Halo 3: ODST made numerous bold design changes compared to its predecessors, in particular its open hub-world that's populated with enemy NPCs. During the promotion of the game, Bungie released a video documentary with insights from behind the scenes. For approximately 30 seconds during the video, you can see footage of the AI technology applied here. And, yes, some of the debug rendering for the waypoints seems to be pink!

In particular, during that short section, Bungie designer Alex Pfeiffer talks about the squad patrol behaviors that that's used to bring life to the city. Since Halo 3: ODST is a partly open-world game, new technology was needed to make sure there's always enemy presence within the hub — which could be adjusted up and down by the designers. You can watch the AI patrolling in the highlight below...

As games become more ubiquitous, two of the most important design challenges we face as developers are difficulty adaptation and experience management. Pure, a dirt racing title from Disney Interactive, received critical acclaim by addressing both of these issues.

In this presentation from the Paris Game AI Conference 2009, you'll hear from Eduardo Jiménez about how Black Rock designed their own "race script" solution as an alternative to rubber banding that increases the amount of interactions between the riders. You'll also see how this avoids the visible effects of speed-adjustment, and finally you'll discover how this was implemented in practice, both with videos from the game and a prototype mini-game.

Of all the game modes in Left 4 Dead, Survival has some of the most interesting dynamics from an AI perspective. From the initial concept, to survive as long as you can with help of your four buddies, the game mode quickly turns into a process of finding optimal locations in the map to defend...

Obviously, when there's a medal or achievement involved, this optimization process becomes particularly creative! What makes this interesting for the Zombie AI, is that the best locations are those that the infected horde has a hard time reaching... Cue unexpected results.

INVITATION: What are the next big challenges for Zombie AI? Join resident expert Phil Carlisle and your regular host Alex Champandard in a Halloween Special this weekend. The online presentation is open for anyone signed-up (free) to AiGameDev.com and will take place live on Sunday, November 1st. Details here.

AI is only as good as the information it gets; if garbage goes in, garbage comes out. Unfortunately, acquiring good information about the physical world around an actor is not a trivial task, and calculating things like collisions and line of sight queries can take a fair bit of processing power. Providing such an interface between the low-level collision representation is typically the role of a sensory system.

In this 1h30 masterclass, you'll discover the big picture that a programmer needs to know about sensory systems — using examples from Thief: Deadly Shadows. In particular, what information do they provide for the AI to reason with, and how do they create an interface between the AI and other systems? Then, focusing on the low-level, you'll find out what it takes to build a good sensory system that can scale up and down depending on the computation power available on your target platform, and most importantly how it can manage sensory queries efficiently.

As military-style games become bigger in scope and more realistic in their simulations, there's an increasing need for using AI to help generate mission scripts automatically under the supervision of designers. Furthermore, online services can be used to extend the lifespan of games by providing procedural missions for players on either standard maps or user-generated content.

In this presentation from the Paris Game AI Conference 2009, William van der Sterren presents his most recent project involving HTN planners based on A*. You'll discover how his web-server based implementation can plan intricate coordination for missions in Armed Assault (a.k.a. ArmA 1). You'll also learn the challenges of applying HTN and A* to making sure units behave in a sensible & tactical manner. You'll also find out what it takes to make military units of many different type coordinate together to achieve objectives.

Editor's Note: This coverage from IEEE Symposium on Computational Intelligence and Games 2009 was written by Luke Dicken. In particular, his article looks at some of the key research from the conference, and discusses the relationship between industry and academia as it came across during the event.

The IEEE Symposium on Computational Intelligence and Games (CIG) is a refreshing conference to my mind because you can put any three attendees in a room and get four different takes on what the conference is about. There are the Game Theorists, talking Nash Equilibria and mixed strategies (Hingston, 2009), the Serious Games people dealing with a more simulated what-if approach to the world — in scenarios such as Disaster Relief or Naval Strategy (Avery, Louis, & Avery, 2009). There are researchers working on a whole range of more classical board and card games such as Poker, Diplomacy or Risk (Kemmerling et al., 2009). And of course, there are the Video Game researchers — but even within this group there are further classifications to be made between those using games as a controlled environment in which to develop better AI techniques (Thompson & Levine, 2009), those using AI to push forward the use of technology in contemporary games (Galli, Loiacono, & Lanzi, 2009), and those using the marriage of advanced AI methodology with video games for some other end, such as behavioural modelling of players (Drachen, Canossa, & Yannakakis, 2009) or automated content creation (Tanimoto, Robison, & Fan, 2009).

Even within our own specific niche, our community remains very diverse. Not only diverse but also of a very high quality — it's hard to single out specific pieces of research to point to as being worth mentioning, because it almost certainly means excluding something else that deserves to be here. You can see the full proceedings here to make sure you don't miss anything. (Also see the bottom of this article for the full references from the previous paragraph!)

