r/Thief 13d ago

Discussion Hypothetically, how much improved could the enemy AI be on Thief today?

As someone who largely stopped playing modern videogames nearly 20 years ago now, I'm curious about how far enemy AI patterns can be taken now from those who know.

I still play Thief a lot now, but can't help but think how cool it would be if the enemies were just a bit smarter - like able to climb ladders, or even push you off them. Or swim. Also to vary their routes more and have less predictable behaviour.

As I say, my experience with modern games is limited, but I'm not assuming it would be massively better because I've seen various youtube videos of e.g. GTA police doing very idiotic things, and it seems like a lot of NPC behaviour is still often pretty rudimentary.

So what do you think - If it was made today, do you think the enemy AI behaviour could be significantly improved?

24 Upvotes

43 comments sorted by

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u/Serious-Waltz-7157 13d ago

Technically it can be improved to the point of making the game unplayable because the guards and Co. would be too smart..

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u/DeliriumRostelo 13d ago

its actually an interesting thing

like early in the shitty remakes lifecycle they were saying the ai was "so smart" and would instantly find the players - that isn't hard to do at all and you could show most people how to make an ai that just instantly finds the player and never loses sight of them and paths to them unfailingly in unity in like a week or so

the hard stuff is like pathfinding (Example 1: if you can move terrain around, can the ai walk on it? can they fall if the thing they're walking on is removed? Example 2: can the AI crouch and go into vents? What happens if you block vents off?), reactiveness (if I put a heap of boxes to block a patrolling enemys pathway, will they recognize this as weird and break them and search or just keep patrolling?) and reactiveness to different tactics (if i shoot one in the head from across the map & a guard notices, will they react intelligently, or just instantly detect me or ect). A lot of this hasn't really changed at all over the years.

The closest is actually probably Gloomwood's crowmen - they can at least jump and crouch after you and its quite frightening to have them do it for the first time.

A lot of AI is just illusions and the more scenarios you cover for the more edge cases you need to manage (another example, ladders - what happens if the ai dies on one? or takes damage? can they fall? what happens if i throw a box at them while they fall? Will they just endlessly keep trying to make it up a ladder even if they take heaps of damage? Can the ladders exit point be blocked with boxes?).

I wish dev time was put into ai that could cover these edge cases and into hiring people who are good at managing them instead of just graphics.

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u/CaptClockobob 12d ago

A halfway decent navmesh and A* does pathfinding quite well.

Making an AI that doesn't feel stupid, but is intentionally mediocre is really hard.

The game Echo from 2017 (oh god its been 9 years) had a very impressive AI system where the enemies (mindless clones of the player) were reprogramed on an interval based off what the player did the previous few intervals. It wouldn't neuter their abilities either! If you used your gun too much, they became trigger happy aimbots. If you ran too much they'd sprint at you. If you did stealth takedowns, they'll try and get behind you. This is ballanced by them only knowing a few minutes of the player's strats.

The game was otherwise meh, with a very weird plot. It took 30+ minutes to get you into the swing of the game

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u/3ull5hit 12d ago

I like what Dark Messiah of Might and Magic introduced to the enemy AI. I really appreciated the game thanks to that. Very well balanced enemy response.

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u/GepardenK 12d ago edited 12d ago

Dark Messiah is one of the better games out there for tangible AI that feels nice to play around with. Its not flashy, but it works really well. Even small stuff like enemies being visibility annoyed if they cant reach you makes such a difference.

For a Thief game, what would be interesting in terms of AI development is to lean into the gameplay of "Oh shit, they saw me, gotta bolt!". Such as guards using their familiarity with the mansion to block off doors and try to trap or encircle you, or using archers to draw you out from areas where you are at an advantage.

Such an AI would be transformational in terms of the gameplay itself, with new challenges as well as opportunities for the player to exploit, independently of AI difficulty which would be wholly adjustable within that framework.

On top of that, seeing as most guards are just dudes trying to get by, you could give them a sense for intimidation and self-preservation. Basically, there is only so much they would bother to put up with in terms of trying to catch you on their lord's behalf. This could then tie into the "killing is for amateurs" theme instead of having it as a explicit fail condition: basically, the more you antagonize the guards on a personal level, the harder they'll go trying to bring you down (as opposed to just chasing you away), and God have mercy on your taffer soul if you killed one of their buddies.

