 Interactive Storytelling - lecture slides 2012 Presentation Transcript

  • Interactive Storytelling © 2008–2012 Jouni Smed Jouni Smed jouni.smed@utu.fi http://www.iki.fi/smed
  • Course syllabus • objective: • credits: 5 cp. © 2008–2012 Jouni Smed ‣ to present the key concepts behind interactive storytelling ‣ to review the proposed and existing interactive storytelling systems
  • Lectures • lecture times ‣ Tuesdays 10–12 a.m., lecture room λ (C1027) ‣ Wednesdays 10–12 a.m., lecture room β (B1032) ‣ no lectures: November 6, November 7, November 27, November 28 © 2008–2012 Jouni Smed • October 30 – December 5, 2012
  • Assessment • assessment is based on both ‣ writing an essay and ‣ taking an examination © 2008–2012 Jouni Smed • you cannot pass the course without both!
  • Examinations • electronic examination ‣ opens December 10, 2012 ‣ closes March 31, 2013 • you can take the examination at most three • for instructions and examination time reservations, see https://tenttis.utu.fi/ © 2008–2012 Jouni Smed (3) times
  • Essay • an essay of 10–15 pages on a chosen topic (in English or in Finnish) ‣ topics and material are available in the course’s moodle page ‣ the essay has to follow the given style standard ‣ deadline: December 13, 2012 (Thursday) 2 p.m. ‣ papers returned after the deadline will not be graded! © 2008–2012 Jouni Smed • the essay is returned as a PDF file
  • Essay (cont’d) • grades and possible teacher’s comments are announced privately through the course’s moodle page • all returned essays will be published in the ‣ grades or teacher’s comments are not made public © 2008–2012 Jouni Smed course’s moodle page in December 2012
  • Quick walkthrough 3. Return the PDF version of the essay before December 13, 2012, 2 p.m. using the essay return page. 4. Check your essay grade in the course’s moodle page. 5. Schedule and take an electronic examination. © 2008–2012 Jouni Smed 1. Pick topics that interest you from the list of topics. 2. Write the essay.
  • Grading • grading is based on 20 points ‣ the examination gives at maximum 10 points ‣ the essay gives at maximum 10 points • to pass the course you need more than 10 ‣ you cannot pass the course without both taking the examination and writing an essay! © 2008–2012 Jouni Smed points
  • Grading (cont’d) • final grade: grade: 1 ‣ points: (12, 14] grade: 2 ‣ points: (14, 16] grade: 3 ‣ points: (16, 18] grade: 4 ‣ points: (18, 20] grade: 5 © 2008–2012 Jouni Smed ‣ points: (10, 12]
  • Course homepage © 2008–2012 Jouni Smed http://bit.ly/intstory2012
  • Contents 1. Introduction to interactive storytelling 2. Analysis of storytelling 3. Strategies for interactive storytelling 4. Characters 5. End-user 7. Systems 8. Discussion and conclusion © 2008–2012 Jouni Smed 6. Author
  • © 2008–2012 Jouni Smed Introduction to interactive storytelling
  • Interaction • “Reciprocal action; action or influence of persons or things on each other.” (Oxford English Dictionary) active agents in which each agent alternately listens, thinks and speaks” (Crawford, 2005) © 2008–2012 Jouni Smed • “a cyclic process between two or more
  • Storytelling is about… • the reasons for actions (not actions) • people © 2008–2012 Jouni Smed (Spierling, 2002)
  • Linear psychological narrative • psychological buy-in by the audience • willing suspension of disbelief © 2008–2012 Jouni Smed (Perlin, 2005)
  • Typical features of storytelling • contingency: story time/space vs. real time/ space • narrative representation: the way of presentation generation process (Aylett & Louchart, 2003) © 2008–2012 Jouni Smed • presence: viewer sharing story time/space • interactivity: participation in story
  • Comparison of different narrative forms Cinema Theatre Literature Virtual reality Contingency low medium low strong Narrative representation visual visual mental visual not physical physical Interactivity no no/yes no yes © 2008–2012 Jouni Smed Presence not physical not physical but immersive
  • Models of user engagement • actual roles that users play in relation to the narrative experience (Aylett & Louchart, 2007) Examples none conventional audience non-participant control conventional authoring; film non-participant influence Forum Theatre; The Sims participant control points branching narrative freely participating characters LARP, emergent narrative © 2008–2012 Jouni Smed Degree of interactivity
  • Examples of interactive storytelling • inventing and telling a story to an audience (e.g. children) • (live action) role-playing games • improvisational theatre (e.g. Forum • tour guiding • teaching © 2008–2012 Jouni Smed Theatre)
  • Interactive digital storytelling • interactive digital storytelling application is © 2008–2012 Jouni Smed “designed for users (interactors) to take part in a concrete interactive experience, structured as a story represented in a computer” (Peinado & Gervás, 2007)
  • Three partakers Author Interactive storytelling system End-user © 2008–2012 Jouni Smed Characters
  • Forms of interactive entertainment computer games interactive fiction hypertext fiction digital storytelling scriptwriting software role-playing games (RPGs) simulators narrative intelligence (Crawford, 2005) © 2008–2012 Jouni Smed • • • • • • • •
  • Uses for interactive storytelling systems • art • entertainment ‣ computer games • education ‣ children ‣ information kiosks ‣ tour guides © 2008–2012 Jouni Smed • guidance
  • Narrative thinking • fundamental structuring of the human experience • autobiographical memory holds stories about the self © 2008–2012 Jouni Smed (Aylett & Louchart, 2007)
  • Narrative immersion • spatial: a sense of place and pleasure taken in exploring the story-world • temporal: a desire to know what will happen next (curiosity, surprise, suspense) • emotional: affective reactions to the story (Ryan, 2008) © 2008–2012 Jouni Smed and to the characters
  • Conventional narrative constructed story presented story spectator experienced story © 2008–2012 Jouni Smed author
  • Interactive narrative user experienced story characters external events author © 2008–2012 Jouni Smed generated story
  • Narrative loop EVENTS cause Affective changes World state changes cause cause ACTIONS (Aylett et al., 2011) © 2008–2012 Jouni Smed cause
  • Degree of interactivity 1. speed ‣ fast turnaround 2. depth ‣ human-likeness ‣ functional significance ‣ perceived completeness (Crawford, 2005) © 2008–2012 Jouni Smed 3. choice
  • How to interact with stories? 1. what would change? 2. what would stay the same? 3. how do we make such a thing? (Perlin, 2005) © 2008–2012 Jouni Smed 4. where is the artist/author located wrt. the observer/reader
  • Problems for interactive drama 1. temporal management of actions: interesting narrative from the choices? 2. multimodal representation of character’s actions in a real-time 3D environment 4. authorability: artists should be able to express themselves (Szilas et al., 2007) © 2008–2012 Jouni Smed 3. interpreting player’s actions
  • Challenges for story generation 1. themes ‣ betrayal, yearning, love, revenge etc. 2. story control ‣ the story must remain dramatically compelling 3. strong, autonomous characters ‣ characters’ reasonable reactions and beliefs (Bringsjord, 2001) © 2008–2012 Jouni Smed 4. personalization
