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The AI Systems of "Left 4 Dead" [pdf]

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Re: The AI Systems of "Left 4 Dead" [pdf]

#61

Post by Fargren »

freehunter wrote: post #49
Extigy wrote: post #24

Earlier quoted context omitted.

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.

There are plenty of FPS games with AI that you can control with commands. The Rainbow Six games all have this, and if I'm not mistaken, I believe Counter Strike's bots can be controlled with commands as well.

Quake III's AI not only receives but also gives commands by chat. If you enter a team full of bots, you can see them talk to each other and "plan" to a certain extent.

Re: The AI Systems of "Left 4 Dead" [pdf]

#62

Post by jnazario »

kaoD wrote: post #55
jnazario wrote: post #48

in the past few months i started to learn a little bit about AI, including algorithms in planning (like PDDL) and logic engines. the more i learned the more i saw what the gaming companies, and that entire community, are doing and how they are some of the biggest consumers of these technologies. i have to say that it's impressed me, and it seems like the gaming companies are on the forefront of multiple areas of tech…

Woah, I've been doing the same thing for the past few months because I took an AI branch for my last year in college. Unfortunately I feel they've been teaching us mostly outdated and useless algorithms (with all due respect). I wish I was taught more about neural networks, machine learning, data mining techniques... and less about classic (and failed) AI algorithms. The most I learnt about these techniques was from…

no, i'm not a student.

presentations and papers like this are what i'm referring to:

https://skatgame.net/mburo/icaps2010-pg/ICAPS-PG.2010.1.bart...

http://www.plg.inf.uc3m.es/icaps-pg2007/papers/Symbolic%20Ex...

http://www.slideshare.net/StavrosVassos/the-simplefps-planni...

http://abotea.rsise.anu.edu.au/data/offline-htn-planning.pdf

http://www.guerrilla-games.com/presentations/VUA07_Verweij_H...

etc etc etc. turns out a lot of these ideas people thought were failures are getting a new lease on life in games, and they're working pretty well.

curious what classic AI algorithms you think are failing. from where i sit i'm seeing them get a new lease on life. maybe it's just the natural cycle of things: they get hot and invested in, they then fail to live up to their assumed potential, they fall out of favor for a while, and when everyone who was familiar with them - and their shortcomings - is gone a new generation finds it again and starts the cycle over.

Re: The AI Systems of "Left 4 Dead" [pdf]

#63

Post by ccozan »

setrofim_ wrote: post #47
galaktor wrote: post #42

Earlier quoted context omitted.

Exactly, AI in games solves a different problem than "traditional" AI. It's merely about creating the illusion of intelligence. Not unlike what happens in rigid body dynamics (approximated, not actual physics sim), graphics (plenty of tricks here, e.g. displacement maps vs actual geometry), animation (e.g. blending canned animations).

One could argue that "traditional" AI is also about creating the "illusion" of intelligence. That is what the Turing test is testing -- whether the illusion is sufficiently good to fool the tester into thinking that they're communicating with something intelligent. The difference is in the degree to which the illusion has to hold up. Game "AI" exist in a limited, artificial world; so they can get away with "simple" a…

Thanks for clarifications. I couldn't say it better.

In a real world, you can't live on illusions, an AI really needs to perform ( think Googles self running cars ). Learning ( and all the other useful ingredients of the AI ) are essential.

Re: The AI Systems of "Left 4 Dead" [pdf]

#64

Post by alan_cx »

robotmay wrote: post #33
arethuza wrote: post #12

Earlier quoted context omitted.

I only ever play multiplayer (mostly Halo 4 these days) - any time I try Campaign I find the AI rather boring and predictable. I don't know if the Halo series are bad for this or not.

Yeah, it's not anything amazing from my experience. I've heard the FEAR games had decent AI, as well as Far Cry. If we're not talking FPS then I've been impressed by the AI in XCOM. God damn those bastards are hard work.

I have heard that about Far Cry too, but even as a fan of all of the FC games, I really cant see why people say that. I'm not saying the AI is bad or sub par, just that I'm ignorant!!! To be fair though, I don't play that many games, so I don't really have much to compare to.

