Targeting

Documentation Unreal Engine Player Combat Targeting

Targeting picks the enemy the character fights, locks onto one on a button, switches the lock with a flick, and knows when enemies are near. UPC Targetable makes any actor a candidate.

Set it up

5 minutes

1
Make a dummy targetable
In a Character Blueprint that stands in as a training dummy, click Add and pick UPC Targetable. Set its Aim at Socket to the skeleton's chest bone, such as spine_03 on the engine's mannequin. Place the dummy in the level.
Components
+ Add
BP_TrainingDummy (Self)
CapsuleComponent
Mesh
UPCTargetable
Add
A dummy on no team can be picked and locked. A character built on UPC Character Base is targetable already.
2
Check the player's targeting and lock button
The player's TargetingComponent, which UPC Character Base creates, takes its Targeting Config from the combat style's Targeting fragment, such as the Over Shoulder config CombatStyle_MyStyle names (Combat Styles).
The lock button is the UPC Lock On Ability, which the demo's AbilitySet_UPC_Default grants. On your own character:
1. Create an ability set (right-click in the Content Browser, UPC > Actions > Ability Set) named AbilitySet_MyCharacter.
2. On a character built on UPC Character Base, pick it as Starting Ability Set in the Class Defaults. A character that keeps its own parent has no such slot: add the set to Ability Sets to Grant on its Default Item's Equippable fragment (Character Setup).
3. Add this row (Input), leaving Forward Input While Active off so the second press lets go:
AbilitySet_MyCharacter
▾Granted Gameplay Abilities > Index [ 0 ]
AbilityNone
Input TagNone
Input Action
None▾
A mapping context on the player maps IA_UPC_LockOn to a key: the demo controller's IMC_UPC_Default maps it to the middle mouse button and the gamepad's top face button. On a controller of your own, add a context that maps it.
3
Press Play and lock on
Put the dummy near the middle of the screen and press the middle mouse button: the camera follows it and the character carries UPC.State.LockedOn. Press again to let go.

How a character picks its target

The Targeting component finds actors with a switched-on UPC Targetable within Scan Radius, drops those Target Teams leaves out, and ranks the rest with the config's score policies. Each policy rates a candidate from 0 to 1 or vetoes it; a veto or a total of 0 drops the candidate. The best becomes the current target (the soft target while nothing is locked), which Attack Steering reads. A lock press makes its own pick (Lock on).

Candidate	Distance	Distance score	Angle off view	View Angle score	Blend
A	7.2 m	0.64	8°	0.91	0.73
B	4.9 m	0.76	35°	0.61	0.71
C	15.0 m	0.25	2°	0.98	0.49
D	5.7 m	0.72	26°	0.71	vetoed

A selection pass under the demo's Soulslike soft-target policies: Distance (Weight 2), View Angle (Weight 1) and Line Of Sight (Weight 0, a veto only). Each score is the weighted average of the two scoring policies; D sits behind a wall, so Line Of Sight drops it whatever it would score. The highest score is the target.

Make an actor targetable

A lock aims at Aim at Socket, a socket or bone, on the first component that has that socket, or on the component tagged Aim at Component Tag when that is set. Aim Offset moves the point, in centimeters. With neither set it aims at the actor's location.

Untick Targetable, or call Set Targetable, while the actor is down or out of the fight, and every lock on it lets go. Release All Locks lets go of every lock and leaves it targetable, for a phase change or teleport.

The Targeting Config

Duplicate the demo config nearest your fight and tune it. Hand it over through the combat style's Targeting fragment, or the Targeting component's Targeting Config on a character with no style.

Config	Picks
`TargetingConfig_UPC_Freeflow`	The enemy the stick points at, within a dash (8.5 m). No lock-on; engages at 10 m and lets go at 13 m.
`TargetingConfig_UPC_OverShoulder`	An enemy within 4 m, ahead of the character and within 45 degrees of where the camera looks (Measure from Character: measured from the character along the camera's direction).
`TargetingConfig_UPC_Soulslike`	The nearest enemy, favoring the center of the view.