  • R&D challenges 1. agency ‣ primary feature offered to the players ‣ player has to be able to affect the plot directly 2. generation 3. interface ‣ expressive, multi-modal interface © 2008–2012 Jouni Smed ‣ real-time generation of content ‣ building blocks
  • R&D challenges (cont’d) 4. connecting generation and interface ‣ planning and drama management 5. terminology (Stern, 2008) © 2008–2012 Jouni Smed ‣ young field still lacks proper terms ‣ e.g., ‘storytelling’ or ‘storymaking’
  • Narrative paradox • “pre-authored plot structure conflicts with the freedom of action and interaction characteristics of the medium of real-time interactive graphical environment” © 2008–2012 Jouni Smed (Aylett & Louchart, 2007)
  • © 2008–2012 Jouni Smed Analysis of storytelling
  • Sources • Aristotle: Poetics (ca. • Vladimir Propp: • A.J. Greimas • Roland Barthes • Claude Bremond • Brenda Laurel: • Joseph Campbell: The • Janet Murray: Hamlet • Russian formalism (1916–1930s) Morphology of the Folktale (1928) Hero with a Thousand Faces (1949) Computers as Theatre (1991) on the Holodeck (1997) © 2008–2012 Jouni Smed 335 BCE)
  • Aristotle: Poetics Thought Language Pattern Enactment © 2008–2012 Jouni Smed Material cause Character Inferred formal cause Action
  • Aristotle: Narrative forms ‣ events represented through verbal narration (diegesis) ‣ focus on the exploits of a solitary hero ‣ story can be endlessly expanded ‣ motivations of the hero remain fairly simple • dramatic ‣ events represented through the imitation of action (mimesis) ‣ focus on the evolving networks of human relations ‣ action is mental rather than physical ‣ the dramatic arc © 2008–2012 Jouni Smed • epic
  • a) exposition b) inciting incident c) rising action d) crisis e) climax f) falling action g) dénouement complication e d c a b f g time © 2008–2012 Jouni Smed The dramatic arc
  • Third narrative form: Epistemic narrative • emerged in the 19th century • superposition of two stories ‣ events that took place in the past ‣ an investigation that leads to their discovery • driven by the desire to know (e.g. mystery (Ryan, 2008) © 2008–2012 Jouni Smed story)
  • Interactivity and narrative forms ‣ accomplishement of a mission ‣ used in many games • epistemic ‣ player as a detective ‣ author-defined story – variable story ‣ elucidation of the mystery until the solution is found • dramatic ‣ most difficult to implement ‣ goals of characters evolve together with their relations ‣ requires constant redefinition ‣ simulation of human reasoning (Ryan, 2008) © 2008–2012 Jouni Smed • epic
  • Russian formalism: Model of narrative 1. Fabula ‣ logically and chronologically related series of events caused/experienced by the characters in the storyworld 2. Sjužet 3. Media/text ‣ the surface of the story expressed in language signs © 2008–2012 Jouni Smed ‣ the finished arrangement (i.e. the plot, сюжет) of the narrated events as they are presented to the reader
  • Vladimir Propp: Morphology of the Folktale ‣ “act of a character defined from the point-ofview of its significance for the course of action” ‣ independent from the character who performs it © 2008–2012 Jouni Smed • analysis of Russian folktales • 31 narrative units (i.e. narratemes) • character function
  • Narratemes and spheres • introduction ‣ βγδεζηθ • the body of the story ‣ ABC↑ • the donor sequence • the hero’s return ‣ ↓PrRsoLMNQExTUW © 2008–2012 Jouni Smed ‣ DEFGHJIK
  • α – initial situation ↑ – departure ↓ – return β – absentation D – the first function of the donor Pr – pursuit, chase E – hero’s reaction o – unrecognized arrival δ – violation ε – reconnaissance ζ – delivery η – trickery θ – complicity A – villainy F – provision or receipt of a magical agent G – spatial transference between two kingdoms, guidance B – mediation, the connective incident H – struggle C – beginning counteraction I – victory J – branding, marking K – resolution Rs – rescue L – unfounded claims M – difficult task N – solution Q – recognition Ex – exposure T – transfiguration U – punishment W – wedding © 2008–2012 Jouni Smed γ – interdiction
  • Example sequences ‣ δηθ – the villain succeeds in deceiving the victim ‣ DE – the hero is tested to get a magical agent ‣ HJ – the hero fights and gets injured ‣ ↓oLQEx – the hero returns but a false hero has taken his place; the hero is recognized and the false hero is exposed © 2008–2012 Jouni Smed ‣ ↓oMNQ – the hero returns but is not recognized until he passes a test
  • Example tale • A tsar, three daughters (α). The daughters • αβδABC↑H-IK↓W © 2008–2012 Jouni Smed go walking (β), overstay in the garden (δ). A dragon kidnaps them (A). A call for aid (B). Quest of three heroes (C↑). Three battles with the dragon (H-I), rescue of the maidens (K). Return (↓), reward (W)
  • • Villain • Donor • Helper • Princess (and her father) • Dispatcher • Hero • False hero © 2008–2012 Jouni Smed Character roles
  • Moves • list of functions that make a subsection of ‣ one move follows directly another ‣ new move begins before the end of old move ‣ second move is interrupted by a third move ‣ two villainies occur at once ‣ two moves have a common ending ‣ two protagonists part at a road marker with an exchange of signalling objects © 2008–2012 Jouni Smed the story (usually ending on F, K, Rs or W)
  • Joseph Campbell: The Hero with a Thousand Faces • monomyth (i.e. the hero’s journey) ‣ common pattern with strong reference symbols • symbolic representation of the passage ‣ departure ‣ initiation ‣ return © 2008–2012 Jouni Smed from childhood to adulthood
  • Separation Innocent world of childhood Freedom to live Master of two worlds Rescue Call to adventure Magic flight Refusal of call Refusal of return Supernatural aid Crossing the first threshold Belly of the whale The Hero’s Journey Return The ultimate boon Apotheosis Road of trials Tests and ordeals Dragon battle Nadir Crucifixion Symbolic death/dismemberment Sparagmos Meeting with the Goddess Atonement to recognition by Father © 2008–2012 Jouni Smed Initiation
  • A.J. Greimas: Actant model • first role-based analysis of narrative ‣ background: semantics and structuralist stance • formalization of Propp’s roles ‣ not for what they are but for what they do • the actant model can be instantiated by a (Cavazza & Pizzi, 2006) © 2008–2012 Jouni Smed specific semantic field
  • Generic actant model Object Sought-for person Helper Subject Antagonist © 2008–2012 Jouni Smed Dispatcher
  • Roland Barthes: Interpretative codes • ACT (action) ‣ generalization of narrative function ‣ action sequences ‣ background knowledge required for interpretation ‣ contextual knowledge © 2008–2012 Jouni Smed • REF (reference)
  • Interpretative codes (cont’d) • SYM (symbolic) ‣ major cultural objects that symbolic (e.g., money) • SEM (semantic) ‣ choice of words to narrative events ‣ items that should trigger interpretation ‣ cues for future events ‣ elements of mystery relevant to the story © 2008–2012 Jouni Smed • HER (hermeneutic)
  • Claude Bremond: Agent and patient • agent is responsible for the changes in the narrative universe ‣ voluntary or unintended ‣ types: influencer, improver, protector, frustrator • patient is influenced by the narrative actions • transient status: characters can alternate between the roles © 2008–2012 Jouni Smed ‣ awareness of the situation ‣ the situation itself
