1. Qualitative Spatial Analysis Part 2 Chris Mansley

2. FPS to RTS FPS environments are becoming more dynamic and simple path-finding is not enough to define movement Another place that can benefit from this type of higher level movement are strategy games

3. Terrain Analysis Strategy games often have large open spaces and valuable resources often with narrow passages between them It is often helpful to consider these as free spaces and connecting corridors

4. Terrain Analysis cont. Corridors can be considered one- dimensional entities that connect two free spaces The strategic value of the connection is strictly based on the way they connect free space

5. Master of Orion Turn Based Strategy Game Basic build empires game (in space) Colonization of different planets in different star systems

6. AI Goals To provide a measure of the strategic value of the star system Overall, the AI can then choose the best strategy Encourage border disputes

7. MOO3

9. Terrain Analysis Inside vs. Outside borders If all paths leading way from the system lead through one of our planets, its considered inside Threatened If not within borders or a path exists to another civilization without passing through one of our systems

10. Example 12 3 4 5 6 7 8 9

11. Selecting New Colonies Using the spatial data, star systems are selected Uses a series of modifiers to select the correct system to try and occupy If priorities are the same, square them and randomly select the best

12. Decision Start with 1.0 If we own planet at star system If enemy also has a planet there, multiply 1.5 Else, we own the system, multiply 0.8 If system is inside our borders, multiply 0.9 If outside and has enemy colony, multiply by 0.3 Etc…

13. Outcome By tweaking the modifiers, the AI gave a sense of strategy and borders Before using this type, AI would mingle with everyone, frustrating the player Use the analysis system, to select other factors like best target or defenses

14. Conclusion Reasoning about the game world by NPCs needs to be more than simple pathfinding Trying to formalize such qualitative concepts such as good strategies, best non-direct movement, or dynamic environment use, results in better game play for everyone

15. References AI Game Programming Wisdom 2 Forbus, K., “How Qualitative Spatial Reasoning Can Improve Strategy Game AIs”, IEEE Intelligent Systems, July/August 2002 Master of Orion 3, Quicksilver Software, Inc 2003