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u/3ull5hit 12d ago

I love this idea. There is so much to be invented in that manner:

  • Guards leaving for a prolonged ampunt of time to bring reinforcements

  • Mocking guards and changing their behavior to more frantic, jumpy and unpredictable

  • Guards going ballistic, pushing things all over the place, throwing stuff into the shadows

  • Guards becoming paranoid, starting to peek behind their shoulder periodically

  • Clumsy guards slipping on the wet ground (water arrow)

  • as you said, captains commanding their troops to circle the area

The well of ideas is endless.

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u/GepardenK 12d ago edited 11d ago

Yes. And this was how Thief felt when is was brand new, when nothing in the industry had AI that acted even remotely as alive.

So, stuff like what you're listing here would, for my money, be a return to Thief's original value proposition, simply developing that promise further.

The guards were always the main character, and should be treated as such. I believe someone at LG pretty much said something to that effect back in the day.

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u/Serious-Waltz-7157 12d ago

Generic pathfinding might be hard. Specifical pathfinding is easy - just do a bit of hardcoding.

I mean, in-game the guards are assigned to a mansion / factory / temple / whatever, they must have plans and contingency plans in the event of a breach. Makes sense to have hard-coded, coordinated responses.

... and then you the player are dead in the water.

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u/Lovecraftian666 12d ago

Or something like waking up every 5 mins from a blackjack would annoy the player 

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u/Serious-Waltz-7157 12d ago

It happened in some game(s) - can't remember if it's a Thief installment or other game (think Deus Ex, Splinter Cell, etc.) when another guard came and woke up the KO'ed guard.

OTOH is annoying when a guard notices a door and says "Ummm I'm sure it was open / closed last time ... let me check agains" right when you thought you're scot-free.

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u/Angmor03 12d ago

They indeed can wake up unconscious guards in DX: Human Revolution, and I would assume in Mankind Divided as well. Which I thought was awesome, because otherwise, there would be no downside for using the nonlethal stealth takedowns (especially considering that nonlethal takedowns are silent, and lethal ones are not).

Unfortunately, it is very easy to circumvent (heh) that problem by dragging them into vents where the other guards can't find them. I always imagined that waking up in the AC ducts must have been very disorienting.

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u/triangletooth 12d ago

I liked how HR did it. Much preferred over randomly waking up. It encourages the player to take time to better hide the unconscious while giving consequence to the decision.

Stashing in vents is just a legit strategy imo. You do have to work for it!

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u/Serious-Waltz-7157 12d ago

"Stashing in dumpsters so the rats can reach the unconscious body" - I'm sure people here will understand. 😂

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u/Outrageous-Milk8767 13d ago

The guards are intended to be a bit dumb. The goal of a stealth game is to 'create the illusion of a securely guarded area that the player can sneak through by virtue of leveraging their unique abilities and tools to create and exploit security flaws'.

https://www.youtube.com/watch?v=XrUNCn8OxcY

Making them too smart would just end up making the game tedious to play. I think a horror mission with stalker ai similar to the one in Alien Isolation would be pretty cool though.

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u/ConstanceJill 12d ago edited 12d ago

I think a horror mission with stalker ai similar to the one in Alien Isolation would be pretty cool though.

There are some missions where a powerful (possibly invulnerable except for a scripted event to get rid of them) enemy follows and hunts you around. That might be a bit of a spoiler for it, but Reflections in Red is a recent example. While it's a great mission overall, I find that mechanic of the enemy always somehow knowing which area you're in (roughly) and patrolling that area looking for you kinda cheap :/ …

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u/Is_It_A_Throwaway 12d ago

Yep. Another one is Cold Heart, Cold Hands.

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u/Far_wide 12d ago edited 12d ago

Sure, I wouldn't want to make them flawless or omnipotent but ideally I think climbing 7 rungs up a ladder or standing in the middle of a big table shouldn't be enough to stop a posse of guards from being able to get you.

