Split-Screen :: The Game-Geek’s Daily Read

Valve Software recently published the slides of Michael Booth’s presentation at Stanford’s recent Artificial Intelligence and Interactive Digital Entertainment Conference, wherein he talks about the AI systems of their FPS co-op hit Left4Dead.

Booth outlined the 4 main goals of Left4Dead’s AI, such as

- Deliver Robust Behavior Performances
- Provide Competent Human Player Proxies
- Promote Replayability
- Generate Dramatic Game Pacing

He describes why the team went with Reactive Path Following against Path Optimization, where the latter has a more direct and clean path but the former taxes the CPU less. Interestingly, the downside of choosing the same, which includes “Can avoid off path too much, requiring repath” was outlined and more often than not can be seen in the final game. Booth also talks of the AI Director, and how it promotes replayability in the offline mode. You can check out the full presentation here.