  • Brenda Laurel: Computers as Theatre • “When we look toward what is known about the nature of interaction, why not turn to those who manage it best – to those from the world of drama, of the stage, of the theatre?” (Laurel, 1991) ‣ designing an interface is the real problem ‣ creating a representational world that leaves the feeling of the interface behind © 2008–2012 Jouni Smed • invisibility of the computer
  • Material for action Material cause Thought Language Pattern Enactment User interaction Character Inferred formal cause Action © 2008–2012 Jouni Smed Neo-Aristotelian theory of interactive drama
  • The flying wedge of possibilities Potential Probable Potential t © 2008–2012 Jouni Smed Possible Necessary
  • Janet Murray: Hamlet on the Holodeck • can a computer provide the basis for an expressive narrative form? • Star Trek’s holodeck as an ideal model of © 2008–2012 Jouni Smed interactive narrative
  • Representational strategies (Murray, 1997) © 2008–2012 Jouni Smed • navigable space • encyclopedic capacity • participation • procedurality
  • Phenomenal categories (Murray, 1997) © 2008–2012 Jouni Smed • immersion • agency • transformation
  • Lessons from the holodeck: goals to pursue (Ryan, 2008) © 2008–2012 Jouni Smed • natural interface • integration of user actions within the story • frequent interaction • dynamic creation of the story • ability to create narrative immersion
  • Mapping and recapping the theoretical background 1(4) Aristotle’s Poetics Laurel: Computers as Theatre Mateas & Stern: Façade (Koenitz, 2010) © 2008–2012 Jouni Smed Carnagie Mellon: OZ project
  • Mapping and recapping the theoretical background 2(4) Derrida, Foucault, Barthes, Eco, Baudilard Storyspace platform Joyce: Afternoon Jackson: Patchwork Girl (Koenitz, 2010) © 2008–2012 Jouni Smed hyperfiction
  • Mapping and recapping the theoretical background 3(4) non-literary, non-western tradition (e.g., oral narratives) (Koenitz, 2010) © 2008–2012 Jouni Smed Jennings: the book of ruins and desire Harrell: Griot system
  • Mapping and recapping the theoretical background 4(4) Barthes, Bremond, Prince, Genette, Chapman narratology (Koenitz, 2010) © 2008–2012 Jouni Smed interactive fiction (IF)
  • © 2008–2012 Jouni Smed Strategies for interactive storytelling
  • Strategies • author-centric ‣ explicit authoring • character-centric © 2008–2012 Jouni Smed ‣ emergent narrative ‣ implicit creation
  • Measures • plot coherence ‣ the perception that the main events of a story are causally relevant to the outcome of the story • character believability (Riedl, 2004) © 2008–2012 Jouni Smed ‣ the perception that the events of a story are reasonably motivated by the beliefs, desires, and goals of the characters
  • Author-centric • models the creative process of a human author • explicit authoring: predefined template to • strong plot coherence • not so strong character believability © 2008–2012 Jouni Smed follow runtime
  • Example: The Oz Project’s Interactive Drama Engine Presentation Drama manager World Character Character © 2008–2012 Jouni Smed Player Character
  • Drama manager techniques • branching narrative • universal plan ‣ beats (i.e. action–reaction pairs) ‣ interactive plan trees (e.g. HTN) ‣ anticipation of every possible action ‣ combinatorial explosion (Louchart & Aylett, 2005) © 2008–2012 Jouni Smed • problems
  • Drama managers ways to influence (Crawford, 2005) © 2008–2012 Jouni Smed • environmental manipulation • goal injection • shifting personality • ticking clock of doom • dropping the fourth wall
  • Character-centric strategy • autonomous characters: models the mental factors that affect how characters act • the story emerges from the characters’ decisions and interaction • implicit creation: narrative planted • strong character believability • not so strong plot coherence © 2008–2012 Jouni Smed beforehand
  • Emergent narrative • term introduced by Aylett (1999) • story emerges bottom up based on characters described top down by the author © 2008–2012 Jouni Smed • exhibits perpetual novelty
  • Example: Reality TV • emergent narrative as a source for a story • participant ‣ motivated by money, fame etc. ‣ subjected to entertain the spectators ‣ gets entertainment ‣ lacks influence on the narrative © 2008–2012 Jouni Smed • spectator
  • Example: Reality TV (cont’d) • programme production team ‣ pre-production selections - choice and definition of the main protagonists - designing the world environment to foster emotions ‣ performance time control (Louchart & Aylett, 2005) © 2008–2012 Jouni Smed - tasks, eliminations etc. - compiling a broadcast to the spectators
  • Storyworld recepient designer Narrative interpretation Emergent system storyworld = mental model storyworld = model, rules world state → mental state world state → world state states, actions, events generating from the rules states, actions, events © 2008–2012 Jouni Smed reconstruct storyworld by inference (Spierling, 2007)
  • Gardening metaphor • author-centric ‣ explicit authoring is like creating a paper flower • character-centric ‣ implicit creation is like planting a flower © 2008–2012 Jouni Smed (Spierling, 2007)
  • © 2008–2012 Jouni Smed Characters
  • Features of believable agents • personality ‣ unique and specific, not general • emotion ‣ exhibit and respond personally-specifically • self-motivation • change ‣ growth and change with time (wrt. personality) © 2008–2012 Jouni Smed ‣ internal drives and desires
  • Features of believable agents (cont’d) • social relationship ‣ interaction with others changes the relationships • illusion of life (Mateas, 2002) © 2008–2012 Jouni Smed ‣ multiple goals ‣ broad capabilities ‣ quick reactions
  • Character behaviour 1. low level (e.g. collision detection) 2. social interaction (e.g. introducing oneself) 3. idle behaviour 4. targeted behaviour (i.e. go for the goal!) © 2008–2012 Jouni Smed (Fairclough & Cunningham, 2002)
  • Expressiveness • independent from visual realism • origins of expressive behaviour: ‣ agent itself ‣ human creator © 2008–2012 Jouni Smed (Szilas, 2007)
  • Flashback: Crawford on interaction… • “a cyclic process between two or more © 2008–2012 Jouni Smed active agents in which each agent alternately listens, thinks and speaks”
  • Character’s interaction • listen ‣ perception of the world • think • speak ‣ acting in the world © 2008–2012 Jouni Smed ‣ coloured by the character’s personality ‣ associated with and stored to the character’s memory
  • The perception system in VIBES 1. acquisition sensors: abstract description of the world 2. perception filters: simulation of the physical sensors (Sanchez et al., 2004) © 2008–2012 Jouni Smed 3. cognitive filters: support for the decisionmaking
  • Crawford’s personality model 1(2) Accordance Relationship Integrity “gullibility” “trust” Virtue “willingness to see good” “virtue perceived” Power “timidity” “fear of power” Intelligence “judging others wise” “respect” “vanity” “attractiveness perceived” Attractiveness © 2008–2012 Jouni Smed Intrinsic
