Earlier quoted context omitted.
PDF submissions are automatically substituted for scribd links.
I had wondered why everybody else at HN seemed to love that garbage. What a terrible misfeature.
Scribd is a Y Combinator investment.
The AI Systems of "Left 4 Dead" [pdf]
21–30 of 84 posts
Re: The AI Systems of "Left 4 Dead" [pdf]
#22Adjusting enemy spawn and behavior by a calculated 'emotional intensity' of the player - very nice.
Re: The AI Systems of "Left 4 Dead" [pdf]
#23Question about the navigation mesh. I'm assuming that represents an entire open area (otherwise the path optimization makes no sense) and the dark stuff are the obstacles. In that case I'm wondering how the arrive at the actual grids and arrows (slide 12)
This link explains fairly well how a navigation mesh may be automatically generated from the level geometry: http://udn.epicgames.com/Three/NavigationMeshReference.html . I believe it's also a good practice for the level designer to examine it manually and make any necessary corrections for sharp corners, narrow corridors, etc. As for the path, A* search is usually the name of the game for any kind of 2D pathfinding.…
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Re: The AI Systems of "Left 4 Dead" [pdf]
#24That's a very interesting read, even though in practice, the ingame AI still feels lackluster. Survivor bots often ignore nearby players attacked by special infected to move (slowly) towards some far away target (another attacked/incapacitated player) and special infected bots could really use some cooperation (as do many human players ...).
I always wished that I could tell the bot teammates "stick together", "fan out" or "help me" via the chat. That would give them an actual sense of social intelligence, and bring them closer to real players (to be 100% realistic they would then have to ask "where r u??" :)).
Oh man that would be so cool. I suppose if text based adventure games can "understand" meaning within text, there's no reason it couldn't be remodelled into a chat setting.
Re: The AI Systems of "Left 4 Dead" [pdf]
#25This is exactly the reason why I don't like playing computer games. The games feel really scripted. Enemy character that wait until I cross a line before they attack me etc. I wished that instead of investing in graphics, the AI got more attention.
In light of the recent post on intelligence being analogous to the maximization of entropy available for future choices, I think things will get a lot more interesting in the future. Skynet may not be far off... (Even if computers can't feel, they might be able to put up a good fight.) That said, I don't know how I would feel about game characters stalking me on Twitter for a few days before showing up unannounced at my in-game job... Sometimes it's nice to know it's a game. (To say nothing of the autonomous military applications.)
Re: The AI Systems of "Left 4 Dead" [pdf]
#26That's hardly AI. It's just algorithms. Parametrized, using a probability distribution to randomize the environment, user programmed algorithms. EDIT: Well, if this AI in game development, then so be it. But it's still not AI in the generic way, IMHO. To downvoters: I didn't contest the fact that they don't work. I do enjoy this games a lot and I praise the programmers that make such games work.
That's what "AI" usually means in the context of game development.
Thanks, I edited my comment. I am more in the field of general AI ( and the rest of pure definition of AI ). So normally what I saw is the intelligence of a programmer put into very clever algorithms. I don't see any learning effect , or persistence effect. In fact, once you shut down the game, it starts all over. I'd love a game that learns from the player ( like how to climb over an obstacle ). Or can anyone point me to such a game?
Re: The AI Systems of "Left 4 Dead" [pdf]
#27Earlier quoted context omitted.
That's what "AI" usually means in the context of game development.
Thanks, I edited my comment. I am more in the field of general AI ( and the rest of pure definition of AI ). So normally what I saw is the intelligence of a programmer put into very clever algorithms. I don't see any learning effect , or persistence effect. In fact, once you shut down the game, it starts all over. I'd love a game that learns from the player ( like how to climb over an obstacle ). Or can anyone point…
IIRC, there was a survival horror game that claimed to learn from and adapt to the player in order to provide a scarier experience (playing to the player's phobias and such). Not sure if that qualifies.
Re: The AI Systems of "Left 4 Dead" [pdf]
#28Question about the navigation mesh. I'm assuming that represents an entire open area (otherwise the path optimization makes no sense) and the dark stuff are the obstacles. In that case I'm wondering how the arrive at the actual grids and arrows (slide 12)
This link explains fairly well how a navigation mesh may be automatically generated from the level geometry: http://udn.epicgames.com/Three/NavigationMeshReference.html . I believe it's also a good practice for the level designer to examine it manually and make any necessary corrections for sharp corners, narrow corridors, etc. As for the path, A* search is usually the name of the game for any kind of 2D pathfinding.…
Yeah I couldn't make sense of the arrows but I only know AI from 2d and have 0 clue about 3d game development.
Most toy examples I know use an even square grid so I was wondering if I might be missing something there.
Either way thanks for the answer (same goes for the other posters who provided links)
Re: The AI Systems of "Left 4 Dead" [pdf]
#29That's hardly AI. It's just algorithms. Parametrized, using a probability distribution to randomize the environment, user programmed algorithms. EDIT: Well, if this AI in game development, then so be it. But it's still not AI in the generic way, IMHO. To downvoters: I didn't contest the fact that they don't work. I do enjoy this games a lot and I praise the programmers that make such games work.
Search algorithms (especially ones using heuristics such as A*) are squarely in the AI category (planning a sequence of actions).
From a broader perspective the entire question of "should these bots seem humanlike or act rational" is a typical AI question (think the 4 squares of AI definitions in R&N). In this example it is specifically of interest to find a path that is not the most rational but rather the most humanlike (well technically I suppose you could find a performance measure to judge humanlike and optimize that and it would be rational after all).