The two lock configs lock within 20 degrees of the screen's center, let go past 25 m, and switch on IA_UPC_Flick. To build one from nothing, right-click in the Content Browser, UPC > Targeting > Targeting Config.

Details

TargetingConfig_UPC_OverShoulder

Scoring

Score Policies

3 Array elements

Index [ 0 ]

Distance

Max Distance

400

Veto Beyond Max Distance

Weight

Index [ 1 ]

Line Of Sight

Trace Channel

Visibility

Trace from View

Weight

Index [ 2 ]

View Angle

Max Angle Degrees

Veto Outside Max Angle

Measure from Character

Weight

Lock Score Policies

2 Array elements

Index [ 0 ]

View Angle

Max Angle Degrees

Veto Outside Max Angle

Measure from Character

Weight

Index [ 1 ]

Line Of Sight

Trace Channel

Visibility

Trace from View

Weight

Lock

Allow Lock

Lock Break Distance

2500

Lock Break Grace Seconds

1.0

Scan

Scan Radius

2000

Continuous Selection

Scan Interval

0.15

Scan Object Types

2 Array elements

Index [ 0 ]

Pawn

Index [ 1 ]

WorldDynamic

Target Teams

Enemies Only

Selection

Score Switch Margin

0.05

Engagement

Engaged Radius

Engaged Exit Radius

Engaged Linger Seconds

1.5

Engage Neutrals

Engaged Tag

UPC.State.Engaged

Multiplayer

Advanced

Max Reported Target Range

3000

Lock Switch

Switch Input Action

IA_UPC_Flick

Flick Activation Threshold

0.6

Flick Rearm Threshold

0.3

Switch Cooldown Seconds

0.25

Invert Flick X

Invert Flick Y

Flick Cone Half Angle Degrees

Max Switch Angle Degrees

Flick Direction Weight

0.35

Flick Proximity Weight

0.65

Lock Switch Score Policies

0 Array elements

The demo's Over Shoulder config. Engagement, Multiplayer and Lock Switch open with a click.

Its Score Policies decide who wins (Distance, View Angle, Input Direction and others, each with a Weight and an optional veto); see the Advanced drawer "The score policies". These settings shape the scan:

Setting	Does
Scan Radius	How far the scan looks, in centimeters; 2000 to start.
Scan Object Types	Collision object types the scan finds; Pawn to start, Pawn and WorldDynamic in the demo.
Continuous Selection, Scan Interval	Re-pick every Scan Interval (0.15 seconds), which a HUD marker following the target needs. Off to start: the component picks only when asked, by a lock press, an attack starting or Select Target Now.
Score Switch Margin	With Continuous Selection on, how much better, 0 to 1, a challenger must score to take the target; 0.05 stops flicker between two near-equal enemies. A pick made on demand ignores it.
Target Teams	Which teams the character may pick and lock (Leave teammates out).

Lock on

A lock holds one enemy as the target: scoring stops and the character carries UPC.State.LockedOn. The UPC Lock On Ability locks on one press and lets go on the next; the style decides how the camera follows (Camera).

A press locks the best candidate under the config's Lock Score Policies, or the soft target when that list is empty; a lock cone is a View Angle policy with its veto on and a tight angle. The soft target can be the nearer enemy at 40 degrees off the screen's center while a press under a 20-degree cone locks the one at 10 degrees. Allow Lock off turns lock-on off.

A lock lets go when its target dies, stops being targetable or joins a team Target Teams leaves out, or stays farther than Lock Break Distance (centimeters) for Lock Break Grace Seconds (1); the default Lock Break Distance of 0 turns that off.

Switch the lock with a flick

Set Switch Input Action to an Axis2D action (X screen-right, Y screen-up) in a mapping context active while locked, such as the demo's IA_UPC_Flick, and a flick moves the lock to the enemy that way. In Blueprint, Switch Lock Target switches in a direction of your own, Pick Flick Target previews the enemy a flick would reach, Lock Target locks an actor, Clear Lock lets go, and Is Locked and Get Locked Target read it.

