Situated Design of Virtual Worlds Using Rational Agents

Mary Lou Maher and Ning GuKey Centre of Design Computing and Cognition

University of Sydney

Designing Virtual Architecture

Definition: Virtual architecture comprises designed virtual places that support a broad range of human activities.

Current practice: create 3D models as place infrastructure with associated behaviors, predefined by designers.

Future: Dynamic and interactive virtual architecture that has physical architecture as roots but goes beyond static 3D modeling and construction.

Example Designs

Situated Design of Virtual Worlds

User-centred approach: dynamically designed and implemented as needed, and without the legacy of persistent infrastructure.

Rational agent (Wooldridge 2000).Virtual World Agent: each person/user has

an associated agent that negotiates and designs virtual worlds based on the current needs.

Foci of Various Agent Models

Reflex agent and utility agent (Russell and Norvig, 1995): a single agent and the reasoning processes involved.

Agent models of 3D virtual worlds (Maher and Gero, 2002): a society of agents, each agent is a component of a virtual world with an existing infrastructure.

Virtual world agent: performs situated design of virtual worlds for each user.

Components of the virtual world agent

UcVA Agent

Design Agent PartCommunication Agent Part

The virtual world agent interprets the world

Interprets sense data from the world:Sensation: from raw inputs to data for reasoning

and learning.Perception: finds patterns for developing the

agent’s concepts.Conception: assigns meaning to the patterns.

The virtual world agent changes the world

Reasons about changes to the world:Hypothesising: identifies the design goals for the

agent.Design: generates a design to achieve the design

goals.Action Activation: identifies the actions needed

to build the design.

?environment

percepts

actions

sensors

effectors

agent

Autonomous Agents

What the worldis like now

Condition-action rulesWhat action I

should do now

AgentSensors

Effectors

En

viron

men

t

Rational Agents

Virtual World Agent Model

Perception

Conception

Hypothesizer

Design

Sensors

Effectors

The World

Action

Agents as a Production System

Rules:PerceptionConception

HypothesizerDesignAction

Facts

Controller

Sensors

Effectors

A Shape Grammar Design Process

Shape grammar formalism (Stiny and Gips 1972, Knight 2000) is a descriptive and generative design language.

Shape rules: Replacement rules using the spatial forms of the designs.

Designs: generated by applying a sequence of shape rules.

Demonstration environment

Active Worlds (AW): a multi-user 3D virtual environment for hosting the virtual world.

Jess: a rule-based production system scripting language for implementing the knowledge core.

Meeting room scenario: represent a person in the virtual world with a UcVA Agent; UcVA agents reason about the dialogues of the avatars; the agents design and construct a meeting room when the avatars decide to have an online meeting.

Meeting Room Scenario

Sensation: assert raw data as facts to the working memory of the agent.

Perception: recognise the keyword “meeting”, and performs a count on the number of the avatars.

Conception: further look at the keyword and its relationships with other percepts like the number of the avatars.

Hypothesising: know the need of having a meeting for two avatars, set a goal to design a meeting room.

Generating Shape Rules Using An Existing Design

The CRC world: a virtual environment for collaborative research supporting meetings/seminars, conferences and exhibition/storage.

Analysis of the CRC world: generate shape rules that capture a specific CRC-World-like style.

Style: the common characteristics of using forms and representing functions.

Generating Shape Rules Using An Existing Design

Generate the plan:

Shape Rules Evolved from the CRC World Plan

Generate the plan: rule 1 and rule 2.

Rule 3 and rule 4.

Shape Rules Evolved from the CRC World Plan

Generate the plan : rule 5 and rule 6.

Rule 7 and rule 8.

Shape Rules Evolved from the CRC World Plan

Generate the plan : rule 9 and rule 10.

Apply rules: step 1 (rule 1 twice); step 2 (rule 3 once); step 3 (rule 2 four times); step 4 (rule 4, 5, 6 and 7 multiple times); step 5 (rule 8 once); step 6 (rule 9 twice); step 7 (rule 10 twice).

Generating the CRC World Plan by Applying Shape Rules

Initial Shape of the CRC world plan.

Generating the CRC World Plan by Applying Shape Rules

Step 1 towards the CRC world plan.

Generating the CRC World Plan by Applying Shape Rules

Step 2 towards the CRC world plan.

Generating the CRC World Plan by Applying Shape Rules

Step 3 towards the CRC world plan.

Generating the CRC World Plan by Applying Shape Rules

Step 4 towards the CRC world plan.

Generating the CRC World Plan by Applying Shape Rules

Step 5 towards the CRC world plan.

Generating the CRC World Plan by Applying Shape Rules

Step 6 towards the CRC world plan.

Generating the CRC World Plan by Applying Shape Rules

Step 7 towards the CRC world plan.

Generating the CRC World Plan by Applying Shape Rules

From initial shape to the CRC world plan.

Replacement Rules for Generating 3D Spatial Volumes

Replace 2D shapes with 3D units:

Replacement Rules for Generating 3D Spatial Volumes

Replace 2D shapes with 3D units:

Generating the CRC World Design by Applying Shape Rules

Generated form of the CRC world :

Generating Rules for Including Functional Objects

“Screen” objects for posting slides.“Sign” objects on the frame-like walls for

attaching web contents. A floating ring placed in the middle of the

room to focus the avatars’ attention for gathering purposes.

Rules for Placing Functional Objects

Constraints for Applying the Shape Rules

Initial shape: a 8m X 8m square. For less than 10 people: apply addition rules twice. For between 10 and 15 people: apply addition rules

three times. For between 15 to 20 people: apply additions rule

four times. Other shape operations: not affected.

Generating a New Design

Initial Shape

DesignState 1

DesignState 2

Rule 1

Conclusion

A design grammar can generate a very large design space with relatively few rules.

The design agent model can be used to generate player specific game environments of a specific style.

Interaction with other players can result in a combination of each players design grammar.