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AI Detect You Without Even Looking
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You cannot sneak up to AI soldiers in this game. No matter how silent you are, even if his head isn't looking remotely in your direction, if you get to about 10-15 meters from the unit, he will suddenly start to rotate into your direction and then start firing.


Legacy ID
No Bug
AI Issues
Steps To Reproduce
  1. Open the ArmA 3 Editor
  1. Create a NATO unit "Man (Recon) > Scout" - Player
  1. Create a CSAT unit "Man > Soldier" - Non-playable; create him about 50 meters away and make him face away from the player unit.
  1. Preview mission
  1. Switch to your silenced pistol and then lower your weapon
  1. Go to walk speed and crouch stance, and begin approaching the CSAT soldier from behind (your footsteps are silent)
  1. Once you've come to about 10-15 meters the soldier will somehow be aware of your presence. This also occurs at night, even if the soldier does not have NVGoggles or acc_flashlight attachment.
Additional Information

I've tested this in daytime, pitch-black nighttime, blue-nighttime, etc. and this always occurs. I'm assuming that the silent movements with a lowered pistol while crouching may not be in, but the AI seems to hear your movements anyway. So it's probably an audible issue for AI or they just detect people in really close ranges.

Wonder if fixing this would also help with them seeing you through walls at close ranges too. :P

Event Timeline

Phronk edited Steps To Reproduce. (Show Details)Jul 31 2013, 2:35 PM
Phronk edited Additional Information. (Show Details)
Phronk set Category to AI Issues.
Phronk set Reproducibility to Always.
Phronk set Severity to None.
Phronk set Resolution to No Bug.
Phronk set Legacy ID to 2043027066.May 7 2016, 3:46 PM

try walking while crouching, i could sneak up to cm from the enemy, nothing to do tho, because there is no melee kill

tyl3r99 added a subscriber: tyl3r99.May 7 2016, 3:46 PM

i can get 5m away from him then starts turning.

IRL if someone is behind you crouching towards you... your gonna hear them arnt you. especially at night while on guard.

think about it.
however STEALTH CQB has improved ALOT!! try that

Phronk added a subscriber: Phronk.May 7 2016, 3:46 PM

Step 6 says to lower weapon AND crouch, then move towards the target. So yes, I know you make no noise whatsoever.

From what I can tell, I am making 0 sounds when moving with my pistol lowered and while crouched. Therefore, there should be no reason why he'd hear me. On guard or not, I'm not making noise. He's not seeing my shadow. He's not even glancing in my direction.

But as soon as I get to a certain distance, he always turns around at that distance.

confirmed I tested the AI behavior today for about 2 hours at least.
The AI has a high rate of detecting without hearing or seeing you, then shooting you

ceeeb added a comment.Aug 2 2013, 5:22 AM

This repro is reliant upon another currently assigned bug - #2208. Walking while crouched with pistol lowered should not be silent, Arma is just missing a sound effect for this movement mode. As AI use a config value rather than sound effects, the AI hearing is currently working as expected.

ceeeb, I believe crouched lowered pistol walking only makes no noise for the player, but to the AI it's probably equally loud, as doing the same move with a rifle.

So this might not be a bug, but it would simply mean that there is no reliable way to sneak up to an AI.

I am curious about time required to detect friend or foe, especially at night time.

During the day time, it takes soldiers a few seconds to identify friend or foe. At night time, it takes much longer before being able to distinguish friend or foe before shooting. In my experience, the enemy at night simply just shoot when they see you, as if they're on drugs and do not care whom they're shooting.

Svarr added a subscriber: Svarr.May 7 2016, 3:46 PM

Indeed, this needs to be fixed!

W4RH4WK added a subscriber: W4RH4WK.May 7 2016, 3:46 PM

i recorded an example and uploaded it.

Mission was Ghosthawk dawn available in the steam workshop.

I hope these issues get resolved before the game launches. It makes stealth missions a real pain in the ass.

ceeeb added a comment.Aug 16 2013, 4:17 AM

The repro video shows the player breathing heavily, which can now be heard by AI (see recent dev changelogs). The player is also walking over gravel/dirt, which is quite noisy. It is night and there are no other noises to cover sounds of the players footsteps. It seems reasonable to me that the AI can hear you in those circumstances, as it reflects reality.

What do you think the AI should do in that situation?

Shout, "Halt! Friend or foe?" Fire a warning shot or try to arrest if they're a reasonable military.

If on drugs and are terrorists, shoot wildly.

However, simply shooting with a head shot on the first shot seems quite unreasonable unless they're well trained terrorists with tons of equipment and have a ruthless dictator authorizing head shots for trespassers.

I think Novalogic's Delta Force had them running and shouting, and maybe with some sporadic lousy shooting. But once the trespasser shot once or twice without a suppressor, the enemy would open-up with all guns blazing.

Svarr added a comment.Aug 16 2013, 8:41 AM

Sorry, but what you have written sounds completely unreasonable. In this situation is shooting the only right thing to do. He knows that you are an enemy, because a friend wouldn't sneak up on his back and he had enough time to recognize you.
This is clearly a kill or be killed situation. If he had shouted or fired a warning shot, he would've been the one with the bullet in the head. I think we can expect that the AI is written accordingly. And most of the close contact situations in ArmA are in this manner. Missions without war are rare and the game is made for open war.

However, there are situations in which the AI knows things it shouldn't know. Especially your position. This is what should be fixed. And if it's really the floor, then there should be a sneaking pace.

I disagree. At night, it's extremely difficult to know if the person is enemy or a trespasser. Trespassers can look like they're snooping at night or look like they're walking straight toward you without knowing they're approaching an armed guard. Many variables to judge before simply shooting.

Tension may increase during different scenarios, such as war, but still need to verify before shooting unless they're drug addicts.

To say, the AI knows you're the enemy is a conclusion. The AI cannot know until they have verified by some means. Unless you're stating the AI knows because of programming structures. Then we can also now cite the AI are cheating. ;-)

The AI should assume a possible friendly is approaching based on noise from the trespasser. The AI then need to verify friend or foe, but again based on the AI's profile.

Im closing this as "no bug" since #2208 indicates most likely only a missing sound for the player.

To compare how it actually sounds to the AI, try sneaking up crouched with the rifle lowered.

I'm afraid currently there is simply no way to sneak up silently enough and would need a feature request.