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Learning the limits will help me greatly in making stealth missions.

How does knowsabout levels tie into detection? At what knowsabout does the enemy attack on sight ("HOLY F*CK IT'S HIM KILL HIM!")?

Does surprise attacking the enemy in darkness, with them having no NVG, then slinking back to the shadows and moving somewhere else work ("Huh? Where did he go?!")? Heck, how does evasion on breaking line of sight work (lol Metal Gear)?

Can anyone answer these questions? Thanks.

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I would advise not paying too much attention to knowsAbout. It is a rather esoteric variable that primarily measures how alarmed and suspicious a unit is. KnowsAbout can be a perfect 4, and the AI can be completely mistaken as to the enemy's position. IIRC, low levels of knowsAbout correspond to spotting of 'unknown' targets (no identification of friend or foe), and the AI starts shooting somewhere around 3. KnowsAbout is not always useful or reliable, but you can use it for triggers, because it means that a unit is alarmed.

Does surprise attacking the enemy in darkness, with them having no NVG, then slinking back to the shadows and moving somewhere else work

Yes, of course. But the hivemind-style information sharing of AI will make it very difficult to pull off against groups. When you break line of sight, the AI begins using your last known position, heading and movement speed to predict your location in real time. That is, they assume that once you go out of sight, you keep going straight on, without turns. Oftentimes, they will reacquire you the instant LoS is established, so long as you remain in their FoV. But this is mostly in daytime.

The key fact is that not all nighttime is the same. The AI will often reacquire hiding targets on brighter, moonlit nights. But at the darkest setting (experiment with dates), without NVGs, they are helpless and blind to all but gunfire and very nearby running.

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Okay, since knowsabout isn't the best judge, what is another alternative to gauging LOS, sound detection, among other things?

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That's all under the hood stuff. Why do you need to gauge that for a mission? Isn't it up to the player to look and see who has been alerted?

KnowsAbout is a good judge of results, since it shows that an AI has somehow received information about the player. Just remember that it gives no indication of the quality of that information. The AI you leave bumbling around in the dark as you vanish like batman will likely retain knowsAbout 4.0.

Edit: There are loads of good LoS scripts, as parts of mods and testing mission scripts. I don't know that you would want to use them, however, since LoS represents the possibility of detection. In a stealth mission, you're relying on darkness to mitigate the LoS of enemies.

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Learning the limits will help me greatly in making stealth missions.

How does knowsabout levels tie into detection? At what knowsabout does the enemy attack on sight ("HOLY F*CK IT'S HIM KILL HIM!")?

Does surprise attacking the enemy in darkness, with them having no NVG, then slinking back to the shadows and moving somewhere else work ("Huh? Where did he go?!")? Heck, how does evasion on breaking line of sight work (lol Metal Gear)?

Can anyone answer these questions? Thanks.

Some members of Comrades in Arms have researched these exact issues. You can see what they have came up with here:

http://ciahome.net/forum/index.php?topic=3032.msg22270#msg22270

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Excellent comments from maturin, but on this:

I would advise not paying too much attention to knowsAbout. It is a rather esoteric variable that primarily measures how alarmed and suspicious a unit is.

It's just an AI mechanism to simulate combat awareness, completely agree it means little to human players with much better logic skills, but i think watching the value in realtime will give OP a decent understanding of how the engine works, especially for stealth situations. Things can get quite random and complex sometimes, it's not all black and white.

My suggestion:

set up a player p1, a few opfor t1...t4

constantly hint knowsAbout for all of them and then go creep about/ shoot at different times of the day, on moonlit / no-moon nights, by yourself and with a team, and also with silenced weapons.

Watch the different values and how quickly it can go up and how slowly it goes down.

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This addon for Arma2 you may find interesting:

Infantry Stealth and Recognition Skills

http://www.armaholic.com/page.php?id=9604

quote from the release thread for the addon:

Fun testing results:

- With Audible at 0 enemy units cannot hear you at all, unless you fire a weapon, but can still see you (good for stealth adjustments).

- With Camouflage set to 0 enemy units cannot see you at all, unless you fire a weapon, but can hear you move (you can run around them in a circle, LOL)

- with both set at 0 enemy units cannot see nor hear you, once again unless you fire a weapon.

if we can "port" this to Arma3 stealth may then be useful.

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Probably premature. Have a Sniper Mod coming. The stealth part works amazing. IF you do the right things, there is a 90%+ chance per second the enemy could walk right over you. When you fire a weapon, though... the eventHandler to break stealth puts the frame-rates in the garbage; or even worse, locks the game up for several seconds. Never really played around with knowsAbout. :sneaky2:

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I actually have a stealth mission made but not release yet, but I was playing with knowsabout before I come down to this. I think I'll quote myself from the Comrade in Arms forums. The knowsabout will affect the detected by trigger so it is useful to know how it works there.