  • Crawford’s personality model 2(2) Volatility Anger/Fear Adrenaline Joy/Sadness Manic/Depressive Arousal/Disgust Sensuality (Crawford, 2005) © 2008–2012 Jouni Smed Mood
  • Event-appraisal theory • OCC-model (Ortony, Clore and Collins) • emotional state ‣ positive/negative ‣ intensity objects varies according to their emotional state (Theune et al., 2004) © 2008–2012 Jouni Smed • agents reaction to events, actions and
  • OCC-model Directed to other agents hope – fear admiration – reproach joy – distress hope – fear pride – shame love – hate © 2008–2012 Jouni Smed Directed to agent itself
  • Autobiographical memory types • type 0: agent is always telling the same story • type I: agent has a variety of stories but not within the conversational context context best © 2008–2012 Jouni Smed • type II: agent selects a story that fits the
  • Autobiographical memory types (cont’d) • type III: agent tells and listens stories (i.e. interprets the meaning and has a response) • type IV: a living, autonomous agent (i.e. personality) © 2008–2012 Jouni Smed (Ibanez et al., 2003)
  • Memory in VIBES • stores information (i.e. percept objects) acquired about the world ‣ actor’s representation of the world ‣ knowledge the actor has acquired • records consecutive internal states of the (Sanchez et al., 2004) © 2008–2012 Jouni Smed actor (e.g. wants, emotions)
  • Memory in SAGA • narrative memory stores a temporal sequence of episodes ‣ cause-and-effect links between episodes ‣ crisis ‣ climax ‣ resolution (Machado et al., 2004) © 2008–2012 Jouni Smed • episode comprises
  • Episodic memory • personal history of an entity ‣ places and moments ‣ subjective feelings and goals • requires: persistent world and multiple actors scope (Brom et al., 2007) © 2008–2012 Jouni Smed • autobiographic memory: longer, lifetime
  • Requirements for a full episodic memory 1. storing complex hierarchical tasks 2. storing and reconstructing personal situations © 2008–2012 Jouni Smed ‣ what, with which and why? ‣ who saw and what did he do?
  • Full episodic memory (cont’d) 3. all available information is not stored ‣ perceivability ‣ importance ‣ attractiveness (or salience) 5. coherence: trust in the stored data (Brom et al., 2007) © 2008–2012 Jouni Smed 4. large time scale: the importance of forgetting (details reduced, events merged)
  • Late commitment • character agent’s decisions ‣ in-character (IC) ‣ out-of-character (OOC) • improvisational theatre: no agreed upon ‣ implicit OOC communication (e.g. “Hello, daughter.”) (Swartjes et al., 2008) © 2008–2012 Jouni Smed storyworld but framing as the actors go along
  • Late commitment (cont’d) • explicit OOC communication ‣ framing operators • late commitment (Swartjes et al., 2008) © 2008–2012 Jouni Smed ‣ goal management: goals from OOC if no other goals exist ‣ action selection: agents can create OOC plans for their goals
  • Late commitment: observations • IC actions should not be selected to satisfy the preconditions of framing operators • an action contradicting a framing operator has to be ordered after the framing operator • all characters must unconditionally accept (Swartjes et al., 2008) © 2008–2012 Jouni Smed all framing operators
  • Problem of believability: The uncanny valley • Masahiro Mori (1970): • the uncanny valley: the area of repulsion between “barely human” and “fully human” © 2008–2012 Jouni Smed ‣ the more human-like the robot, the more positive the emotional response ‣ at some point the response becomes quickly a strong repulsion ‣ as the appearance and motion improve, emotional response becomes positive again
  • The uncanny valley: Movement and appearance healthy person response + android/ gynoid industrial robot corpse/ zombie bunraku puppet prosthetic hand – 0% human-likeness 100%
  • © 2008–2012 Jouni Smed End-user
  • Affordance • interface design: opportunities for action made available by an object or interface • interface “cries out” for the action to be taken © 2008–2012 Jouni Smed (Mateas, 2002)
  • Choice problem • how to choose from a large amount of possible actions? © 2008–2012 Jouni Smed (Szilas, 2004)
  • Interface mapping function • P: physically possible actions f L • L: logically (in the story) possible actions ‣ real affordances © 2008–2012 Jouni Smed P ‣ perceived affordances
  • Interface mapping function (cont’d) • total ‣ non-surjective: filtering interface ‣ non-injective: redundant interface ‣ bijective: direct interface ‣ free interface: free interface © 2008–2012 Jouni Smed • partial
  • Anticipation of an action • author’s activity: plan the user’s inferences • stability: P and L should remain stable • surprise: counters stability ‣ new possibility should remain in the selection ‣ addition in slow pace ‣ freeze or fill in the time ‣ semi-autonomy ‣ ellipsis © 2008–2012 Jouni Smed • duration of interaction
  • User-centred actions • ethical consistency • motivational consistency • relevance (history) • cognitive load (opens/closes narrative processes) conflict) (Szilas et al., 2007) © 2008–2012 Jouni Smed • conflict (exhibits or pushes towards a
  • Inferring player states • inferring player’s knowledge • inferring player’s preferences • inferring player’s goals © 2008–2012 Jouni Smed (Thue et al., 2008)
  • The role of the end-user? • users probably do not want to be tragic or comic heroes • many users do not even want to be actors but marginally involved observers or confidantes (Ryan, 2008) © 2008–2012 Jouni Smed ‣ a peripheral character affecting the world and observing the outcome (i.e. agent and spectator)
  • Robin Laws: Seven player types 1. power gamer: new abilities and equipment 2. butt-kicker: fight! 3. tactician: thinking ahead 4. specialist: sticks with his favourite character 6. storyteller: plot threads 7. casual gamer: in the background © 2008–2012 Jouni Smed 5. method actor: want to test his personal traits
  • © 2008–2012 Jouni Smed Author
  • Author • authoring = delivering content for somebody else’s experience • author defines (Spierling, 2009; Spierling & Szilas, 2009) © 2008–2012 Jouni Smed ‣ actions ‣ states ‣ events
  • A contract with the author • there is a reason why the author is leading you through the story • how does that work in an interactive story? © 2008–2012 Jouni Smed (Perlin, 2005)
  • Narrative paradox and authoring • the author cannot expect the user to make the right decision at the right moment or in the right place • author’s role is to write interesting characters and rely on their ability to interact with one another user’s inner state (Louchart & Aylett, 2005) © 2008–2012 Jouni Smed • author must be extremely attentive to the
  • Second person insight • the ability to think in terms how the expression will be perceived by the audience © 2008–2012 Jouni Smed (Crawford, 2005)
  • Authoring challenges • authored content depends on the run-time system architecture • the increase in the amount of content • not a single author task © 2008–2012 Jouni Smed (Aylett et al., 2011)
  • Problems • finding IS authors ‣ reluctance to reduce human affairs into logical models • abstraction ‣ writing must be at the level of story-related abstract structures ‣ e.g., XML, Excel • algorithm-centered story design © 2008–2012 Jouni Smed • formatted and constrained writing
