1. Situated Design of Virtual Worlds Using Rational Agents Mary Lou Maher and Ning Gu Key Centre of Design Computing and Cognition University of Sydney

2. 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.

3. Example Designs

4. 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.

5. 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.

6. Components of the virtual world agent UcVA Agent Design Agent PartCommunication Agent Part

7. 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.

8. 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.

9. ? environment percepts actions sensors effectors agent Autonomous Agents

10. What the world is like now Condition-action rules What action I should do now Agent Sensors Effectors Environment Rational Agents

11. Virtual World Agent Model Perception Conception Hypothesizer Design Sensors Effectors The World Action

12. Agents as a Production System Rules: Perception Conception Hypothesizer Design Action Facts Controller Sensors Effectors

13. 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.

14. 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.

15. 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.

16. 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.

17. Generating Shape Rules Using An Existing Design  Generate the plan :

18. Shape Rules Evolved from the CRC World Plan  Generate the plan : rule 1 and rule 2.  Rule 3 and rule 4.

19. Shape Rules Evolved from the CRC World Plan  Generate the plan : rule 5 and rule 6.  Rule 7 and rule 8.

20. 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).

21. Generating the CRC World Plan by Applying Shape Rules  Initial Shape of the CRC world plan.

22. Generating the CRC World Plan by Applying Shape Rules  Step 1 towards the CRC world plan.

23. Generating the CRC World Plan by Applying Shape Rules  Step 2 towards the CRC world plan.

24. Generating the CRC World Plan by Applying Shape Rules  Step 3 towards the CRC world plan.

25. Generating the CRC World Plan by Applying Shape Rules  Step 4 towards the CRC world plan.

26. Generating the CRC World Plan by Applying Shape Rules  Step 5 towards the CRC world plan.

27. Generating the CRC World Plan by Applying Shape Rules  Step 6 towards the CRC world plan.

28. Generating the CRC World Plan by Applying Shape Rules  Step 7 towards the CRC world plan.

29. Generating the CRC World Plan by Applying Shape Rules  From initial shape to the CRC world plan.

30. Replacement Rules for Generating 3D Spatial Volumes  Replace 2D shapes with 3D units :

31. Replacement Rules for Generating 3D Spatial Volumes  Replace 2D shapes with 3D units :

32. Generating the CRC World Design by Applying Shape Rules  Generated form of the CRC world :

33. 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.

34. Rules for Placing Functional Objects

35. 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.

36. Generating a New Design Initial Shape Design State 1 Design State 2 Rule 1

37. 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.