The AI's Biotic X-Ray Vision through certain objects: A bit of research on the matter

[maturin 12]

Yeah guys, I just tested a couple Utes bushes with a similar knowabout script. Including the one in PoorOldSpike's test.

Basically, the AI is quite willing to shoot through bushes, but it is a rare occurrence because he is lacking in common sense.

He is coded to expect units running out of line of sight to keep running and guess their position dynamically. But it doesn't seem to work with bushes. Even when you don't appear on the other side, he doesn't aim back at the bush.

*But* if you hide behind a bush that is only tall enough to conceal you when crouched, you can stand, reveal yourself, then lie down again and he will absolutely hammer you through the bush. I assume that this is because he knows you cannot dig down into the ground, even though he believes you can fly through the air.

[NeMeSiS 11]

*But* if you hide behind a bush that is only tall enough to conceal you when crouched, you can stand, reveal yourself, then lie down again and he will absolutely hammer you through the bush. I assume that this is because he knows you cannot dig down into the ground, even though he believes you can fly through the air.

If you tried my mission you would have noticed that changing stance makes a sound the AI hears, if you do it too much/too close to him he will 'lock' onto you and know where you are.

I could find absolutely no difference in behaviour between hiding behind a building, mountain or bush, except that bushes dont block bullets. In every case i was fully hiding behind the viewblock LOD my percieved position would just go on for about 50 meters.

Honestly i dont even understand what you are all talking about, a viewblock lod is a viewblock lod and it doesnt matter what the object its on looks like.

Edited April 11, 2011 by NeMeSiS

[pooroldspike 129]

You do realise that the AI is able to fire without a direct line of sight? :rolleyes:

Viewblock lods are guaranteed to block LOS, they just dont block bullets and the AI knows it.

Hmm this thread is getting more complicated the longer it goes on and I fear for the spiritual welfare of noobs who might be so confused as to seek counselling or take holy orders..

Are we agreed on this- If you're behind the centre of a bush the chance of the enemy spotting you is very small, but if you're slightly off centre the chances are greater, and if he spots you he'll fire through the bush?

[NeMeSiS 11]

Hmm this thread is getting more complicated the longer it goes on and I fear for the spiritual welfare of noobs who might be so confused as to seek counselling or take holy orders..

Are we agreed on this- If you're behind the centre of a bush the chance of the enemy spotting you is very small, but if you're slightly off centre the chances are greater, and if he spots you he'll fire through the bush?

There is no chance involved, you are either spotted or you arent.

EDIT: Except for grass i think, which is totally different.

Edited April 11, 2011 by NeMeSiS

[maturin 12]

If you tried my mission you would have noticed that changing stance makes a sound the AI hears, if you do it too much/too close to him he will 'lock' onto you and know where you are.

I could only alert him with moving (anything but a slow crawl), not stance changes, but I am running Zeus AI. It only improves some things, and can't alter the fundamental shortcomings.

I could find absolutely no difference in behaviour between hiding behind a building, mountain or bush, except that bushes dont block bullets. In every case i was fully hiding behind the viewblock LOD my percieved position would just go on for about 50 meters.

Yeah, that's unfortunate. I think BIS should place a high priority on fixing this, as it actually accounts for a lot of the AI's incompetence in CQB. Shooting AI who are looking in the wrong direction is how you get most of your kills up close.

Honestly i dont even understand what you are all talking about, a viewblock lod is a viewblock lod and it doesnt matter what the object its on looks like.

No, you don't understand. If you ran laterally behind an obstacle, your perceived position keeps moving perpendicular to the shooter. If you drop down behind one, your perceived position can't drop into the ground, hence the AI shoots at you directly.

Anyways, in more Utes tests I found that an AI 80m away is both less likely to be fooled and come up with strange perceived positions, and also more likely to shoot through the bush once he realizes that your are behind it. Also, automatic riflemen are happier to expend ammo on unseen targets. I would guess that unit skill will also affect fire discipline and hence whether they shoot through the bush.

There is no chance involved, you are either spotted or you arent.

There is no actual spotting involved, because the AI doesn't have eyes. The entire system is based on chance, and only occasionally does the engine draw lines of sight. Otherwise there would infinite numbers of rays projecting everywhere, slowing down a supercomputer. And there is partial spotting: the suspicion from hearing noises before visual contact is made.

In short: AI can't see through bushes. If they realize where you are based on noise or if they see you run behind it (and this is not exactly a common occurrence), they may, in some cases, open fire. It appears that weapon and distance may play a role.

Edited April 11, 2011 by maturin

[pooroldspike 129]

There is no chance involved, you are either spotted or you arent.

Wait a minute, you said this earlier- "The middle of a bush is almost always safe, just stop hiding behind the edges of bushes.."

What do you mean by 'almost safe', does the middle give 100% LOS block or doesn't it?

[maturin 12]

Wait a minute, you said this earlier- "The middle of a bush is almost always safe, just stop hiding behind the edges of bushes.."

What do you mean by 'almost safe', does the middle give 100% LOS block or doesn't it?

If it works like grass, then it functions as a factor making it less probable that the AI will spot you. Once he is aware of you, it might as well be transparent.