  • Problems (cont’d) • the potential of engines underused ‣ reduction to linear or branching structure ‣ no inspiring examples, lack of prototypes • authoring and programming intersecting (Spierling, 2009; Spierling & Szilas, 2009) © 2008–2012 Jouni Smed ‣ storyworld and engine have a blurry line ‣ immaturity of the medium
  • Boundaries of authoring end-user interaction author storyworld IS artefact IS experience developer (Spierling & Szilas, 2009) © 2008–2012 Jouni Smed runtime engine
  • Principles of design • main characters ‣ limit the number ‣ give clear relationships to one another within a dramatic situation • character definitions • parallel characters ‣ draw clear contrasts (e.g., rivals, friends, enemies) © 2008–2012 Jouni Smed ‣ along the spectrum based on the value system central to the story
  • Principles of design (cont’d) • characters as foils for one another ‣ emphasize similarities and differences • narrative events (Murray, 2011) © 2008–2012 Jouni Smed ‣ combine functions of an overarching frame story ‣ create coherent nested sequences
  • Potential influence abstract storyworld action selection action and behaviour models (Spierling, 2009) © 2008–2012 Jouni Smed staging / shape of events (representation) narrative discourse / sequence of events
  • Models of actions, states and events 1.possibility for action 2.actualization 3.result of the action • von Wright: logic of 3.state without the action • AI planning 1.pre-condition 2.action 3.post-condition (Spierling, 2009) action 1.intial state 2.end state after action © 2008–2012 Jouni Smed • Bremond: elementary sequence
  • Creative process of the author • debugging ‣ altering and adapting the story content to match the authorial intent • co-creation (Swartjes & Theune, 2009) © 2008–2012 Jouni Smed ‣ embracing the possible stories and letting it change the original authorial intent
  • Authoring types • content authoring ‣ which instances of story elements are in the domain? ‣ which actions, goals etc. may occur? • process authoring (Swartjes & Theune, 2009) © 2008–2012 Jouni Smed ‣ how do the element connect causally? ‣ when do the elements occur?
  • Iterative authoring 1. idea generation ‣ get inspired ‣ find flaws ‣ feel out the storyscape ‣ detect surprising behaviour 2. implementation ‣ add new content and processes ‣ constrain the domain (Swartjes & Theune, 2009) © 2008–2012 Jouni Smed 3. simulation
  • Principles of delayed authoring • AI in an IDS system is a decision-making proxy for the interactive story’s authors • delay story decisions made online: maximize the chance of new player information authoring process: it is better informed by inferred player information? (Thue et al., 2008) © 2008–2012 Jouni Smed • a story decision arising during the
  • Authoring in emergent narrative • interactive story ‣ who tells? ‣ to whom? ‣ what is the story? (Louchart et al., 2008) © 2008–2012 Jouni Smed • sender, receiver, message
  • Sender and message • sender ‣ narratorship shared between the system and the interactor • message © 2008–2012 Jouni Smed ‣ the interactor can construct their own message
  • Receiver • the notion of agency • not necessary to predict the consequences of an action • interactor can make choices they would • willingness to play within the role and its constraints © 2008–2012 Jouni Smed not do in real life (even if they know the consequences)
  • Landscape of possible stories • point: possible state • climbing hill: moving towards dramatic necessity (i.e., flying wedge) • valley: offers potential mountains © 2008–2012 Jouni Smed (Louchart et al., 2008)
  • Design suggestions (1)3 • justify the existing boundaries © 2008–2012 Jouni Smed ‣ spatial ‣ contextual ‣ interaction
  • Design suggestions (2)3 • critical mass for emergence ‣ density: how well the authored content serves to create different paths ‣ added content © 2008–2012 Jouni Smed - new possibilities - widens the boundaries and reduces density
  • Design suggestions (3)3 • dead ends ‣ narrative end = lack of content ‣ continuing process involving finding dead ends and resolving by adding new content © 2008–2012 Jouni Smed (Louchart et al., 2008)
  • Process of authoring • modelling a dramatic abstraction of reality ‣ how the characters behave (not how people are behaving in reality) • modelling implies complexity reduction ‣ too much generalization can lead to uninteresting stories plot (Louchart et al., 2008) © 2008–2012 Jouni Smed • author should not think in the terms of
  • • Improv: scripts • Hap/ABL: hierarchy of goals • FSMs/hierarchical FSMs • Motion Factory: graphical editors • Softimage • Virtools: flow charts • BEcool: oriented graphs (Szilas, 2007) © 2008–2012 Jouni Smed Authoring tools and methods
  • What does an author want? • testing ‣ debugging ‣ parameter tweaking ‣ replaying ‣ but what is actually the author’s role in interactive storytelling? © 2008–2012 Jouni Smed • feedback from the users • artistic control
  • © 2008–2012 Jouni Smed Systems
  • General scheme of an IS software 1. reasoning (decision-making, planning) 2. behaviour 3. animation (triggered by behaviour) © 2008–2012 Jouni Smed (Szilas, 2007)
  • Four-level story engine 1. story engine (flow of the story) ‣ narrative function the next scene should fulfil; gets story acts 2. scene action engine (play scene using a narrative function) 4. actor avatar engine (Spierling et al., 2002) © 2008–2012 Jouni Smed 3. character conversation engine (sends stage directions)
  • Four-level story engine (cont’d) axis: predefined – autonomous 1. strict – dynamically chosen scene 2. predefined scripts – generated scripts 3. dialogue – intelligent agent 4. stored animations – adapted animations © 2008–2012 Jouni Smed •
  • • CrossTalk • Façade • Interactive Drama Engine • Makebelieve • SAGA • Storytron • Virtual Storyteller © 2008–2012 Jouni Smed Reviewed systems
  • CrossTalk • interaction triangle: three screens ‣ virtual exhibition hostess ‣ changeable virtual exhibition visitors ‣ touch screen for the user’s choices © 2008–2012 Jouni Smed (Klesen et al., 2003)
  • Narrative structure vs. story content 1. scene flow definition 2. scene content creation © 2008–2012 Jouni Smed ‣ author’s scripts ‣ automatic dialogue generation
  • SceneManager • scene ‣ pieces of user-edited dialogue ‣ coherent and closed unit wrt. message, agent characterization or punchline • compound scene = linked atomic scenes • scene group = set of equivalent atomic • scene flow: narrative structure linking the scenes © 2008–2012 Jouni Smed scenes
  • SceneManager (cont’d) • scene node ‣ prescribed ‣ customically created ‣ interrupt ‣ conditional ‣ probabilistic © 2008–2012 Jouni Smed • scene transition
  • SceneManager (cont’d) • user input © 2008–2012 Jouni Smed ‣ request and wait ‣ time-out events ‣ interrupt (seamless interaction) ‣ concurrent event handling (affect long-term behaviour)
  • Dialogue strategies: plan operators © 2008–2012 Jouni Smed • context: goal and precondition • dialogue content • characters: role & personality • role & meta-role (trick for immersion)