Leave teammates out

Target Teams reads each actor's team from its UPC Team component. Enemies Only, the default, picks enemies and actors with no team; No Filter picks anyone; Friendlies Only picks teammates, for a heal; Neutral Only picks actors with no team, plus actors on a team you list under the character's UPC Team component's Exclusions: excluding team 2 makes team 2 actors count as neutral.

Put the UPC Team component on the pawn. UPC Character Base carries one as Team Component: set its Team Id. Until then the character is on no team, neutral to all sides, or takes its controller's team when the controller carries one (a UPC Team, or an AI controller's own team).

Know when a fight is on

Set Engaged Radius on the config, in centimeters, and the character carries Engaged Tag (UPC.State.Engaged) while an enemy is that close, for a combat camera, music or a HUD to follow. Only distance and team count, so an enemy behind a wall counts too. Unlike picking, engagement by default counts only an actor on a hostile team, so the character needs a team of its own. Tick Engage Neutrals to count actors with no team as well, such as the quick start's dummy. Engaged Exit Radius, above Engaged Radius, keeps an enemy pacing on the edge from flipping it; Engaged Linger Seconds (1.5) holds the tag after the last enemy leaves.

Read the target from a Blueprint

Node	Does
Get Current Target	The current target, or none; with Continuous Selection off, the last pick. Call Select Target Now first for a fresh one.
Try Get Current Target Point	True and the aim point while a target exists, for a HUD to read each frame.
On Target Changed, On Lock State Changed	Fire when the target changes, and when a lock is taken, moved or let go.
Is Actor Targetable, Resolve Target Point	Whether any character could target an actor, and where it would aim.

A transition branches on the target with Target State and Target Distance (Action Graph).

Debug it

UPC.Debug.Targeting 1, or Debug Overlay Targeting on one Targeting component, writes above the character who it fights and each candidate's score or the policy that dropped it. Log LogUPCTargeting Verbose logs the same per lock press.

AdvancedSelection in detail

Select Target Now runs at most one scan and one pick per frame. Refresh Candidates Now rescans at once, after a teleport or a wave spawning; Evaluate Now picks against the last scan. Neither waits for the once-a-frame limit.
A held lock, and engagement, rescan on Scan Interval with Continuous Selection off, so a flick sees enemies that came into range after the lock; engagement can end up to one Scan Interval late.
Keep a Distance policy's Max Distance without a veto at or above Scan Radius, so every scanned candidate keeps a usable rating.
Input Direction's resting rating of 1 still counts its Weight, softening the other policies' differences; lower its Weight to let them decide the resting pick.
Lock Target refuses the character itself, an untargetable actor, one Target Teams leaves out, and any lock with no config or Allow Lock off. Locking another actor while locked moves the lock.
Share Lock With Teammates tells teammates which enemy this character locks, through their own components' On Teammate Lock Changed and Get Teammate Locks, for a marker you draw.
Build Targeting Context is what a pick judges against: the character's location, eyes, camera view and last movement input. Override it in a child class of the Targeting component to aim from somewhere else, such as an aim-assist reticle.

AdvancedThe score policies

A candidate scores the average of its policies' ratings, each counted by its Weight; a policy at Weight 0 only vetoes, a pure filter. A tie goes to the nearer candidate, and with no policies the nearest wins.

Policy	Rates a candidate
Distance	Higher the closer, 0 at Max Distance (2000 cm). Veto Beyond Max Distance drops anything farther, so an attack aimed past it plays in place.
View Angle	Higher the nearer the view's center, 0 at Max Angle Degrees (90). Veto Outside Max Angle makes a hard cone; Measure from Character measures from the character along the camera's direction, leaving out an enemy behind its back.
Input Direction	Higher the nearer the stick's push, 0 at Max Angle Degrees (90); all rate 1 while the stick rests. With its veto, only an enemy in the pushed direction counts.
Aim Direction	Higher the nearer the aim (the stick when pushed, else the camera), 0 at Max Angle Degrees (45). Its veto starts on, so aiming at empty space picks no one.
Line Of Sight	Drops a candidate something blocks on Trace Channel (Visibility); Weight 0 to start. Trace from View traces from the camera, not the character's eyes.