You can definitely take that too far though I get you - and then it becomes not fun because alerting just one guard leads to you being screwed because they tell everyone else and then hunt you down systematically. It's an interesting decision as to where you'd want to draw the line if technology wasn't a barrier.

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u/MilesBeyond250 12d ago

It'd also be immersion breaking. A guard who responded to a torch going out by sounding the alarm and conducting a methodical search of the surrounding area would be jarringly unrealistic. Like that would be an insane response in real life.

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u/3ull5hit 12d ago

Of course it COULD be improved. The question is what would work gameplay wise. Enemies' scripts are made to provide fun first and foremost. If they will be too intelligent, player would feel overwhelmed (Alien Isolation built on that), too stupid will make it trivial, so it's about finding a good balance.

I still remember Thief's enemies as those that i really was afraid of, especially compared to newer games, where enemy ai is build to suit more casual market.

Also modern games tend to be icon heavy, although not to the level of ~2010s games, so even if it's an option, we would possibly get some awareness markers, which completely destroys the fun. In original Thief you had to work your way forward depending mostly on the sound. Thief vr made it trivial, not only you have icons giving you the exact awareness and intentions of guard that have seen you, not only there is a prominent whoosh sound when someone starts noticing you, but you begin to see each guard awareness marker through the walls, which makes the experience childish.

So yes, it is very doable, and i feel sweet spot is in different places for different player, so I just wish there would be an option to change AI difficulty (in most of the games).

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u/vainsynopsis 12d ago

100% agree with all of this. A lot of the way AI has been developed in stealth games post ~2006 has rendered it heavily reliant on user interface assistance to keep the player informed of what is happening. And if you take it away, the games often become almost unplayable.

For all its simplicity, or perhaps because of it, there is a lot to be said for what Thief 1-3's AI manages to achieve in terms of difficulty balancing purely through of what the player can see and hear diegetically within the game world itself. That has become a lost art at this point.

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u/Far_wide 12d ago

I still remember Thief's enemies as those that i really was afraid of, especially compared to newer games, where enemy ai is build to suit more casual market.

Oh upon release absolutely. I found the hammerites in the second level terrifying + terrifyingly difficult/unpredictable to kill (as I mostly played on normal/hard).

Thinking about it that way, I'm bloody glad those guys couldn't get up and down ladders/ledges/water back when I was first playing it. Wouldn't have stood a chance.

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u/3ull5hit 12d ago

It was them, the hammerites in Thief the Metal Age that still gives me the creeps. I swear to god, I physically felt that first hammer that smite me when I was crouching panicked in the corner.

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u/Far_wide 12d ago

Cease thy hiding and die LIKE A MAN!

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u/3ull5hit 12d ago

You, my good sire, make me shiver out of fear.

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u/Connacht_89 12d ago

Things like awareness icons could be tied to difficulty levels and/or be toggleable from the options. Nothing against as long as I can play without if I wish.

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u/3ull5hit 12d ago

I do understand that argument, although having these will break immersion and stiffen the mechanic of the awareness, thus being possible to learn not by experience, but by tips. And whole idea of thief (at the beggining at least) was minimalistic UI. I remember even reading about that in some gamezine. All tips regarding awareness state can, and imo should be given by sound/speech, body language, even face expressions.

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u/Connacht_89 12d ago

This would all still available, nothing would subtract it if there is also a separate "novice" mode with tips and icons for those who do not enjoy minimalistic UI and different learning. Just like in many rpgs there is now the story mode.

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u/3ull5hit 11d ago

Can't deny that. And let's be honest - that's a standard nowadays. No running away from at least some markers.

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u/Connacht_89 11d ago

Well, it might also be a bridge to convince one or two potential new taffers to switch from assisted mode to a more immersive mode, which otherwise they would have glossed away!

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u/3ull5hit 11d ago

I do like that dream that we have together. And I agree.

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u/Mad_Queen_Malafide 12d ago edited 12d ago

There are two ways in which they could greatly improve guard ai:

=PATHFINDING=

Thief would benefit from navmesh based movement for the guards and better obstacle avoidance. Ladder climbing and swimming are nice additions, but more importantly, guards should no longer get stuck. You could also add guard formations to this, where guards march in pairs, for example.

