Game AI Roundup Week #32 2008: 10 Stories, 1 Video, 2 Quotes

Novack on August 10, 2008

Weekends at are dedicated to rounding up smart links from the web relating to artificial intelligence and game development. As always, there are some good articles and blog posts for you to read. Remember, there’s also lots of great content to be found in the forums here! (All you have to do is introduce yourself.) Also don’t forget the recently launched Wiki, a great repository of knowledge about everything relating to artificial intelligence in games!

This post is brought to you mostly by Marcos Novacovsky (aka “Novack”). If you have any news or tips for next week, be sure to email them in to editors at Remember there’s a mini-blog over at (RSS) with game AI news from the web as it happens.

Video games and learning

Scott McLeod, in the blog site Dangerously Irrelevant, published an article where he address three ideas related to video games, schools, and learning: Individualization, simulation, and complexity. Here is a transcription, related to his view of the videogames AI:

The artificial intelligence engines that drive most video games are able to customize the learning experience for each individual player. In other words, the game you play is different than the game I play because we have different skills and knowledge and because we make different choices during the game. The gaming engine adjusts to our differences, providing each of us with a learning experience that is both unique and optimally challenging for us as individuals. That’s a pretty powerful argument for considering the use of video games in education.

Narrative Pacing

Dan Kline, AI and game programmer and designer who I use to quote on this column often, posted another interesting article on his blog Game of Design, the third of a series dedicated to procedural storytelling.

We can implement pacing in our games, and it doesn’t even need to be dynamic. The AI Director can help, but lots of games do it with tried-and-true fixed techniques. We do it naturally. Flow requires variation, and as we vary our designs, we increase our challenge. Diablo 2 did it with character levels. Super Mario Bros made its jumping puzzles familiar but harder. Halo steadily improved its AI and difficulty. Portal’s creators playtested the crap out of their product. All it requires is treating the player’s play experience like a unified entity, like a narrative experience, like a flow experience. Then you can bury narrative in your gameplay, the unified grail, if that’s what you’re searching for.

Design and game AI

Victor Epand posted in the site Au Pair an article entitled “The Benefits Of Artificial Intelligence In Computer Games”, on a view of the current state of the game AI, and its implications in design among other comments.

With artificially intelligent characters playing against you, it can mean that in some cases, even the game designers can’t entirely predict what the computers characters will do, and each game is likely to proceed a different way, depending on those responses.

Thoughts on Artificial Intelligence

In his blog The Cranky Crackpot, Timothy Roberts published an interesting post, where he puts fresh words to the old rant “bruteforce is not AI”, in relation to machines playing games.

The reason why a Grand-Master-beating computer freaked everyone out so much is that the computer and Gary Kasparov – unlike the calculator and the maths genius – were not playing the same game.

Kasparov was playing chess. The computer, however, was only playing ‘chess’. To all observers, ‘chess’ was indistinguishable from chess. There was a real chess board in the room, with real pieces. Every time the computer printed a move on the screen, the attendants would physically move the chess pieces on the board.

‘Chess’ also looked like chess because Kasparov was in the room, sweating, becoming increasingly agitated, and generally acting human. We are used to seeing human-like things interacting with human-like things. So, by inference, the spectators assumed that Kasparov’s opponent was also a human-like thing.

But in fact, for a computer, playing ‘chess’ is just like calculating pi: numbers are fed into an algorithm. The computer, in a sense, did not beat Kasparov at chess, because it was not playing chess at all. It was only playing ‘chess’.

Stargate Worlds AI Interview

MMORPG.COM interviewed Dan Elggrin, the Studio Head over at Stargate Worlds, in an interesting quick conversation about the AI that guides the actions of the upcoming MMOG hostile entities.

Stargate Worlds Studio Head Dan Dlggrin took the time recently to tell our own Jon Wood about the AI in the upcoming sci-fi MMO.

More fun with AI and Alice

Kryotech continues the series of posts dedicated to the programming of a simple game AI using Alice. This week, a bit of optimization and some new stuff, in two articles entitled “Reducing computing load in games made in Alice” and “New component for Alice game AI”.

So how do you keep the speed at a good rate? The answer is to activate the AI when it needs to be activated. Meaning that, start off the world with only a few AI’s running along with there health systems. We had mentioned before that the world variable could be very useful for other things besides just the retreat function in AI.

the AI can now retreat upon sensing it’s own damage. This is also an easier method, and the object variable can also be used for other things besides just AI

Testing the Limits of Single-Player

Jason Rohrer who has already been writing game design articles on The Escapist, this time approached his “Game Design Sketchbook” with a post about the Single-Player factor on a game re-playability, related with the AI.

modern single-player videogames, both fringe and mainstream, have almost completely abandoned AI as a game feature. Yes, enemies in most 3-D games are equipped with rudimentary path-finding, planning, and randomized behavior, but it’s nothing like what an AI does for Chess. These mainstream AIs are essentially trying to mimic believable human behavior, not provide an opponent with which you can explore the depths of the game mechanics.

