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AI make LoS detection check on sound source before target is inside FoV (Aka, eyes in back of head)
Assigned, WishlistPublic


Many players feel that the AI detects them with robotic radar senses. Although the AI rely on hearing gunfire or footsteps and then turning to acquire targets visually, this process has a problem.

The following is my longstanding observation on how the AI works. It is visualized in the repro mission with a script that denotes the perceived position of the AI's target with circles of red smoke. Confirmed targets are discreet balls of white and red smoke.

AI listen to gunshots and make a guess of where the source (target) is. This guess has a high degree of error. They then turn towards the target or scan the horizon.

Expected: When the source of the sound is within their field of vision, they perform a Line of Sight check. If it is positive and not diluted by range or fog, they acquire the target.

Observed: Alarmed AI turn towards the source of gunfire. Before the target actually enters the unit's field of view, a Line of Sight check is performed. The AI knows exactly where the target is before actually being able to lay eyes on it. This enables them to open fire on a target instantly, with maximum accuracy. They do not actually have to spend any time looking for the target.

Expected: The AI should not perform a target-acquiring LoS check until the target is actually within their normal FoV.

Further suggestions: If the target is at long range, wearing ghillie or prone in terrain with high camouflage value (talls grass, woodland areas of the map), the LoS check should be delayed. If the target is well concealed but LoS exists, the AI should fire on an area target of several meters, gradually zeroing in on the point target.


Legacy ID
AI Issues
Steps To Reproduce

I recommend setting timeacc to around 0.1 to observe this mission.


  1. Step out from behind the concrete barrier. Walk, so as not to give away your position audibly. (This close range best displays the FOV glitch)
  2. Fire a single round into the concrete barrier.
  3. Wait several seconds for the AI to become alarmed. KnowsAbout will increase, red circles of perceived position will appear on the runway around the player. Note the high degree of inaccuracy of the AI's position guess.
  4. When the AI has begun to swivel, KnowsAbout will suddenly increase to 4. Red and white smoke will burst from the player. This indicates that he has been spotted. At this point observe that the AI should only be able to see the player's position through peripheral vision, at best. He may even be looking through his own helmet.

Event Timeline

maturin edited Steps To Reproduce. (Show Details)Aug 27 2013, 8:01 PM
maturin edited Additional Information. (Show Details)
maturin set Category to AI Issues.
maturin set Reproducibility to Always.
maturin set Severity to None.
maturin set Resolution to Open.
maturin set Legacy ID to 3716921952.May 7 2016, 4:17 PM
Cypher added a subscriber: Cypher.May 7 2016, 4:17 PM

Yes, getting very tired of being magic-shot by AI. Not only are they far too accurate at all ranges, but to be able to instantly detect you from sometimes long range, or even when all you do is fire a supressed weapon one time, is completely ridiculous.

Upvoted so we can actually have a fair chance against AI, instead of seeming like its suicide mode.

maturin added a subscriber: maturin.May 7 2016, 4:17 PM

Please do not respond to this ticket unless you are going to be on topic. This is a place to discuss a single, highly specific, isolated bug, not to air general discontent.

Furthermore, if you switch the dev branch, I think you will find that the AI is now hilariously inaccurate. I'm talking getting 1 hit per full magazine at 200m...

The repro mission can be downloaded here:

This message brought to you by Devheaven's incalculable superiority.

If you move the player slightly close to the enemy in the repro, and don't walk anywhere (just move the concrete barrier aside), you can even get the enemy to spot you before he BEGINS to turn. That's truly eyes in the back of his head, far beyond any possible arc of peripheral vision.

Just adding the repro mission (is it possible to remove edit Additional Information and remove that?). Script is slightly updated to detect only the player

Here is an image of the issue. This occurs after a single gunshot that does not strike near the enemy AI. No other audio or visual cues are given to the player's position (I moved aside the concrete wall).

In this image the AI is now fully convinced of the player's true position. He is within what might be called peripheral vision, but I believe that at such distances it is highly inappropriate to allow the AI to acquire targets with peripheral vision. They should need to look directly at the target and search with their eyes.