If you are 100% behind a viewblock object, you are 100% hidden. All else is probability.

Edit: And after testing with stone walls, I think I understand how to fool the AI, or not, when running behind obstacles. If you have momentum, they're going to abide by Newton's Laws and no matter which side of the obstacle you poke out of, they will be aiming about 50m to the side. They will correct quite quickly, however.

If you change your stance in order to disappear from sight, even if you dove into prone from a sprint, they will assume that you remain stationary while out of sight.

Edited April 11, 2011 by maturin

[NeMeSiS 11]

I could only alert him with moving (anything but a slow crawl), not stance changes, but I am running Zeus AI. It only improves some things, and can't alter the fundamental shortcomings.

I havent used ZEUS AI in ages, last time i used it it changed the sensitivity values i think, which wouldnt really matter at the ranges we test at. Anyway, i dont use AI addons as the messes up missions.

Yeah, that's unfortunate. I think BIS should place a high priority on fixing this, as it actually accounts for a lot of the AI's incompetence in CQB. Shooting AI who are looking in the wrong direction is how you get most of your kills up close.

No, you don't understand. If you ran laterally behind an obstacle, your perceived position keeps moving perpendicular to the shooter. If you drop down behind one, your perceived position can't drop into the ground, hence the AI shoots at you directly.

I am only going to talk about wether they can spot you through objects or not. If the estimation business is good or not is an entirely different topic and this topic is cluttered enough as it is.

There is no actual spotting involved, because the AI doesn't have eyes. The entire system is based on chance, and only occasionally does the engine draw lines of sight. Otherwise there would infinite numbers of rays projecting everywhere, slowing down a supercomputer. And there is partial spotting: the suspicion from hearing noises before visual contact is made.

Partial spotting is still spotting. And there is litterally no chance involved when it comes to hiding behind a viewblock lod, otherwise you could stand behind an object and still be occasionally spotted, which just doesnt happen.

(I find it hard reliably to test partial spotting, so i am just going to say that i cannot comment on it, in the end it still amounts to either being spotted or not)

And i am going to keep using words like 'hearing/spotting/seeing' since everything the game tries to do is pretty much summed up by those words.

What do you mean by 'almost safe', does the middle give 100% LOS block or doesn't it?

Yes it blocks the line of sight, however this does not mean you will not be shot.

[pooroldspike 129]

..If you are 100% behind a viewblock object, you are 100% hidden. All else is probability.

So if we get shot through a bush, it means we're not behind the centre of the bush?

We just have to guess where the centre is, and hope we've guessed right?

[maturin 12]

I am only going to talk about wether they can spot you through objects or not. If the estimation business is good or not is an entirely different topic and this topic is cluttered enough as it is.

Well I think their lack of X-ray vision has been conclusively proven.* But it's all academic except in terms of whether it improves gameplay.

So in this case, the perceived position estimator is preventing the AI from shooting through bushes and effectively suppressing targets.

*grass and aberrations exempted.

So if we get shot through a bush, it means we're not behind the centre of the bush?

We just have to guess where the centre is, and hope we've guessed right?

No. If you got shot behind a bush, it means you got shot behind a bush. The center of a bush is typically at the center of the bush.

[pooroldspike 129]

..Yes it blocks the line of sight, however this does not mean you will not be shot.

But if he can't see us, why will he shoot through the bush?

[NeMeSiS 11]

But if he can't see us, why will he shoot through the bush?

I already gave 2 possibilities when the AI shoots at you without a direct line of sight.

[maturin 12]

But if he can't see us, why will he shoot through the bush?

Because you would in real life, wouldn't you?

He isn't shooting at you, he's shooting at where he assumes you to be. He probably won't be very accurate, and neither would you. You would just hose the whole bush, he will shoot at a person-sized area of it.

Here's a link to my ticket regarding the estimation issue. Vote it up. http://dev-heaven.net/issues/18830

Edited April 11, 2011 by maturin

[NeMeSiS 11]

Voted.

[bravo409 13]

Im back you mother truckers...I've read what you guys have had trouble with and it sounds like some of you believe the AI is bit to all seeing....I have another reason to believe they see through walls I was playing a mission I made and this was a test to see how the AI reacted to my movement. I set my 3 guys on over watch at the top of a hill in tropica map to watch me inflitrate the little town on the water. Now its dark also so I run up to the town take guy out and move to a top of the building then tell my guys to open up after being on holdfire so they open up and kill some of the patrols but heres the weird thing I didn't shoot any shots after my first kill. Im on the roof and just watching the firefight take place then the enemy Ai start shooting at me and I was like how the hell did you see me when I didn't give my position away..Then I run down the steps and out the back the house to a new location and guess what? They where there shorty after at my position and I didn't fire one shot...I thinks that messed up I have played a game called farcry 2 and the Ai is none scripted and they handle much better than this AI....I know some of you are probably going to say go play that game then....LOL

Edited April 11, 2011 by bravo409

[maturin 12]

Uh, they heard shooting, looked around, and saw you?

