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Enemy AI knows your exact position when you detonate explosives or satchel charges
Reviewed, WishlistPublic


If the player has been spotted by an AI unit,
and has subsequently broken contact and enough time has past for the AI to forgot about the player,
and the AI has line of sight with the player,
then the player's exact position is revealed to the enemy AI when the player sets of a remotely detonated explosive.

Repro with AI having seen then forgotten about the player:

Enemy AI should not know the players exact current location without a plausible detection mechanism (line of sight, sound, etc).
Detonating explosives should make the AI search/look around for the player (as occurs when AI who have never detected the player see explosives going off).

Repro with AI never having seen the player:

Repro with AI still remembering the player:


Legacy ID
Operating System
Windows 7
AI Spotting / Detection
Steps To Reproduce
  1. Load attached repro mission "24590_explosivesRevealPlayer.Stratis" in mission editor.
  2. Note the mission layout, including enemy tank location. The player is invincible for this mission. Hints show what the enemy knowsAbout you, and a red arrow indicates where the enemy thinks the player is (third person view recommended).
  3. Preview mission.
  4. Move toward the short Hesco barrier just inside the firing range (10m in front of your starting location).
  5. Place an explosive charge near the barrier.
  6. If the enemy tank has not spotted you yet, run around until it does. The hint will report knowsAbout value of 4 (although anything over around 0.2 will work).
  7. Retreat west behind the concrete walls of the firing range shelters. Turn on your GPS minimap (ctrl+M).
  8. Head north and follow the waypoints down the Hesco barrier corridor to get behind the tank without being spotted. If you are spotted after step 7 restart the mission. Feel free to use time acceleration.
  9. You will arrive at the end of the corridor (south of the tank). The tank should not detect you, as the gunner and commander are staring at your last known position. Continue east and find a location where you have line of sight with the tank, but would not reasonably be expect to be spotted. Concealment (hiding behind a tree or bush) reduces the chance of being fired upon, but certainly does not eliminate it.
  10. Wait until the knowsAbout value returns to 0.
  11. Detonate the explosive. Observe the tank commander and main turret instantly swing around to point directly at you, and fire (if player is at long range or concealed, they will sometimes not fire, but they are definitely made aware of you). If the player is behind cover (eg, behind a building this bug does not occur). Note that this occurs, even though the AIs thinks the player is at the detonation point.
  1. Repeat, this time setting of the explosives off before the AI forgets you. Observe the AI keep staring at your last known location.
  2. Repeat, this time placing the explosives without ever being spotted. Observe the expected plausible AI reaction (they scan the horizon, detecting player only if they are looking at you).
Additional Information

Related to same bug in Arma 2 OA:

It was resolved, to the extent AI would no longer instantly locate and fire on a concealed unit.

Event Timeline

ceeeb edited Steps To Reproduce. (Show Details)Jun 28 2015, 4:39 AM
ceeeb edited Additional Information. (Show Details)
ceeeb set Category to AI Spotting / Detection.
ceeeb set Reproducibility to Always.
ceeeb set Severity to None.
ceeeb set Resolution to Open.
ceeeb set Legacy ID to 2618749777.May 8 2016, 12:17 PM
Bohemia added a subscriber: ceeeb.Jun 28 2015, 4:39 AM
ceeeb added a comment.Jun 28 2015, 5:50 AM

Damn, didn't search hard enough first..

Duplicate of #12645

oukej added a comment.Jul 2 2015, 7:05 PM

Can you please confirm that if you detonate the satchel while the AI's knowsAbout is still 4.0, it behaves correctly and the AI doesn't pinpoint your current location?

ceeeb added a comment.Jul 3 2015, 12:21 AM

Yes, as per repro step 12 and third youtube video, with knowsAbout 4, the AI gunner and commander just stare at the player's last seen location when the explosives go off.

ceeeb added a comment.Jul 3 2015, 1:11 AM

I've done some further testing with AT land mines being used in place of explosives. Results are similar, but it takes a bit longer for the AI to look at and fire upon the player (I suspect distance from the explosion is also a factor, as the mine explosion occurs further away from the T-100 than the explosive charge used in the repro videos).

ceeeb added a comment.Aug 21 2016, 2:39 AM

Issue persists in dev build 1.65.138014

ceeeb updated the task description. (Show Details)Nov 21 2016, 9:16 PM
ceeeb edited Steps To Reproduce. (Show Details)
ceeeb edited Additional Information. (Show Details)
ceeeb set Operating System to Windows 7.
ceeeb added a comment.Nov 21 2016, 9:51 PM

Issue still occurs in current dev build 1.67.139357

I also suspect this issue also affects infantry, but the player must be within their field of view when detonating the explosives.