Computer beats Go Pro Again

This time, Myungwan Kim was defeated at the U.S. Go Congress, and keeps the ball rolling on the race (and debate) toward machine vs man competitions.

“In a historic achievement, the MoGo computer program defeated Myungwan Kim 8P Thursday by 1.5 points in a 9-stone game. “It played really well,” said Kim, who estimated MoGo’s current strength at “two or maybe three dan,” though he noted that the program – which used 800 processors, at 4.7 Ghz, 15 Teraflops on borrowed supercomputers – “made some 5-dan moves,” like those in the lower right-hand corner, where Moyogo took advantage of a mistake by Kim to get an early lead. “I can’t tell you how amazing this is,” David Doshay — the SlugGo programmer who suggested the match — told the E-Journal after the game.”

Ray-tracing the way to go for game developers?

Intel keeps pushing his reasearch (and marketing machine) toward a Ray-tracing technology impulse on game development. Daniel Pohl engineer of the corporation, talked with Theo Valich from tgdaily, about the Larrabee.

“Another usage is for AI. In order to detect visibility from one player to another you can use rays to detect blocking objects. You can also use the visibility determination for pathfinding. It is interesting to note that the usage of rays for collision detection and AI is already used in some current games. But this is sometimes not done against the complete dynamic scene or it is done with only a few rays. From talking to game developers, we already got the feedback that they would also like to be able to spend more rays on those queries.”

Damian Isla Interview

Damian Isla, Bungie’s Lead AI Programmer, talked to about working independently from Microsoft, working on new IP, the progression of Halo’s AI and new gaming hardware.

What was the biggest change you saw in Halo’s AI - as it was when you joined, to as it is now?

Damian Isla: In a word: scale. Everything got bigger for Halo 3, with respect to Halo 1. More characters and also each of the characters has many more abilities and making that the experience of fighting along 15 marines who can do 50 things instead of five marines who can do five things - that’s a hard transition to make…

About AI and neural networks

In his blog Open game programming, Antti Salonen wrote an article on the AI side of his project, an Open Source game.

Encouraged by the theory and these practical tutorials, I went on translating Mat’s Minesweepers into Haskell. During this process I also realized why almost all of the tutorials and the theory of artificial neural networks didn’t show any practical examples; my neural network code itself is merely about 50 lines of active code and contains mostly just the mathematical formulas to the networks. The applicaton of neural networks, however, is nearing 200 lines of code (huge, isn’t it?) and basically describes the whole learning and using process of the brain, err, neural network.

Bungie On Eight Years Of Halo AI

During a recent programming keynote at the Develop conference in Brighton, Bungie’s Damian Isla (this guy is a very active person) framed the “30 seconds of fun” model in terms of AI, and shared with the audience a number of AI development stories drawn from throughout the series.

“I would guess that it’s one of the most sophisticated AI systems out there,” said Isla of his studio’s work on Halo. But he then noted that the series’ AI is not so much an attempt to create a true artificial intelligence as it is a system to facilitate “a player experience,” an experience that has been under “constant revision.”

That experience hinges on the “30 seconds of fun” — the notion that you can put “200 or 300 of these experiences laid back to back and you can make a game out of that.”


“In Halo 2, it was attempted to be solved behaviorally (“It was not pretty,” conceded Isla). In Halo 3, the team created “concepts” for territories or objects that require interaction; these concepts holds the knowledge of what a character will do with that thing. So, rather than having behavior determine how the NPC interacts with that vehicle, the vehicle contains all that interaction knowledge.”

Total AI

Another interesting Gamasutra interview, this time to the Creative Assembly’s Sutherns, about the Total War franchise. Some comments on the game’s AI are quoted below.

How do you build the AI to work with that? Obviously, AI is born to lose, but where is the balance between making it too stupid? Obviously you don’t want it to react exactly the same every time.

MS: No, and we’ve got a system in place to make sure that the AI is selecting the right tactics and the right “plays,” if you like, at the right time. We’ve got various diagnostic tools to make that possible, where we can put the AI, come in in the morning, and it’s fought a hundred battles. And it shows us the results of those battles; and it shows us the tactics it’s used; and it shows us how it’s fared against certain other tactics…

Discussion 1 Comments

Hodgman on August 12th, 2008

Re: "In order to detect visibility from one player to another you can use rays to detect blocking objects." You can also use rasterization, but I don't see them mentioning existing GPU occlusion queries.

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