  • Façade • story set-up ‣ player takes the role of a close friend of Trip and Grace, a couple whose relationship is in trouble ‣ events takes place at Trip’s and Grace’s home where the player is invited to have a cocktail ‣ moving and interacting in a 3D environment ‣ typing in utterances (Mateas, 2002; Mateas & Stern, 2004) © 2008–2012 Jouni Smed • player’s control
  • System structure • story comprises dozen carefully scripted interactive narrative scenelets • time is discretized into beats ‣ the smallest unit of a value change (i.e. an action– reaction pair) the relatively linear set pieces © 2008–2012 Jouni Smed • techniques to steer the narrative towards
  • Broad-and-shallow approach • idea inherited from the Oz project ‣ broad: all necessary features have an implementation ‣ shallow: some features could have been performed better necessary intelligently, in a wide range of situations © 2008–2012 Jouni Smed • characters can act believably, but not
  • Surface-text processing 1. map surface text into discourse acts © 2008–2012 Jouni Smed 2. map discourse acts into character responses
  • Discourse acts negative exclamation • express of emotion • unsure or indecisive • thank • greet • ally/oppose character • don’t understand • apologise • praise/criticize • flirt • pacify • explain • advice • refer to • ask to share intimate thoughts • say goodbye • miscellaneous discourse act • can’t understand © 2008–2012 Jouni Smed • agree/disagree • positive/
  • Interactive Drama Engine • prototype system ‣ non-linear narrative ‣ 3D characters ‣ graphical user-interface © 2008–2012 Jouni Smed (Szilas et al., 2007)
  • IDE architecture Narrative engine Narrative structure Action generation Action selection Behavioural engine Narrative GUI Game engine Player © 2008–2012 Jouni Smed Text generation
  • Makebelieve • virtual guide system, which uses ‣ Jess/CLIPS reasoning system ‣ OpenMind common sense data ‣ Unreal Tournament engine © 2008–2012 Jouni Smed (Ibanez et al., 2003)
  • Story element • name • type of event • location • attributes (nature of • special environment • basic concepts • subject: of the fact • object: of the fact (defined in knowledge base) • date • granularity: ‘size’ • effects: caused by this © 2008–2012 Jouni Smed the element) condition
  • Method 1. initial situation; input 2. select a story element 3. add related story elements (causation) 4. translate according to the guide’s attitude 5. consider common sense rules 7. generate storyboard © 2008–2012 Jouni Smed 6. extend story with common sense
  • SAGA • no predefined story • users interacting with autonomous character collaboratively play the role of the author • director: guide the accomplishment of a (Machado et al., 2004) © 2008–2012 Jouni Smed meaningful story
  • SAGA system • based on Propp’s narrative morphology • story definition ‣ initial story situation ‣ variable story schema goals → plan → hierarchy of goals and actions © 2008–2012 Jouni Smed • function → plot point → set of generic
  • Director agent 1. update situation 2. conflict? → select a new episode 3. current plot point achieved? → select the next plot point 5. new story element introduction needed? © 2008–2012 Jouni Smed 4. reflection event needed?
  • Storytron • components ‣ authoring tool SWAT ‣ storyworld library • launched 2006; discontinued 2011 • originally developed under the name (Crawford, 2005) © 2008–2012 Jouni Smed Erasmatron
  • Virtual Storyteller • multi-agent framework (Theune et al., 2004; Swartjes & Theune, 2006) © 2008–2012 Jouni Smed ‣ plot generation ‣ natural language generation ‣ presentation by an embodied agent
  • Plot generation • select “episodic script” from a database ‣ setting: location, characters,objects ‣ goals ‣ constraints before carrying out a plan © 2008–2012 Jouni Smed • character asks the director’s permission
  • Plot generation (cont’d) • within episode characters are free to choose action © 2008–2012 Jouni Smed ‣ subjected to probabilistic emotions (OCC-model) ‣ example: 90% fear means 0.9 probability of choosing a cowardly action
  • General transition model (GTN) ‣ G – goal ‣ A – action ‣ O – outcome ‣ E – event ‣ P – perception ‣ IE – internal event • causal relationships ‣ φ – physical causality ‣ m – motivation ‣ ψ – psychological causality ‣ e – enablement © 2008–2012 Jouni Smed • elements
  • GTN (cont’d) ψ IE φ/e E φ P ψ m G ψ m/e m A φ φ/e ψ O © 2008–2012 Jouni Smed ψ ψ
  • Decision-making in interactive storytelling • six general properties of story events • cf. the six questions in journalism ‣ who? what? when? where? why? how? © 2008–2012 Jouni Smed ‣ idea: what is the occurring action ‣ actors: who or what is acting or being acted upon ‣ time: when does the action occur ‣ place: where does the action occur ‣ actions: what changes ‣ reasons: why does the action occur (Thue et al., 2008)
  • Story decisions and design decisions story decision property design decision idea what should happen? result what was decided? actors who should be involved? chooser who made the decision? time when should it happen time when was the decision made? place where should it happen? — — actions how should it happen? method how was the decision made? reasons why should the actors act? justification why was the decision made in that way? © 2008–2012 Jouni Smed property
  • Story decision properties for Façade chooser time method justification idea author offline imagination no restrictions actors author offline imagination no restrictions follow dramatic principle / respond to player player & author online & offline place author offline imagination no restrictions actions player & author online & offline interruptible scripts allow player interactions reasons author offline imagination no restrictions © 2008–2012 Jouni Smed time tension arc / player interest
  • © 2008–2012 Jouni Smed Discussion and conclusion
  • Adaptation for interactive stories media • adaptation types ‣ scissors adaptation ‣ distilled adaptation ‣ expanded adaptation ‣ straight adaptation ‣ wild adaptation • adaptation in interactive storytelling: expanded or wild ‣ formalize the story into an abstract form ‣ make a creative interpretation and adaptation (Spierling & Hoffmann, 2010) © 2008–2012 Jouni Smed • translation between
  • Multiuser interactive storytelling • multiple users in application means handling conflicts ‣ intervowen stories that consistent, responsive and compelling ‣ solving the too-many-heroes problem ‣ maintaining persistency ‣ preventing cheating (Smed, 2011) © 2008–2012 Jouni Smed • challenges
  • Too many heroes • how to guarantee dramatically compelling story to everyone? • each human-controlled character needs a ‣ each new brings along extras ‣ limit the number of human-controlled characters © 2008–2012 Jouni Smed group of computer-controlled characters to support them
  • Persistency • how do we handle players entering and leaving at any time? ‣ user’s character vanishes from the storyworld ‣ user’s character becomes a computer-controlled character ‣ user can give tactical level instruction to character to follow during the absence © 2008–2012 Jouni Smed • when the user leaves the storyworld
  • Cheating • every action within the storyworld should be valid • limitations exist ‣ e.g. zombie attack and “I’ve been shot” in Façade ‣ is collusion cheating in an interactive story? © 2008–2012 Jouni Smed • how about multiple users?
