Interview mit Steve Polge (englisch)
Polge: AI is a vital to most games as a key mechanic for providing challenging and interesting situations and choices for players. Sometimes AI implementations unnecessarily try to address features that don't improve the experience, and often AI implementations fail to make the game as interesting and challenging for the player as they should have. By challenging, I don't mean hard, but rather engaging and though provoking, and not easily exploitable.
In terms of implementation, rather than provide a laundry list of features like path finding, obstacle avoidance, etc., I think it's more important to consider how the player will perceive the AI. The number one requirement for good AI is to never (or at least almost never) look stupid. Players will much more readily notice (and judge AI based on) recurrent examples of brain dead behavior, rather than occurrences of brilliant tactics. Certainly, players appreciate smart, unexpected, and emergent behavior, but only if it's reasonably obvious what's happening. To this end, it's vital that your NPCs provide a lot of feedback about what they are thinking and doing through speech and animation.
PC Games: How do you teach AI to act like a human?
Polge: The AI needs to understand the rules, strategy, and tactics of the game as well as a player of similar skill level would. It needs to have a knowledge model about the game world and game state that is similar in limitations to what a player would know. For FPS games, it's also very important for the AI to have a human-like aiming model, with the same kinds of strengths and weaknesses in hitting targets under various conditions that would affect a human player. These are three areas in which we believe we have made significant strides with UT3.
PC Games: What is the challenge in creating a good AI?
Polge: Successfully implementing all the features and capabilities I've described J. One important factor is prioritizing AI sufficiently, and early enough in the project, in the face of many other issues and features that are more immediate needs during the development of the game. It's also important to consider the AI implementation for the design of any game features with which the AI will interact. Many games seem to have AI whose development was rushed or tacked on late in development.
PC Games: Referring to pathfinding: Why do Bots/NPCs tend to get stuck in level architecture?
This is a difficult problem to solve perfectly when constrained by real-time performance requirements. Each generation of unreal game has certainly gotten much more robust in this respect.
PC Games: Where do you see the AI in 20 years?
Polge: It's hard to gaze into the crystal ball 20 years out, especially when one looks at how far we've come with games in the past 20 years. As AI gets better it allows us to explore new game scenarios and mechanics. For example, a game with a solid implementation of a robust speech recognition and synthesis as an interface, and a compelling personality and motivation model for NPCs could have game play focused on determining the motivations of allies and opponents.
PC Games: Do you remember moments where you were surprised by AI? Please describe positive
as well as negative situations.
Polge: When I first got the Darkwalker up and running, I was really surprised to see bots jump in and start really effectively sowing destruction and navigating around with it, even though I hadn't written any custom AI for the vehicle, and it had very different attributes than any other vehicle in the game. There have also been quite a few cases during development of what seemed like bots cheating turning out to be bots effectively exploiting bugs in the game.
PC Games: What is so special about AI in games Epic produces?
Polge: We have talented AI programmers with a good sense of game design. We develop our games with a schedule that allows for a long period of iteration and polish, and AI is regarded as a key feature throughout the development process.