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Are Evolutionary Algorithms Suitable for Building AI in Games?

Alex J. Champandard on November 20, 2007

Last week’s developer discussion covered a controversial topic: the applicability of computational intelligence techniques in games, specifically neural networks. This week, the topic is genetic algorithms (GA) and evolutionary strategies.

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Evolutionary algorithms (EA) fall into the category of general optimization strategies, which can be used to find approximate solutions to problems given a measure of fitness. Approaches based on artificial evolution rarely perform as well as specific optimization techniques on known problems, but they tend to provide satisfactory solutions generally for reasonably-sized problems.

Modern game developers certainly uses specific optimization techniques heavily, in particular for character animation, evolutionary algorithms still haven’t found a regular place in the development process — including for game AI.

  • Are there simply too few problems in games for GA/EA to become widely applied?

  • Do you think applying GA/EA in game design and development requires a specific skillset?

  • Is the evolutionary approach less useful than specific optimization techniques that are already used?

Certainly, the independent game development scene seems less reluctant to apply EA/GA into gameplay and AI…

Be sure to contribute to the discussion by posting a comment below!

Discussion 1 Comments

rcparts on November 23rd, 2007

I have the same experience as Walker: it's very easy to implement GA. And, contrary to some comments, I think it could be very useful in games, as we can see in Nero: http://nn.cs.utexas.edu/NERO/about.html It's a kind of RTS game where the units evolve in real-time using genetic algorithms (combined with neural networks, resulting in the NEAT approach). Again, agreeing with Walker, I think that evolving monsters in MMOG's would be very cool (both AI and appearance), and I have already a project on it. Another approach would be to evolve entire stages/maps. The more difficult is it to the player to complete the stage -> more fitness it has (it's a form of competitive coevolution). So the difficult level would grow naturally.

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