Re: The AI Systems of "Left 4 Dead" [pdf]

#65

Post by Nursie »

freehunter wrote: post #49
Extigy wrote: post #24

Earlier quoted context omitted.

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.

There are plenty of FPS games with AI that you can control with commands. The Rainbow Six games all have this, and if I'm not mistaken, I believe Counter Strike's bots can be controlled with commands as well.

SOCOM (going back to the PS2) had voice commands for your team via the headset.

Re: The AI Systems of "Left 4 Dead" [pdf]

#66

Post by Dove »

manmal wrote: post #10
lazyjones wrote: post #3

That'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??" :)).

When Left 4 Dead first came out, one of the features they were proud of was a radial mouse menu of chat commands. You could make your character say "Heal me!" or "Tank!" or really any of about 27 things. I think it was intended so players could communicate without breaking character . . . which turned out not to be a high priority. I can't remember seeing anyone use it in a live game.

Anyway, I always thought the bots should respond to those commands, and was always surprised when they didn't.

Then again, the experience with the commandable AIs in Half Life was so profoundly miserable, I thought maybe they couldn't get it working reasonably. After all, when you give a command to a human, there are a lot of contextual clues involved in how to interpret it.

Re: The AI Systems of "Left 4 Dead" [pdf]

#67

Post by illicium »

solnyshok wrote: post #36

If a SurvivorBot ever gets far out of place for any reason, it is teleported near the team when no human is looking at it (AI cheating algoritm!!! Really enjoyed that)

This works as long as the player doesn't notice. Counterexample: the Watson NPC in the Sherlock Holmes Nemesis game, http://youtu.be/13YlEPwOfmk

Re: The AI Systems of "Left 4 Dead" [pdf]

#68

Post by ahelwer »

afreak wrote: post #54
danso wrote: post #40

I love this game, one of the last FPSes I still play other than Team Fortress 2...unfortunately, like TF2, it's not very playable unless everyone in the round is amenable to being a team player. The multiplayer deathmatch allows one team to take the role of monsters, who have the backing of the zombie horde to make up for lack of guns. Playing it really provides some interesting insights to how the AI effectively fun…

> like TF2, it's not very playable unless everyone in the round is amenable to being a team player Amen. TF2 and L4D are two games that I consistently play years after the fact which is unlike other games I have. Unless you're playing with people you know, both games are equally frustrating. Specifically in TF2, it's those who go and play support classes when there are already enough of those in play on the map on yo…

That only matters if you care about winning.

TF2 also has a huge accessibility problem which contributes to an overabundance of support class players, but also makes it a brilliant game. As opposed to the Battlefield series, where seeing the enemy first is most of the battle, it's actually difficult to inflict any damage at all in TF2. For instance, I'm at about the 200 hour mark and when I play demo I can only hit ground-based targets with pipes maybe 20-30% of the time - and that's quite good! For beginners, the only playable frontline classes are pyro and heavy. Spy and sniper are also popular because it's easier to survive when playing them, and maybe sneak a few insta-kills. Medic is easy to play, but can be very boring.

tl;dr: Don't hate the player, hate the game. And don't hate the game, because you'd be hating what makes TF2 such a wonderful game to play. Even at professional levels getting an airshot is a remarkable feat.

Re: The AI Systems of "Left 4 Dead" [pdf]

#69

Post by qznc »

Fargren wrote: post #61
freehunter wrote: post #49

Earlier quoted context omitted.

There are plenty of FPS games with AI that you can control with commands. The Rainbow Six games all have this, and if I'm not mistaken, I believe Counter Strike's bots can be controlled with commands as well.

Quake III's AI not only receives but also gives commands by chat. If you enter a team full of bots, you can see them talk to each other and "plan" to a certain extent.

"Daemia patrol from quad to bfg for 3 minutes" ;)

http://www.angelfire.com/linux/vmerchand/quake.htm

Re: The AI Systems of "Left 4 Dead" [pdf]

#70

Post by Brashman »

TheMakeA wrote: post #35

Valve is (was) very open with their publications. There are more available on their website[1]. I definitely recommend taking a little time to look through them. [1] http://www.valvesoftware.com/publications.html

Any idea why there hasn't been anything since 2009? Have they stopped publishing/presenting or just not updated the site?
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