That's what I could get from your post, and I don't see what you have to be complaining about. Maybe if you use proper grammar, punctuation and spacing, we would understand why you shouldn't have been spotting.

And you weren't on a BIS map, so maybe the objects don't block line of sight. You can't always trust modders.

This thread is for tests, not anecdotal evidence, so fire up Utes and try some things out for yourself.

[pooroldspike 129]

..Im on the roof and just watching the firefight take place then the enemy Ai start shooting at me and I was like how the hell did you see me when I didn't give my position away..

But if you could see them, they could see you..:)

PS- it's getting late here (3 a.m), I might run more tests tomorrow but for now I'd sum things up like this-

1-Putting something hard between you and the enemy (eg stone wall) is the only guaranteed surefire way not to get shot.

2- But a bush is much more risky because no way will it stop bullets if the enemy fires through it.

Edited April 11, 2011 by PoorOldSpike

[maturin 12]

Go test individual AI and they will prove to be very fair and limited. Stupid pushovers, even.

But once you have squads scanning for enemies from multiple angles, sharing instantaneous hive mind information about the entire battlefield, then it seems like you're fighting HAL.

[pooroldspike 129]

Go test individual AI and they will prove to be very fair and limited. Stupid pushovers, even.

But once you have squads scanning for enemies from multiple angles, sharing instantaneous hive mind information about the entire battlefield, then it seems like you're fighting HAL.

Absolutely, wargamers also call it 'Borg spotting'.

That's why my tests are usually one man against one man

[metalcraze 290]

Squads don't share info in vanilla. Otherwise your AI leader would be telling you to engage dudes other squad engages or sees.

I've played a lot of SP missions and sometimes the friendly squad just 100m away was totally getting wiped out by enemies, while my AI leader never even reacted, not even to a huge amount of gunfire going on, continuing to his waypoint.

Only GroupLink mod ever provided functionality like info sharing between squads

Im on the roof and just watching the firefight take place then the enemy Ai start shooting at me and I was like how the hell did you see me when I didn't give my position away..

Aren't you tired yet?

Roof is like the worst position for hiding ever with your head or even body being so clearly seen against the monotone sky. The AI also didn't notice you right away so what's your problem?

How do you spot enemies in the game btw? They didn't start shooting so they didn't give their position away right?

When I'm playing in coop we usually spot AI patrols 200-300m away moving behind dense lines of trees, something AI has a very hard time doing.

Edited April 11, 2011 by metalcraze

[maturin 12]

Squads don't share info in vanilla.

Yeah, I meant members of the same squad.

The other day I sniped the gunner of a humvee 10m in front of a seperate fireteam and they didn't care.

How do you spot enemies in the game btw? They didn't start shooting so they didn't give their position away right?

I'm guessing it was the usual mission. Making it dark, grabbing NGVs and going to fight insurgents expecting to be completely invisible.

[metalcraze 290]

Yeah, I meant members of the same squad.

Well they actually do pronounce a spotted enemy data to their squad members.

You can even hear bits of it when not in that squad.

Now the other AI guys being able to instantly understand where that enemy dude is from a non-descriptive info is another thing, whereas human players take their time to look for the enemy. This could've been balanced by a distance-dependable pause between the info pronounced and the moment AI guys know the enemy's position (e.g. the longer the distance the more time it takes for an AI to "know" that position).

But you know BIS, they ain't going to bother.

[LeadCommando65 10]

Because i was 100% behind the viewblock lod, hence he couldnt see me at all and the red arrow (where he estimated i was) was meters away from me.

I encountered what happens to you several times as well, if you move behind the bush while he is firing at you he may keep on firing for a while longer. Also, any suppresive fire would be directed at the arrow, not at me. Firing through bushes is rather rate, not usual behaviour.

I provided the demomission for a reason, try it yourself.

Can you please test other bushes as well? Because my own tests show signs that not all bushes have a correct viewblock LOD.

See here: bush view LOD tests

[Tonci87 163]

Well ok lets finish with the bushes. Let´s look at a house.

Example: There is an enemy Tank, there is me, a house is between us. I go to a corner of that house, the tank sees me and start firing his MGs at the corner. Even if I retreat quickly from that corner he still keeps firing at it. So basically he doesn´t take my Speed and movement direction into account, but thinks that I´m still behind that corner.

[maddogx 13]

There is an enemy Tank, there is me, a house is between us. I go to a corner of that house, the tank sees me and start firing his MGs at the corner. Even if I retreat quickly from that corner he still keeps firing at it. So basically he doesn´t take my Speed and movement direction into account, but thinks that I´m still behind that corner.

In my experience, this isn't always the case. It seems to depend on how far you were peeping out of the corner, how fast you were moving and perhaps some other factors. I've had tanks suppress my old position like you said, but I've also peeped around a corner a second time, only to see the turret scanning in the direction I retreated toward.

Anyway, in my own past research on this topic, using a similar script to the one Nemesis made, I came to the same conclusion as him: the AI in Arma2 does not have magical X-ray vision.

They try to estimate your position when you disappear behind objects, they sometimes suppress the place where they believe you to be (which may or may not be accurate), and they can use their hearing to improve their estimates.