  • Motivations for rereading interactive stories 1(3) • making sense of things ‣ new fragments to be reconciled into the overall understanding of the story • finding out more • trying out “what-if” scenarios ‣ different choices can lead to different outcomes © 2008–2012 Jouni Smed ‣ there is more to the story than can be seen on the surface
  • Motivations for rereading interactive stories 2(3) • seeing things from a different perspective ‣ radical revision of - player’s model of the storyworld - character’s personality and motivation - causal connections ‣ process of looking for an interpretation of the text © 2008–2012 Jouni Smed • looking for a deeper meaning
  • Motivations for rereading interactive stories 3(3) • reflecting on the techniques used ‣ appreciating or critiquing the ways in which the text achieves its effects • figuring out how the system works (Mitchell, 2010) © 2008–2012 Jouni Smed ‣ what is the underlying role system
  • Dramatis Personæ 1986–2002 Brenda Laurel Michael Mateas Andrew Stern Chris Crawford Janet Murray © 2008–2012 Jouni Smed Joseph Bates
  • Dramatis Personæ 2003– Stefan Göbel Ruth Aylett Sandy Louchart Ulrike Spierling Nicolas Szilas Ivo Swartjes Ana Paiva Mariët Theune © 2008–2012 Jouni Smed Marc Cavazza
  • References Ruth Aylett, "Narrative in virtual environments: Towards emergent narrative" in Papers from the 1999 AAAI Fall Symposium, Technical report FS-99-01, AAAAI Press, pp. 83–86, 1999. Ruth Aylett & Sandy Louchart, "Towards a narrative theory of virtual reality", Virtual Reality 7(1):2–9, 2003. Ruth Aylett & Sandy Louchart, "Being there: Participants and spectator in interactive narrative", in Cavazza & Donikian (eds.) Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. Proceedings of the Fourth International Conference, ICVS 2007, Lecture Notes in Computer Science vol. 4871, pp. 117–128, 2007. Ruth Aylett, Marco Vala, Pedro Sequeira & Ana Paiva, "FearNot! – An emergent narrative approach to virtual dramas for anti-bullying education", in Cavazza & Donikian (eds.) Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. Proceedings of the Fourth International Conference, ICVS 2007, Lecture Notes in Computer Science vol. 4871, pp. 202–205, 2007. Ruth Aylett, Sandy Louchart & Allan Weallans, “Research in interactive drama environments, role-play and story-telling”, in Si, Thue, André, Lester, Tanenbaum & Zammitto (eds.) Interactive Storytelling: 4th International Conference on Interactive Digital Storytelling, ICIDS 2011, Lecture Notes in Computer Science vol. 7069, pp. 1–12, 2011. Cyril Brom, Klára Pešková & Jiří Lukavský, "What does your actor remember? Towards characters with a full episodic memory", in Cavazza & Donikian (eds.) Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. Proceedings of the Fourth International Conference, ICVS 2007, Lecture Notes in Computer Science vol. 4871, pp. 89–101, 2007. © 2008–2012 Jouni Smed Selmer Bringsjord, "Is it possible to build dramatically compelling interactive digital entertainment?", Game Studies 1(1), 2001.
  • References (cont’d) Marc Cavazza & David Pizzi, "Narratology for interactive storytelling: A critical introduction", in Göbel, Malkewitz and Iurgel (eds.) Technologies for Interactive Digital Storytelling and Entertainment. Proceedings of the Third International Conference,TIDSE 2006, Lecture Notes in Computer Science vol. 4326, pp. 72–83, 2006. Chris Crawford, On Interactive Storytelling, New Riders, Berkeley, CA, USA, 2005. Chris Fairclough, Story Games and the OPIATE System, PhD thesis, University of Dublin, Trinity College, Dublin, Ireland, 2004. Chris Fairclough & Pádraig Cunningham, "An interactive story engine", in O'Neill, Sutcliffe, Ryan, Eaton & Griffith (eds.) Proceedings of the 13th Irish International Conference on Artificial Intelligence and Cognitive Science, Lecture Notes in Artificial Intelligence vol 2464, pp. 171– 176, 2002. Jesus Ibanez, Ruth Aylett & Rocio Ruiz-Rodarte,"Storytelling in virtual environments from a virtual guide perspective", Virtual Reality 7(1): 30–42, 2003. Martin Klesen, Michael Kipp, Patrick Gebhard & Thomas Rist, "Staging exhibitions: methods and tools for modelling narrative structure to produce interactive performances with virtual actors", Virtual Reality 7(1):17–29, 2003. Brenda Laurel, Computers as Theatre, Addison-Wesley, Reading, MA, USA, 1991. © 2008–2012 Jouni Smed Hartmut Koenitz, “Towards a theoretical framework for interactive digital narrative”, in Aylett, Lim, Louchart, Petta & Riedl (eds.) Interactive Storytelling: 3rd Joint Conference on Interactive Digital Storytelling, ICIDS 2010, Lecture Notes in Computer Science vol. 6432, pp. 176–185, 2010.
  • References (cont’d) Sandy Louchart and Ruth Aylett, "Managing a non-linear scenario – a narrative evolution", in Subsol (ed.) Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. Proceedings of the Third International Conference,VS 2005, Lecture Notes in Computer Science vol. 3805, pp. 148–157, 2005. Sandy Louchart, Ivo Swartjes, Michael Kriegel & Ruth Aylett, "Purposeful authoring for emergent narrative", in Spierling & Szilas (eds.) Interactive Storytelling. First Joint International Conference of Interactive Digital Storytelling, Lecture Notes in Computer Science vol. 5334, pp. 273–284, 2008. Isabel Machado, Paul Brna & Ana Paiva, "1, 2, 3... action! Directing real actors and virtual characters", in Göbel, Spierling, Hoffman, Iurgel, Schneider, Dechau and Feix (eds.) Technologies for Interactive Digital Storytelling and Entertainment. Proceedings of the Second International Conference,TIDSE 2004, Lecture Notes in Computer Science vol. 3105, pp. 36–41, 2004. Michael Mateas, Interactive Drama, Art and Artificial Intelligence, PhD thesis, Carnegie Mellon University, Pittsburgh, PA, USA, 2002. Michael Mateas & Andrew Stern, "Natural language understanding in Façade: Surface-text processing", in Göbel, Spierling, Hoffman, Iurgel, Schneider, Dechau and Feix (eds.) Technologies for Interactive Digital Storytelling and Entertainment. Proceedings of the Second International Conference,TIDSE 2004, Lecture Notes in Computer Science vol. 3105, pp. 3–13, 2004. Janet Murray, Hamlet on the Holodeck, MIT Press, Cambridge, MA, USA, 1997. © 2008–2012 Jouni Smed Alex Mitchell, “Motivations for rereading in interactive stories: a preliminary investigation”, in Aylett, Lim, Louchart, Petta & Riedl (eds.) Interactive Storytelling: 3rd Joint Conference on Interactive Digital Storytelling, ICIDS 2010, Lecture Notes in Computer Science vol. 6432, pp. 232–235, 2010.
