© 2004 Team Bondi Pty. Ltd. Interactive Drama – Dynamic Dialogue and Sandbox Worlds / AGDC.


Jason HutchensAI Team Lead – Team Bondi


Interactive DramaDynamic Dialogue and Sandbox Worlds


ABOUT ME

Research in Grammatical Inference and Data Compression.

Worked at Lionhead Studios on Black & White.

Former “Chief Scientist” of Artificial Intelligence Inc. in Israel.

Recently joined Team Bondi as AI Team Lead.


BLACK & WHITE


SCOPE

No State Machines, Scripting, A* or Flocking.

Use AI to create a dramatic experience for the player.

What can be achieved on Sony's next-gen console?


ARTIFICIAL INTELLIGENCE

A contentious term. Slippery to define

Turing un-asked the question “what is intelligence” via his Test.

We're specifically interested in behaviour that appears intelligent.


INFORMATION THEORY

Intelligent behaviour is unpredictable yet relevant.

Eliminate randomness and repetition – maintain reasonable surprise.

Behaviourism predicts the “slot machine” phenomenon.


EXAMPLE

Stochastic language models generate unpredictable sentences:

MegaHAL: WITHIN MY PENGUIN LIES A TORRID STORY OF HATE AND LOVE.

Keyword-based generation helps to make them relevant.

User: In 1793 the french king was executed.

MegaHAL: HA HA! CORRECT. ALTHOUGH, EXECUTED HAS MULTIPLE MEANINGS.

Users talk to this thing for hours on end, and respond emotionally.


SANDBOX WORLDS

Graphics got fast and detailed, so players wanted more interaction.

Physics improved, and is now practically mandatory.

It's fun to “muck around” within these “sandbox worlds”.

AI required to populate the world with believable characters.


INTERACTIVE DRAMA

All the world's a stage – add a compelling story to the mix.

Façade, by Mateas and Stern, is an example (InteractiveStory.net).

Dialogue is a necessary component.

AI required to present the story, and process the dialogue.


AUDIENCE OR PROTAGONIST?

Cut-scenes are non-interactive and quickly become repetitive.

Sandbox worlds lack dramatic tension.

Rather than “being” the protagonist, the player may “act” in their role.

AI required to interpret player action with respect to its context.


GAME AI

Typically, only 5% of resources spent on AI.

We'll soon have the power of a desktop PC of the early 1990's.

Create a compelling experience on such technology.

We need to look beyond the search-and-optimise of GOFAI.


SUMMARY

AI is required to populate the world with believable characters.

AI is required to present the story.

AI is required to process the dialogue.

AI is required to interpret player action.


THE CHALLENGE


ARCHITECTURE


PLAYER MODEL


PLAYER MODEL

Requirement: Interpret player action.

Goal: Balance player freedom with narrative consistency.

Goal: Enable cinematic presentation of gameplay sequences.

Abstracted commands – context provided by story, world and subject.


DIALOGUE ENGINE


DIALOGUE ENGINE

Requirement: Process the dialogue.

Goal: Ubiquitous, believable conversations.

Voice acting, localisation and input devices limit the possibilities.

Move beyond menu-based conversation and “taunts”.


DIALOGUE ENGINE

Adopt Mann's “Dialogue Macrogame Theory”.

A conversation is a sequence of short dialogue games.

Players take turns speaking, and negotiate game entry and exit.

Dialogue Engine moderates the games, and issues potential actions.


DRAMA MANAGER


DRAMA MANAGER

Requirement: Present the story.

Goal: Select a story thread and direct other components.

Provide potential dialogue games to the Dialogue Engine.

Constrain the behaviour of the Player Model and the Cast.

Inform the Camera, etc.


STORY ENGINE


STORY ENGINE

Requirement: Present the story.

Goal: Provide potential story threads to the Drama Manager.

Story threads specify cast, dialogue, locations, props, etc.

Story Engine selects relevant story threads opportunistically.

Each thread is a network of potential dramatic moments, or “beats”.


CAST MANAGER


CAST MANAGER

Requirement: Populate the world with believable characters.

Goal: A world of 1.5 million inhabitants.

Goal: Embodied, autonomous, reactive and conversational NPCs.

“Extras” provide background, and ad lib when necessary.

“Heroes” participate in the overarching story.


CAST MANAGER

NPCs have personality, emotion and a hierarchy of relationships.

Extras are spawned at “random”, according to demographics.

Extras behave reactively, foraging the environment and exiting ASAP.

Heroes are hand-crafted, and inhabit the world persistently.

Heroes behave deliberatively, as specified by story and routine.


WORLD MODEL


WORLD MODEL

Provide world knowledge to Story Engine and Cast Manager.

Manage non-story events that occur throughout the world.

Provide appropriate dialogue games for talking about them.


WORLD MODEL

Adopt Milgram's “Six Degrees of Separation”.

A “grapevine” extends from the NPC to an item of world knowledge.

Probability of existence may be estimated.

Each NPC appears to have their own knowledge of the world.


CONCLUSION

Suspension of disbelief requires believable worlds.

Technology only worth using if it enhances the player's experience.

We have the resources to build an AI team to achieve them.

And the opportunity to create a groundbreaking, immersive game.

[email protected]

© 2004 Team Bondi Pty. Ltd. Interactive Drama – Dynamic Dialogue and Sandbox Worlds / AGDC.

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Transcript of © 2004 Team Bondi Pty. Ltd. Interactive Drama – Dynamic Dialogue and Sandbox Worlds / AGDC.