Less A, More I: Putting More Intelligence Into Our AI
It was four years ago, but I remember it like it was yesterday. My first
video game artificial intelligence (AI). It was for a creature called the
chikkit. I had spent lots of time on the low-level AI of the game, implementing
a pathfinder, full vision and hearing, a system for passing messages and events
to the AI, and anything else the AI could possibly need. So I was really excited
to get started working on the actual AIs for the individual creatures. I went
into my office and coded and debugged until I finished the first version of the
AI. I was pretty happy with it, until people started coming into my office to
try it out. Invariably, the conversation would go something like this:
“Why isn’t that one attacking me?”
“It can’t see you.”
“Why not? I’m right in front of it!”
”Actually, the camera is right in front of it. You’re kind of off to the side a
ways, see?”
“Well, why’s that other one attacking me then? I came up behind it and it turned
around and hit me!”
“It heard your footsteps.”
“I don’t hear any footsteps.”
“Yeah, they’re pretty quiet, but someone marked the AI property for the sound as
‘LOUD’ in the editor, so the chikkits think they can hear them.”
“Why can’t the first one hear my footsteps?”
“The range of the sound is only fifteen feet, and that one’s about seventeen
feet away from you.”
So I worked and worked on the chikkits’ AI until they always attacked when
the player expected them to. And it turned out that the best solution didn’t
involve tweaking the chikkits’ field of view, or tuning their hearing. The best
solution was just to make the chikkits attack when the player was nearby,
because that was what was easiest for the player to understand.
What did I learn from this? It’s not necessarily the most advanced AI that’s
the most fun to play against. Sometimes simple behaviors are tons of fun. What
matters most is that the player can understand what the AI is trying to do, and
can learn how to respond to it. And if you focus more on what the player sees in
an AI than what’s intelligent, you end up with a better game.
That’s why I was really happy last year when I started working at inXile. Our
designers are very focused on making the game as fun as possible. Of course I
needed to implement some serious technology to do that—like a good pathfinder so
your party members don’t get lost—but in general we’ve focused on simple ways to
add new behaviors to the AI so that the enemies stay engaging and interesting
throughout the course of the game, without confusing the player.
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