Seems like I fire a silence weapon near the guy but don't him them, knowsabout is now at 0.1 . The magic "detection" number for knowsabout is 0.7 . Whenever you shoot and your bullet hits the guy, knowsabout is automatically set to 1.5 (unless it is higher). Knowsabout can range from 0 to 4. At that point, the guy will need to die since alarm system is on 0.7 or else it'll trigger. Even at that point, its a gameble on whether the trigger goes or not since you're at 1.5 and if another AI besides that guy you killed is aware, alarm goes I guess. In that case, you're better off not even thinking about shooting any people. So if you have an alarm system using trigger detected by, probably best to not shoot unless Alarm goes off, so prefer way of beating this mission would be, don't get spotted, and only use silence bullets on light bulbs. After 2 min, knowsabout will reset back to 0

Loud/silence weapon also take an effect on your knowsabout level.

Loud vs silence weapons. My knowsabout went to automatically 1.35 after firing a loud weapon about 100 meters from the AI, I'm detected. Silence weapons, I'm not detected. I guess that makes silence weapons in Arma have a purpose to... shoot light bulbs but not people since you're automatically at 1.5 detection if you shoot people. This test is tested while firing a gun up in the air. Blowing up stuff with a satchel as well or placing a mine and having it explode will also affect knowsabout level. I did a little test shooting near people and such too and they're tested on unmodded AIs.

ARMA 3

MK18 silence to the side -> 1.35

P07 silence over the head -> 1.30465

MK18 over head loud -> 1.35

P07 over the head loud -> 1.35

MK18 silence shot up in the air for no reason -> 0

MK18 loud shot up in the air for no reason -> 0.8

P07 silent shot up in the air for no reason -> 0

P07 loud shot up in the air for no reason -> 0.45699

ARMA 2

All silence weapon -> 0.1

All loud weapon -> 1.35

Based on the above, seems like in Arma 3, whether you use a rifle or a pistol also have an effect. The effect above is based on shots near. Anyways, about shooting the AI itself, no matter what if you shot someone and you hit them, your knowsabout is automatically 1.5 . Like I said, magic alarm number is 0.7, you got to dispose of him fast or else the alarm trigger but at that point, other AIs might already get the message already so its a gamble and you're pretty much already detected. Don't even focus on stealth kills, not going to happen. So what are silence weapons good for? Shooting out lightbulbs, but the best design would be design around purely on evasion and no shooting.

Does surprise attacking the enemy in darkness, with them having no NVG, then slinking back to the shadows and moving somewhere else work ("Huh? Where did he go?!")? Heck, how does evasion on breaking line of sight work (lol Metal Gear)?

If you're going to do hit and runs, then knowsabout for you will be pretty high anyways, it won't go hand in hand with an alarm system. They'll be alerted of your presence of course. If you're doing pure sneaking with an alarm system, then basically avoid contact at all cost.

Edited by Phantom Six

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Also, I might add that the biggest obstacle for good stealth scenarios is probably the AI group hive mind phenomena. This bug makes an AI team immediately aware to the death of one of its members, even when no LOS or sound could have given that away. As long as the AI are in the same groups, even at two separate parts on the island, you'll get that problem.

Therefore, if you are to make a stealth mission, that encourage the player to perform any kind of silent take down, it's better to keep the AI ungrouped.

I'll add the bug on the feedback tracker soon.

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I've fired a suppressed shot at an enemy from over 15m away at night(pitch darkness + overcast), and they shot me with pinpoint accuracy. When they reloaded, i moved, they shot me still. They had no NVG's, no flashlight, and all the ambient lights were shut off.

this setSkill ["spotDistance", 0]; this setSkill ["spotTime", 0];

I've been using this on some of the sentries around a base, and it does seem to help a lot for a bit. If they see you though, they will shoot you even in complete darkness for a few seconds then it's like they lose your location and stop.

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Suppress weapons are not completely silent. You should still be able to here the small "pewpew" from that distance. Detected by also went up as you hit them (automatic start at 1.5 since your bullet touched them).

Therefore, if you are to make a stealth mission, that encourage the player to perform any kind of silent take down, it's better to keep the AI ungrouped.

If you do stealth takedown, don't use Detected by as a measurement for alarm. The moment you shoot and hit someone, the knowsabout is automatically 1.5 . Magic alarm detected number is 0.7 so you're screwed for that. An alternate alarm system I thought up but haven't made a proper mission off of it yet (so I'm not sure how that'll play out but sounds workable to me in theory) would be have all single AI no grouped scattered around in a big city (not a small base or else the guy next to him or around him will already know something's up), then you take them out 1 by 1 (like in Splinter Cell Convinction: Hunter gamemode, a bit more arcadey but that's how it'll work by).