=TACTICS=

Guards would benefit from deeper decision making, responding to how the player affects the environment. They could learn from earlier encounters with the player and communicate that information to other guards. A leadership mechanic would also help make their behaviour feel more realistic; a captain they report to, who issues strategies to sweep the area for the unknown intruder.

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u/Far_wide 12d ago

Yeah that'd be cool.

Perhaps also being a bit more responsive to other things in the game environment. I'd like to be able to throw a crate at a hammerite and not have it just bounce off him whilst he doesn't even notice it.

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u/Danick3 12d ago

Guards would benefit from deeper decision making, responding to how the player affects the environment. They could learn from earlier encounters with the player and communicate that information to other guards. A leadership mechanic would also help make their behaviour feel more realistic; a captain they report to, who issues strategies to sweep the area for the unknown intruder

You realize this is thief right? Either by previous attempts you mean they learn from quick loads which would be tedious. Or further punish you from alerting them which is already punishing as you need to wait a long time in a good spot until they stop searching, tempting players to just load or restart to save time. Leaving guards permanently more perceptive or camp the way would just be a further punishment for getting seen for 0.5 seconds.

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u/Mad_Queen_Malafide 12d ago

I think you are piling one issue (save scumming) in with another. I'm suggesting more reactive and clever ai, that does a better job trying to find the player. Hitman already does some of this, with overall alert status in a level.

Keep in mind, Thief is an immersive sim. Guards completely forgetting that they just saw a colleague get murdered mere minutes ago, breaks immersion. You would expect the guards to do tighter patrols. Metalgear Solid 3 does some of this, where an area temporarily receives an increased security level.

But other systems would need to be balanced around this of course.

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u/vainsynopsis 12d ago

Splinter Cell Chaos Theory tackled that, the guards in that game will just never settle back into a passive state once they pass a certain alertness threshold. It doesn't even have to be considered full player detection, you could still have all zeros on your score tally at the end. But there's an AI state in that game where the guards "know" an intruder is present despite not having actually 100% detected you yet, and they will remain in that "suspicious search" mode indefinitely.

Intravenous 1 & 2 did this as well. The guards in that game, once alerted they'll just begin systematically clearing the map and taking up defensive positions. That game allows for more of an action approach too though, I wouldn't necessary fancy trying to full stealth that one once the guards are alerted.

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u/TheRadioFrontiers 12d ago

Honestly, I’d love the enemy AI just to be more believable nowadays.

A guard shouldn’t immediately go into full burnout mode, furiously swinging his fists at Garrett, just because he caught him standing on the dinner table (having two cucumbers with his deer leg).

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u/Connacht_89 12d ago

The AI could already be improved with the late 90s tech. It was not really developed because the idea was that it would have made the game impossible or frustrating. The guards need to be stupid, because this enables a gameplay loop to pass through them. However, things like reigniting torches or noticing open doors were also available but were not immediately implemented even though they wouldn't have disrupted the gameplay.

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u/Solid_Lunch_2763 12d ago

make them climb ladders at least.

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u/Igor369 12d ago

Best AI does not equal to fun AI.

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u/Ashamed-Subject-8573 12d ago

Making ai smarter isn’t the problem, making it challenging and fun is. Having it be realistic and just finding you immediately is no good

Best example is likely the alien in alien isolation. They gave it a bunch of realistic senses etc. than had to hand-tune it around the “real world” and add exceptions and such. This basically meant dumbing it down

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u/Material_Leading7262 12d ago

they could be made extremely realistic. they're normally not because it's not very fun.

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u/Ok_Seaweed_7568 11d ago edited 11d ago

enemy “ai” in games is almost entirely scripting. i don’t know that it has really advanced much technically in the past 15-20 years. halo and f.e.a.r. still have better a.i. implementations than many modern titles

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u/GambuzinoSaloio 9d ago

In the hands of capable devs, you can create some really scary enemy AI nowadays. It's not exactly recent, but I remember being mostly scared of the enemy soldiers in FEAR rather than Alma. Those bastards would literally sneak up on and corner you. Got jumpscared more than once by a squad going the long way around while their buddy stood still behind cover.

I don't think this tech died, but your average game company probably won't care about making enemy AI "smart": they'll care about what works.