zachary1975 on 1/2/2012 at 00:17

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Something that has annoyed me throughout the entire series is the way guards will respond to almost anything you do while the AI can do the exact same thing and the guards will think of it as normal.

the way i think AI should respond to certain things is:

Gaurd responses

When you leave the doors open (although this was only implemented into thief 3) the AI should one, if its the front door of a building he should investigate, two, if its a door in a prison they should close it, lock it and investigate and after a while give up and decide it was a gaurd or warden or someone else being careless however while searching he should alert gaurds near the exit(s) and then go back and search and afterward go back to his post or patrol but be more alert than before, three, if it's the back door two a business the gaurds should assume that their taking in a shipment, fourth and final, if a door inside a mansion is left open and is suppost to be closed the gaurd should, first, search the rooms joined by the door, second, ask anyone in the two rooms if they saw somebody use the doors and leave it open or if the left it open, and last of all, give up no more alert than before, close the door and return to their patrol or post.
If something is moved or missing as in not there but not necessarily stolen, one, if moved he should not pay any attention, two, if something not valuable is not there he should not be suspicous or pay any attention, three, if something valuable is not their, one, if it is something that is used, he should look around a little to see if it is being used and if it is not put back within 20 minutes he should ask the owner if he knows where it is and if not should alert the gaurds and search the building, third and final, if it is for display the guard should go straight to the owner ask if he moved it or told someone else to move it and if not should immediately inform all the gaurds and search the entire building and if not able to find anyone should to return to post or patrol but be on the lookout and be level 2 alert for the rest of the mission.
If a guard hears a noise which sounds like walking he should pay no attention, if the gaurd hears running he should immediately investigate, if he hears something that sounds like jumping or landing he should immediately investigate.

those are my ideas for the way i think gaurds should react to certain things. i'm still thinking of ways innocents should respond though.

wonderfield on 1/2/2012 at 05:53

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Seems like it might be too big a departure from the 'game-y' qualities present in the first two games (and, to a lesser extent, the third). They aren't overly-realistic, but predictable and relatively simplistic: just good game qualities. The AIs have a fairly basic and limited set of routines they employ when conditions arise (and there are few of them), and they return to their defined paths without ever spending too much time fussing about, generally speaking.

More behaviors make the game less predictable, and though it may seem like the right thing to do, that sometimes gets in the way of the fun factor. An ultra-deep AI behavior mode could be interesting, but it's probably not the best approach as the baseline.

R Soul on 10/2/2012 at 02:18

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How about:
If an object is marked as 'secure', it stores its initial position when the mission starts.

If the object is picked up by the player, an invisible 'missing object' marker, which is suspicious, is placed at its original location. The object also becomes suspicious. If it is dropped, it calculates how far it is from its origin. It deletes the 'missing object' and stops itself being suspicious only if the distance is below a certain value.

The other case would be if the object gets pushed around. If its velocity goes above 0, it periodically checks how far it's moved. If that distance exceeds a certain value, again you get a 'missing object' marker and the object becomes suspicious. If, during the distance check, the distance falls below the value, the process is undone.

demagogue on 10/2/2012 at 17:05

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Like jay said TDM has exactly this, except it's called an absence_marker. It's a bit fiddly since even though it's invisible it has to be well lit up & visibly placed so the AI "see" it, haha, but it still works. So yeah, this is definitely the best thing to do for it IMO.

But actually the tougher part I was talking about ... well I have to preface it. There was a guy that wanted to do more than absence_markers, like he wanted the AI to really recognize that it's his house, and he just left a room and is coming back, how could he not notice all this stuff strewn around? Can't there be a general mechanism so they always notice that, rather than me putting on absence_markers ad hoc?

And I was trying to communicate to him that it's not a trivial thing for AI to notice even "obvious" stuff that humans do, like unexpected objects or strange footsteps without the mapper directly marking it. You really have to simulate the lowest level things in the simplest ways, like he directly sees "marker" and goes "on alert". If you really wanted a general mechanism, you'd have to tag the "things", the "kind of room", whether the room is "familiar" & the "AI memory", whether the AI is "responsible for it" or not. I mean it's ridiculous the amount of stuff you'd have to track to do that, and even then some weird situation would still break it anyway. It's be much more work for the mapper (tagging all those things) than putting on a few markers for little to no extra payoff, and possibly being worse.

Or as Jay put it:

Absolutely.

For the record, though, that guy ended up using a hidden "put object here" objective covering the floor, so if objects fell on it, the objective worked behind the scenes to trigger the AI to alert when he was in the room. It was a clever compromise actually, a little better than the absence_markers for what he wanted but still achievable. Hopefully a few players notice it...