  • References (cont’d) Janet Murray, “Why Paris needs Hector and Lancelot needs Mordred: Using traditional narrative roles and functions for dramatic compression in interactive narrative”, in Si, Thue, André, Lester, Tanenbaum & Zammitto (eds.) Interactive Storytelling: 4th International Conference on Interactive Digital Storytelling, ICIDS 2011, Lecture Notes in Computer Science vol. 7069, pp. 13–24, 2011. Federico Peinado & Pablo Gervás, "Automatic direction of interactive storytelling: formalizing the game master paradigm", in Cavazza & Donikian (eds.) Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. Proceedings of the Fourth International Conference, ICVS 2007, Lecture Notes in Computer Science vol. 4871, pp. 196–201, 2007. Ken Perlin, "Toward interactive narrative", in Subsol (ed.) Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. Proceedings of the Third International Conference,VS 2005, Lecture Notes in Computer Science vol. 3805, pp. 135–147, 2005. Vladimir Propp, Morphology of the Folktale, University of Texas Press, Austin, TX, USA, 1968. Mark O. Riedl, Narrative Generation: Balancing Plot and Character, PhD thesis, North Carolina State University, Raleigh, NC, USA, 2004. Marie-Laure Ryan, "Interactive narrative, plot types, and interpersonal relations", in Spierling & Szilas (eds.) Interactive Storytelling. First Joint International Conference of Interactive Digital Storytelling, Lecture Notes in Computer Science vol. 5334, pp. 6–13, 2008. Jouni Smed, “Once upon a time: The convergence of interactive storytelling and computer games”, in Cruz-Cunha, Carvalho & Tavares (eds.) Business,Technological and Social Dimensions of Computer Games: Multidisciplinary Developments, Information Science Reference, Hershey, PA, USA, pp. 115–123, 2011. © 2008–2012 Jouni Smed Stéphane Sanchez, Olivier Balet, Hervé Luga & Yves Duthen,"Autonomous virtual actors", in Göbel, Spierling, Hoffman, Iurgel, Schneider, Dechau and Feix (eds.) Technologies for Interactive Digital Storytelling and Entertainment. Proceedings of the Second International Conference, TIDSE 2004, Lecture Notes in Computer Science vol. 3105, pp. 68–78, 2004.
  • References (cont’d) Ulrike Spierling, "Editorial: Digital storytelling", Computers & Graphics 26(1):1–2, 2002. Ulrike Spierling, Dieter Grasbon, Norbert Braun & Ido Iurgel, "Setting the scene: playing digital director in interactive storytelling and creation", Computers & Graphics 26(1):31–44, 2002. Ulrike Spierling, "Adding aspects of 'implicit creation'' to the authoring process in interactive stories", in Cavazza & Donikian (eds.) Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. Proceedings of the Fourth International Conference, ICVS 2007, Lecture Notes in Computer Science vol. 4871, pp. 13–25, 2007. Ulrike Spierling, "Conceiving interactive story events", in Iurgel, Zagalo & Petta (eds.) Interactive Storytelling. Second Joint International Conference of Interactive Digital Storytelling, ICIDS 2009, Lecture Notes in Computer Science vol. 5915, pp. 292–297, 2009. Ulrike Spierling & Nicolas Szilas, "Authoring issues beyond tools", in Iurgel, Zagalo & Petta (eds.) Interactive Storytelling. Second Joint International Conference of Interactive Digital Storytelling, ICIDS 2009, Lecture Notes in Computer Science vol. 5915, pp. 50–61, 2009. Ulrike Spierling & Steve Hoffmann, “Exploring narrative interpretation and adaptation for interactive story creation”, in Aylett, Lim, Louchart, Petta & Riedl (eds.) Interactive Storytelling: 3rd Joint Conference on Interactive Digital Storytelling, ICIDS 2010, Lecture Notes in Computer Science vol. 6432, pp. 50–61, 2010. Ivo Swartjes & Mariët Theune, "A fabula model for emergent narrative", in Göbel, Malkewitz and Iurgel (eds.) Technologies for Interactive Digital Storytelling and Entertainment. Proceedings of the Third International Conference,TIDSE 2006, Lecture Notes in Computer Science vol. 4326, pp. 49–60, 2006. © 2008–2012 Jouni Smed Andrew Stern, "Embracing the combinatorial explosion: A brief prescription for interactive story R&D", in Spierling & Szilas (eds.) Interactive Storytelling. First Joint International Conference of Interactive Digital Storytelling, Lecture Notes in Computer Science vol. 5334, pp. 1–5, 2008.
  • References (cont’d) Ivo Swartjes, Edze Kruizinga & Mariët Theune, "Let’s pretend I had a sword: Late commitment in emergent narrative", in Spierling & Szilas (eds.) Interactive Storytelling. First Joint International Conference of Interactive Digital Storytelling, Lecture Notes in Computer Science vol. 5334, pp. 230–241, 2008. Ivo Swartjes & Mariët Theune, "Iterative authoring using story generation feedback: Debugging or co-creation?", in Iurgel, Zagalo & Petta (eds.) Interactive Storytelling. Second Joint International Conference of Interactive Digital Storytelling, ICIDS 2009, Lecture Notes in Computer Science vol. 5915, pp. 62–73, 2009. Nicolas Szilas, "Stepping into the interactive drama", in Göbel, Spierling, Hoffman, Iurgel, Schneider, Dechau and Feix (eds.) Technologies for Interactive Digital Storytelling and Entertainment. Proceedings of the Second International Conference,TIDSE 2004, Lecture Notes in Computer Science vol. 3105, pp. 14–25, 2004. Nicolas Szilas, "BEcool: Towards author friendly behaviour engine", in Cavazza & Donikian (eds.) Virtual Storytelling. Using Virtual Reality Technologies for Storytelling. Proceedings of the Fourth International Conference, ICVS 2007, Lecture Notes in Computer Science vol. 4871, pp. 102–113, 2007. Nicolas Szilas, Jason Barles & Manolya Kavakli, "An implementation of real-time 3D interactive drama", Computers in Entertainment 5(1): 5, 2007. David Thue,Vadim Bulitko & Marcia Spetch, "Making stories player-specific: delayed authoring in interactive storytelling", in Spierling & Szilas (eds.) Interactive Storytelling. First Joint International Conference of Interactive Digital Storytelling, Lecture Notes in Computer Science vol. 5334, pp. 230–241, 2008. © 2008–2012 Jouni Smed Mariët Theune, Sander Rensen, Rieks op den Akker, Dirk Heylen & Anton Nijholt, "Emotional characters for automatic plot creation", in Göbel, Spierling, Hoffman, Iurgel, Schneider, Dechau and Feix (eds.) Technologies for Interactive Digital Storytelling and Entertainment. Proceedings of the Second International Conference,TIDSE 2004, Lecture Notes in Computer Science vol. 3105, pp. 95–100, 2004.