Threat Detection

Documentation Unreal Engine AI Threat Detection

Turn the player's camera attention into a 0 to 1 reading, and make an enemy swap sides or give ground under a stare.

An enemy that feels your camera on it. Hold a stare and it flips the side it circles on, or backs off to buy itself room.
Viewport
LVL_SEC_Showcase>Threat
Enemy strafes around the player. Aim toward the AI to raise threat (even outside the 15° cone); hold inside the cone for 3s to fire On Threat Duration Exceeded and swap strafe side when the profile allows it.

Set it up

30 seconds
  1. 1

    Check the controller carries the component

    An AI controller made from EnemyControllerBase ships a Threat Detection component and needs nothing added. On your own controller, add Threat Detection to the AI controller, not the pawn.
  2. 2

    Turn on a response

    Open the enemy's Movement Behavior Profile and under Threat Response tick Swap Strafe On High Threat and Adjust Distance By Threat. Both ship off, so this is the step that makes a stare visible.
    DA_MovementBehavior_Attacker
    ▾Threat Response
    Swap Strafe On High Threat
    Adjust Distance By Threat
    Both switches ship off. Tick them and a stare reaches movement. Threat Distance Scale under them stays greyed until Adjust Distance By Threat is on.
  3. 3

    Play, and stare at it

    Press Play, point the camera at the enemy and hold it there. Three seconds of looking flips the side it circles on. With Adjust Distance By Threat ticked as well, it widens the range it holds for as long as the camera stays on it.
  4. 4

    See the numbers behind it

    Run SEC.Debug.Threat.Draw 1. A cone draws forward from the player, and a ring above the enemy closes white through orange to red as the stare completes.
Threat reads the controller's focus actor, and nothing sets that until a combat target is registered. An enemy with no target sits at 0 however hard you stare at it. See Getting Started and Targeting.

Two readings, two questions

Threat level is how directly the focus target aims at this enemy, from 0 to 1. Any pawn contributes its control rotation, which for a player means the camera direction rather than the character's facing, so a player who swings the camera off an enemy reads 0 even while running straight at it. A focus actor that is not a pawn contributes its forward vector instead. The value tracks the aim frame by frame and carries no history.
The stare timer runs only while that aim sits inside Player Look Angle Threshold of the enemy. Hold it for Player Look Time Threshold and the duration event fires. Look away and the timer clears.
The two disagree on purpose. Threat level can read 0.7 while the timer has not started, because the camera points broadly toward the enemy without landing inside the cone.

Tune the stare

Details
Threat Detection Component
Threat Detection
Player Look Angle Threshold
15
Player Look Time Threshold
3
Debug
Debug Log Threat
Debug Draw Threat
Sits on the AI controller. Evaluation starts off on a controller made from Enemy Controller Base, and the SEC Combat Controller turns it on at BeginPlay when Enable Threat Detection is ticked.
FieldDefaultWhat to do with it
Player Look Angle Threshold15 degreesHalf-angle of the cone that counts as looking. Widen it toward 30 for an enemy that answers a glance, tighten it toward 5 for one that answers a dead-centre stare only. Accepts 5 to 90.
Player Look Time Threshold3 secondsHow long the stare holds before the duration event fires. Accepts 0.1 to 10.
Each time the duration fires, the timer resets and the next threshold rolls a random value between the base and double it, so a pack caught by one stare does not swap sides in lockstep. Looking away puts the next threshold back at the base value.

Make movement answer it

Both responses live on the movement profile, so each combat role can answer a stare its own way.
Details
Movement Behavior Profile
Threat Response
Swap Strafe On High Threat
Adjust Distance By Threat
Threat Distance Scale
1
Role-swapped fields on the active movement profile. Both switches ship off on a new profile.
FieldDefaultDoes
Swap Strafe On High ThreatoffEach completed stare flips the side the enemy circles on.
Adjust Distance By ThreatoffThreat widens the range the enemy holds, continuously rather than in steps.
Threat Distance Scale1.0How far that widening goes. The held range is multiplied by 1 + threat x scale, so scale 1 under a dead-centre stare doubles it. Accepts 0 to 5.
The SEC Combat Controller component is what carries a stare into movement. It binds the two threat events at BeginPlay and drives the Movement Evaluator on the same controller, so both components have to sit on that controller for either switch to do anything.
The profile that answers is the one the enemy's current role resolved to. Editing Default Movement Profile changes nothing for a role that has its own entry in Role Movement Profiles.

