What is Convincing AI Behaviour?

I've been working on AI a bit lately, and it's obviously been making me question what I consider convincing AI behaviour. Taking something basic like a FPS as the genre, because it's something most people will have played at some time, and because combative games are generally a good place for good AI, what did behaviour did you find convincing?

For example, in F.E.A.R. enemies would work together, one pinning you down with suppressing fire while another tried to flank you. Equally, if you tried to flank them, they'd spot it and warn their teammates. That stands out to me as great AI, at least when it works. When you're trying to run away and they think you're flanking them, it's a bit duff, but AI is never perfect.

What behaviours or features of FPS AI have you found convincing?

I find that when enemies are shot at and they run and try to regroup with more of their own. Also, when AI try to lead you into a trap. Can't remember the game, but there was this lone soilder/alien thing. I ran down the collidor after it in pursuit, and from each side of me i was ambushed :-O Cheeky buggers :o)

It's a hard one though... i suppose you could have different armies/squads, with their own tactics they like to use.

One thing that does annoy me, is when an enemy is hiding, and because the game "thinks" it can't be seen, doesn't seem to react to being shot. Like most humans, you'd be crappin yerself if someone was shoting at you. Especially if you got hit.

I've never actually played a game where I was lead into a trap and ambushed, I don't think. That would certainly be convincing to me.

Good point about the getting shot while hiding thing. In the same way that little behaviours can make good AI seem great, little errors can also make good AI seem terrible.

hehe, man I remember a room in doom 3 where if you snuck through the door and looked to the right hand corner there woudl be a zombie facing the corner trying to walk through the wall. He wouldn't react to you till you were mostly through the door.

Fear actually tricked me the way Ross described, not sure whether it was just a fluke though. I'd like to see more ambient AI in games.

Not sure if thats the right word, but just simple ambient behaviours and reactions that don't have much to do with anything gameplay related. Kind of like how you can set up character studio so that characters interact with one another automaticly, walking about, avoiding one another, being afraid of something and trying to avoid it type of stuff. Not really necessary in a FPS type game, but it would be nice in SP RPG's if NPC's did more natural mundane stuff.

Ambient AI, eh? That's another good point actually. Active AI is where most of the focus of AI programmers inevitably ends up, because that's the core of the gameplay - the agents you fight with and against. But ambient AI is important too and it has a very different effect.

Like the kind of stuff we were told Oblivion was going to do before they became afraid it may break quests and pulled it all. It's a shame they lost their nerve in a way, because it could have been great. I agree that NPC's just wandering around doing their thing naturally would be convincing. It's like background music and sound effects. Even if you don't pay a great deal of attention to it, it helps to make a believable world around you. HalfLife 2 is pretty good with ambient AI, but it usually only does it with one or two characters at a time.

My biggest gripe with an FPS is when you can continue to shoot an enemy while he just stands there. It makes complete sense that you could sneak in and get a single shot, but once this happens, they need to react appropriately by taking cover or launching a counter-attack. (Or dropping to the ground if you are a good shot)

Some other things I like that I have seen in games.
-Enemies don't have to wait for you to see them before attacking you.

-One of my favorites,... When shooting a silenced weapon,... the enemy looks towards the point of bullet impact first, before turning around and trying to figure out where the shot came from.

-If there are 2 guys standing next to each other, and you take out one of them, the remaining one should realize something just happened to his buddy and take action.

Gabriel: In that case you really missed Dark Reign 1 and 2 if you were never ambushed :)

Great games for RTS AI and how they can make you fear them without just outnumber / out resource you like Blizzards and Westwoods AI

I hate games where you snipe someone from far away and suddenly the whole entire base knows exactly where you're at.....or vice versa...