Playing with Agents Agents in Social and Dramatic Games

1
Playing with Agents Agents in Social and
Dramatic Games

• Ana Paiva, et al.
• October 27, 2004

2
Agenda

• Introduction
• Synthetic Characters in Interactive Story Telling
• Roles of the agents
• Degrees of autonomy
• Degrees of control
• Some Applications
• Tristão and Isolda / Papous / Teatrix / FantasyA
  and SenToy
• Conclusions

3
Agents
Introduction

• Synthetic characters
• for virtual story-telling and games applications
• Capture the interest and attention of the user,
  providing dramatic experiences
• I think that we must know these fellows
  definitively before we can draw them - Walt
  Disney

Interactive story
Traditional linear story
Autonomous characters with a rich personality and
emotional states to respond to the users demands
4
Two Opposing Goals
Introduction

• Autonomy of the characters
• Have personality and emotions to generate
  believable situations
• Degrees of autonomy scripted, partially
  scripted, directed, constrained by role and
  autonomous
• Interactivity / User control
• Must be restricted to follow a certain narrative
  structure
• Degrees of control puppet-like control,
  guidance, influence, god-like control and no
  control

5
Roles of the agents
Synthetic Characters in Interactive Story Telling

• Story teller
• Uses emotional expressions, speech and gestures
  to convey the message in the story
• Character (Actor)
• Play roles and act out their stories
• Director
• Capture the state of the world (sensors),
  generates scripts for the synthetic actors
• Camera agent
• Perceives the virtual world and acts by moving,
  focusing, zooming, etc

6
Degrees of Autonomy (Scripted)
Synthetic Characters in Interactive Story Telling

• Scripted
• Characters do not have any autonomous behavior
• Simply follow a script provided by the programmer
  or the author
• All the possible actions must be considered in
  the script
• Partially scripted
• Some independent autonomous behavior
  (improvisational actions)
• Directed
• Follow a script given to them by a director
• Can change and adapt in real time

7
Degrees of Autonomy (Autonomous)
Synthetic Characters in Interactive Story Telling

• Constrained by role
• Characters perform autonomously constrained by
  the role they play in the story
• Autonomous
• Characters decide, according to the environment,
  which action to perform
• If things change, characters are able to adapt
  and respond appropriately
• Story will emerge from the actions of the
  characters

8
Degrees of Control
Synthetic Characters in Interactive Story Telling

• Puppet-like control
• User decides where and how to move, what to pick,
  etc.
• Guidance
• Giving directives on where to go, but not
  deciding how to go
• Influence
• Does not control the actions but influences
  certain aspects
• God-like control
• Does not apply specifically to the characters but
  rather to the environment
• No control

9
Tristão and Isolda
Some Applications

• Two synthetic dolphins
• Four types of emotions (pleased,displeased,
  passionate, frighten)can express to Isolda
• Does not control the actions ofthe dolphin, but
  only influencesits emotional state
• The developed system was composed of three
  functional modules
• Dynamic script-writer (mind module)
• Theatrical company (body module)
• Virtual stage manager (world module)

sensors
improvisation directives
multimedia meta commands
10
Papous
Some Applications

• Virtual story teller
• Controlled like a puppet by the story-writer
• Script with the markup elements (tags)
• The architecture of Papous
• Input manager (read text file)
• Environment control
• Deliberative module (mind of the character)
• Affective speech (voice of the character)
• Affective body expression (appearance of the
  character)

11
Teatrix
Some Applications

• Collaborative virtual environment forstory
  creation by young children
• Selecting scenes, characters, andprops in the
  story
• Roles in Teatrix
• Villain
• Hero/Heroine
• Magician
• Beloved one and family
• Donor (or provider)
• Actions of the characters are constrained by the
  roles they play

12
FantasyA and SenToy
Some Applications

• Computer game
• Characters are able to express emotionsby their
  behavior (their spells) eitheroffensive or
  defensive
• Happiness, sadness, fear, anger, gloat and
  surprise
• Each character decides what actionto perform
  according to internalemotion and opponents
  emotion
• Users control is achieved through SenToy

13
Conclusions

• Two aspects in the development of synthetic
  characters
• Autonomy
• User control
• Indeed, different applications and different
  types of interaction with the user lead to
  different approaches of characters autonomy