Your archers are engaging enemy cavalry from a distance using their ranged attack. The opposing forces harass you, the archers get a bit too complacent and move away from the protection of your infantry. Seeing the opportunity, the enemy cavalry charges suddenly! How do you make sure your archers or crossbowmen switch to their hand weapon to try to limit the damage?

Such problems come up very frequently in game AI. What do you need to do to make sure the AI can deal with changing its mind, for instance to switch between an attack that makes sense in one situation (e.g. ranged attack) vs. another attack mode that needs to be used otherwise (e.g. close combat)? How should you structure your behaviors to support such situations? This masterclass using examples from the indie game Mount & Blade to explain the solutions.

As more games strive for replayability and unique experiences, AI becomes increasingly important to help synthesize the gameplay and adapt to what the players are doing. This can help significantly increase the lifespan of single player games or story-based games, even if they are mostly linear like Left 4 Dead. With large open sandbox worlds, technologies like the AI Director become even more important to help make the experience a little less mediocre during the worst moments, since emergence is rarely good enough on its own!

This in-depth feature article looks into Left 4 Dead's procedural gameplay systems and the famous AI Director that helped Valve solve such problems, and secure the "Best Game AI of the Year" in the AiGameDev.com 2008 Awards. You'll learn how the zombie population is generated using a layered approach that's similar to Perlin noise, and how the results are adapted to what the players are doing. Dig into the a simple four-state system monitors and controls the whole experience, and discover what tricks Valve used to balance and tune the results.

The Paris Game AI Conference '09 that we organized four months ago brought together many experienced developers from industry and a majority of the middleware developers in Game AI — including our sponsors Spir.Ops, Havok, PathEngine, and Artificial Technology. It's thanks to the support from these great companies that we can work on raising the profile of Game AI throughout the community.

Since our event in Paris was open to all, there were also a fair share of students and beginners in the field of game AI. The second day concluded with a Take Away session for the attendees. I've already written my thoughts in the official report, but here you'll find the thoughts of one of the students at the conference... (See video below.)

Once again, I'd like to thank our Sponsors for their support, and among many other things, making such events possible. In this post you'll also find some links to interesting articles / pages for each of them.

Don't you hate it when your AI buddy runs straight into your line of fire? Doesn't it look even more stupid when enemies run through each other's line of fire while trying to approach you? These are the kinds of bugs that we've been able to solve using the current generation of console hardware, and particularly using multi-threading on the PS3.

This is the second article in the series about parallelism in KILLZONE 2's AI technology from the SPU perspective. The first article, about the use of cover maps to speed up combat calculations, can be found here. Both articles are based on a talk that Technical Director Michiel van der Leeuw gave at the Game Developers Conference '09. Here's how he framed this problem during his presentation:

“It's really annoying if everything's so scripted that people are constantly standing in your line of fire, or AIs standing in their own line of fire. It's a lot of work also to script the AI to avoid that; it makes for static situations. It doesn't work well with our realism we were after.”

In practice, Michiel points out that it can be quite a challenge to make the AI believable in dynamic situations. Such line of fire issues break all immersion. In the following article, you'll find out how Guerrilla Games fixed these problems using Jobs on the PS3's SPU.

I used to think of this site as a swan. What you see on the surface, including those many in-depth features and attentively formated articles, have that apparent elegance of a swan gliding over a lake. Under the water, what you don't see is little duck feet paddling like crazy. It used to be just me working full time on the blog, then my wife Petra joined and we launched small startup — and after that I took on a second shift ;-) These days, however, the best analogy is some kind of amphibian multiped with 10 or more limbs each pushing in the same direction. So if a swan is still an appropriate metaphor for our work on the site, it's more a half-mutant semi-robotic multi-legged swan that's gone much further than the pond we originally intended it to swim in!

What I'm trying to say is two fold: firstly, thanks for being a duck leg. This site wouldn't work without the passion that's palpable in this community, and frankly without it I probably wouldn't want to do this either. Secondly, things are changing fast and we're doing our best to cope! So bear with us. The Premium area means we'll be around as a small business as long as we don't do anything stupid, so you can understand why a lot of our efforts are focused on over-delivering every month; it helps make sure we can keep doing this full time. However, I realize that the blog right now isn't quite up to the high standards we set ourselves over the last few years, but we've been working on that...

Both the importance of AI and working conditions have changed quite dramatically over the past few years. What's it like to work as an AI programmer in big companies? How is being part of a small independent studio different? What should you expect from an average day of work?

In this 45 minute panel, you'll hear war stories from industry veterans about their time in industry, and learn about the current responsibilities of an AI programmer. You'll also find out what studios are looking for in developers, and how best to build yourself into the role of an AI programmer.

Participants: Phil Carlisle (British Indie), Eduardo Jimenez (Black Rock Studio), Mieszko Zielinski (People Can Fly)