Instead of detected by, I probably would try using detect DANGER mode for this kind of scenario and check if the AI is dead or alive. If AIs are close, more than 1 AI will go in DANGER mode so you have to dispose all of them. Danger mode too long and alarm off (alternate alarm, for a normal sneaking situation, don't use this... it'd be flawed).

Edited by Phantom Six

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Suppress weapons are not completely silent. You should still be able to here the small "pewpew" from that distance. Detected by also went up as you hit them (automatic start at 1.5 since your bullet touched them).

If you do stealth takedown, don't use Detected by as a measurement for alarm. The moment you shoot and hit someone, the knowsabout is automatically 1.5 . Magic alarm detected number is 0.7 so you're screwed for that. An alternate alarm system I thought up but haven't made a proper mission off of it yet (so I'm not sure how that'll play out but sounds workable to me in theory) would be have all single AI no grouped scattered around in a big city (not a small base or else the guy next to him or around him will already know something's up), then you take them out 1 by 1 (like in Splinter Cell Convinction: Hunter gamemode, a bit more arcadey but that's how it'll work by).

Instead of detected by, I probably would try using detect DANGER mode for this kind of scenario and check if the AI is dead or alive. If AIs are close, more than 1 AI will go in DANGER mode so you have to dispose all of them. Danger mode too long and alarm off (alternate alarm, for a normal sneaking situation, don't use this... it'd be flawed).

http://steamcommunity.com/sharedfiles/filedetails/?id=246184547

This is the most recent mission i've made as a tribute to the first 3 Splinter Cell games. SC, SC Pandora Tomorrow, and Chaos Theory.

As long as the lights are off, it's a lot of fun trying to make it through the whole mission undetected. Even the Mk20 is too loud suppressed, so I just use the .45. It's quiet enough to head shot most sentries without detection from others.

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Hehe, I got in the stealth groove again and made a mission after playing some Splinter Cell myself. I was playing the first one.

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what's the name of your mission? I want to try it out.

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I've fired a suppressed shot at an enemy from over 15m away at night(pitch darkness + overcast), and they shot me with pinpoint accuracy.

When they reloaded, i moved, they shot me still. They had no NVG's, no flashlight, and all the ambient lights were shut off.

WTF that sucks, why have suppressed weapons then, seems like AI is worse in Arma3 then in arma2, gees :j:

hope this can be fixed.

So thats you!

Cool, you built the omerta mission!

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They unfortunately still have super powers.

Example.

I placed two enemy ungrouped units on the map hidden from each other using a cargo container.

I then shot one unit dead, single shot using a suppressed weapon.

I then checked the remaining units knows about and it had risen a little which was ok.

After some time the unit rotated around to a point where he could see the other unit if the container wasn't there and magically his knowsabout value went to 4.

Also if they are grouped and one unit is killed and the others are on the other side of the map they still go instantly into aware mode.

If they have no radio that shouldn't happen and it should still take some time to simulate checking in.

Any chance of true stealthy missions in A3 is a no go they know too much all the time.

Edited by F2k Sel

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That to me is a real issue that has been in the series since the start, everyone, you, and AI automatically have a radio, they all also have night vision

even during the day which i find annoying, I can see now more in arma3 with its future setting, but among everything in the game that has been developed and worked on,

you would think that the AI would be given the most priority.

I've got to wonder and does anyone know this, can the AI see at all when you throw smoke, blocking your position?

If not then why do we automatically have smoke in our inventory if we are playing against AI, unless the intent was PVP all along, i dont get this, why put smoke canisters, why wear all the camouflaged, make the vehicles, planes, and weapons camouflaged if....the Ai can still see you when your in a forest with dark clothes, or in a plane, or chopper blending in in front of a hill, why go through all the trouble of this useless vanity "simulation" if these things dont actually do anything, its like older games when you play on the maps, you have a stage setup to create atmosphere,

the only thing real about it is your belief in the situation.

Seriously can we make this more simulated, more functional so that its believable, namely the AI's response, and function, what is

and is not working with the AI in terms of detection, should they not be responding based on their level of training?

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Yes Günter Severloh smoke works very well. Of course being Arma it still has issues AI see through smoke when looking at ammo supplies.

So if you deploy smoke and drop ammo and they need it they come through it.

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Just a suggestion / workaround.

addEventHandler Fired is a nice workaround for having some point on which the alarm of a detected enemy unit may sound for all the side / base. This has been used in lot's of stealth missions.

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Yes Günter Severloh smoke works very well. Of course being Arma it still has issues AI see through smoke when looking at ammo supplies.

So if you deploy smoke and drop ammo and they need it they come through it.

Excellent! I was throwing smoke in a mission in coop with some friends, and wasn't sure if it was actually working, or worked in Arma3 so thats good to know.

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Any way to extend the detection and engagement radius of ai vehicles beyond default using triggers or do I have to edit the vehicle configs?

If so, how do I go about doing it?

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