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

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

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

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.

Indeed, this needs to be fixed!

i recorded an example and uploaded it.

Mission was Ghosthawk dawn available in the steam workshop.

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

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

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.

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.