Read it yourself

Movement is the one response SEC wires on its own. Everything else, a bark, an animation flag, a boss phase, binds to these.
NodeGives you
Get Current Threat LevelThe 0 to 1 reading, this frame.
Get Player Look DurationSeconds the current stare has held. Clears when the player looks away.
Is Player Looking At MeWhether the aim sits inside the angle cone.
Is Threat Detection EnabledWhether evaluation is running on this component.
On Threat Level ChangedFires when the reading moves by more than 0.01.
On Threat Duration ExceededFires when a stare completes, carrying the seconds it took.

Debug it

SEC.Debug.Threat.Draw 1   // Look cone from the player, filling ring above each enemy
SEC.Debug.Decision 1      // Threat, distance, angle, sight and speed above each enemy
The cone turns red the moment the aim crosses inside the angle threshold, and the ring drawn about a metre above the enemy closes white through orange to red as the timer runs toward its current threshold.
The decision line is an overlay section, so SEC.Debug.All 1 brings it up with the rest and SEC.Debug.WatchPawn <name> narrows the overlays to one enemy. The threat drawing has its own switch and answers to neither.
The Threat Detection component carries the same two switches per enemy. Debug Draw Threat draws the cone and ring for that one enemy with the console variable off. Debug Log Threat writes a record instead: the look angle, the running timer against the threshold it is chasing, and the length rolled for the next one.
AdvancedNothing answers the stare
In the order worth checking:
  • No combat target. No focus actor means no threat, and this logs nothing at all. It is the common one.
  • Both profile switches are off. A new Movement Behavior Profile ships with Swap Strafe On High Threat and Adjust Distance By Threat unticked.
  • The role uses a different profile. Check Role Movement Profiles on the AI Config before assuming Default Movement Profile is the one in play.
  • No Movement Evaluator, or no SEC Combat Controller, on the controller. The switches have nothing to drive, or nothing to carry the events to them.
  • The component sits on the pawn. It belongs on the AI controller. Anywhere else it warns once at BeginPlay and stops.
  • Enable Threat Detection is unticked on the SEC Combat Controller component, so a controller made from EnemyControllerBase never starts evaluating.
  • The enemy died. Shutdown turns threat evaluation off, and a revive turns it back on.
AdvancedSwitching evaluation off, and throttling it
Enable Threat Detection on the SEC Combat Controller component turns evaluation on at BeginPlay. It ships ticked, and a controller made from EnemyControllerBase starts with evaluation off, so this box is what starts it.
Details
SEC Combat Controller Component
Threat Response
Enable Threat Detection
Binds the threat events at BeginPlay whenever a Threat Detection component sits on the same controller. Enable Threat Detection turns evaluation on there and never turns it off.
Unticking it leaves that switch-on undone and never turns a running component off. A hand-built controller carrying the component without the base class starts evaluating on its own, so call Set Threat Detection Enabled with false to stop it.
Set Threat Detection Enabled flips it at runtime. Switching it off clears the reading, the timer and the looking flag, and the component keeps ticking so the debug drawing still works.
Set Tick Interval throttles evaluation, in seconds between updates, where 0 evaluates every frame. Raising it toward 0.1 on a crowded arena costs a three second stare nothing.
The delegates bind whether or not evaluation is enabled, so a handler stays connected across an off and on cycle.
AdvancedLetting a stare bias which move an enemy picks
No shipped scorer reads this component, so an action favours nothing on its own while the player stares. Write one of your own:
  1. Make a Blueprint child of SEC Scorer.
  2. Override Score Multiplier. Take Controller off the context, get the Threat Detection component from it, and read Get Current Threat Level.
  3. Turn that 0 to 1 reading into the multiplier you want. 1 leaves the action where it was, above 1 favours it, below 1 pushes it down.
  4. Add the scorer to the action's Scoring > Scorers list, the same as a shipped one. See Action System.
The figure the overlay prints alongside distance and angle is a different one: it lives on the decision context that feeds the brain and never reaches a scorer. Read the component for camera attention.
The same scorer in C++ is in the API Reference.
AlternativeWiring it without the SEC Combat Controller
The component senses and broadcasts; it drives nothing and holds no reference to movement. On a controller without the SEC pieces:
  1. Add Threat Detection to the AI controller.
  2. Call Set Threat Detection Enabled with true.
  3. Bind On Threat Duration Exceeded, or On Threat Level Changed, to whatever the stare should cause.
Focus still has to come from somewhere, either Set Focus on the controller or SEC targeting.
AdvancedThreat next to awareness
Awareness answers what this enemy has sensed: whether it has spotted a target, how sure it is, where it last saw it. Threat answers the opposite direction, whether the target is paying attention to this enemy.
They share no state and neither gates the other. An enemy can sit at full threat while its awareness has lost the player behind a pillar.