Abstract

Games play an important role in the field of artificial intelligence (AI). They offer an environment to test ideas about human reasoning, problem solving and other human abilities. The ultimate goal of AI is to create an artificial man. Games offer the opportunity to create artificial players which are modeled after human beings. Playing the game, human beings can interact with these artificial creatures and experience how well these creatures show human-like behaviour.
Quake III Arena is a computer game that belongs to the genre of first person shoot-em up games. The player views from a first person perspective and moves around in a real-time 3D virtual world. The most important tasks are staying alive and eliminating opponents within this virtual world. These opponents are other people, equal in strength and abilities, connected to the same game through a network or the Internet. The game has a set of different virtual environments called levels or maps, that contain rooms and hallways. The players have a whole range of weapons, items and powerups available to aid in the battles that take place in these maps. Quake III Arena offers various ways to play the game including team based gameplay modes.
This thesis presents the Quake III Arena bot which is an intelligent artificial player emulating a human player in the game environment. This artificial player is often called a bot as an abbreviation for the word robot. With this bot everyone can enjoy the game and practice, without the need for a network connection to other people. The bot is an artificial player that only ‘ lives’ inside the computer, side by side with the game. The bot receives information about the game environment directly from the game program as a set of variables. The game input from the bot is also sent directly to the game program. Although the bot only ‘ lives’ inside the computer, the ingame behaviour of the bot has to be hard to distinguish from the behaviour of human players. To make the game more enjoyable and more versatile, a range of different bot characters is used that each play the game in their own style, and provide different challenges for the human player.
To show human-like behaviour a wide range of techniques and common sense solutions are used for the bot AI. The Quake III Arena bot is the first commercially developed artificial player that uses fully automated path and route finding through arbitrary complex 3D polygonal worlds, without the need for the bot to acquire knowledge about routing and navigation during gameplay. No human intervention is required to provide the bot with all the information needed to navigate through, and understand new game environments. The bot uses a volume (area) based representation of the 3D game environment, which serves as a back-bone for the bot’ s cognitive world model. Together with a high performance path finding solution this cognitive model makes the bot rather resource efficient.