In the demo, Freeflow rates Distance, Input Direction (Weight 2) and Line Of Sight; Over Shoulder rates Distance, Line Of Sight and View Angle measured from the character, each with its veto; Soulslike rates Distance (Weight 2), View Angle and Line Of Sight. The lock configs lock with View Angle and a Line Of Sight traced from the camera.

AdvancedFlick tuning

Setting	Does
Flick Activation Threshold	How far, 0 to 1, the stick must be pushed to switch; 0.6 ignores drift.
Flick Rearm Threshold	How far it must come back before the next flick counts; 0.3, so a stick held over switches once.
Switch Cooldown Seconds	The shortest gap between two switches; 0.25.
Invert Flick X, Invert Flick Y	Flip a direction for an action that runs the other way, such as inverted pitch.
Flick Cone Half Angle Degrees	How far off the flick an enemy may sit and still be picked; 60.
Max Switch Angle Degrees	How far across the screen from the current lock one flick may throw it; 90.
Flick Direction Weight, Flick Proximity Weight	Matching the flick's direction (0.35) against stepping to the enemy nearest the current lock on screen (0.65).
Lock Switch Score Policies	Extra policies for a switch only, such as a Line Of Sight veto.

AdvancedA score policy of your own

Create a Blueprint class whose parent is UPCTargetScorePolicy and override Score Candidate, returning 0 to 1, and Is Candidate Valid, returning false to veto. Both receive the Context (the character, where it stands and looks, the stick's direction) and the Candidate (the actor and its aim point). One policy object serves every character using the config, so read only the two inputs and keep no variables on the policy.

MultiplayerTargeting in multiplayer

Picking runs where the inputs live: on a player's own machine for a player, on the server for an AI. Other machines hold no targeting state for the character.
A player's machine tells the server its target and lock whenever either changes, so a transition condition or paired action on the server names the same enemy and holds the same lock. An attack carries its own target.
The server ignores a reported target beyond the config's Max Reported Target Range (3000 cm, under Multiplayer's advanced settings; 0 turns it off), or one the character may not target.
UPC.State.LockedOn sits on the player's machine and the server, each adding it from its own lock; UPC.State.Engaged only on the machine that picks the targets.
Targetable replicates: switch it on the server and every machine lets go of its lock.
The config does not replicate; set it on every machine, as a style's Targeting fragment on Every Machine does.
A controller does not reach other players' machines, so a character teamed only through its controller reads as teamless there; keep the UPC Team component on the pawn.
Share Lock With Teammates sends the server's lock to every machine showing the character; each machine hands it only to its own players on that team.

C++C++

UUPCTargetingComponent holds selection and lock; BuildTargetingContext is a BlueprintNativeEvent returning FUPCTargetingContext.
A score policy subclasses UUPCTargetScorePolicy and overrides ScoreCandidate_Implementation and IsCandidateValid_Implementation(const FUPCTargetingContext&, const FUPCTargetCandidate&).
UUPCTargetingComponent::ReleaseLocksOnActor(AActor*) makes every character locked onto an actor let go, for an actor with no Targetable component.
UUPCLockOnAbility::FallbackCamera is the UUPCStyleFragment_Camera the lock follows with when the style carries none.

AdvancedTroubleshooting

Symptom	Cause
The character picks nothing.	No config (a warning names it), no switched-on UPC Targetable, an object type outside Scan Object Types, or Target Teams leaves it out.
A lock press finds nothing.	Allow Lock is off, or the lock policies veto everything: an enemy outside the lock cone or behind cover.
The target flickers between two enemies.	Raise Score Switch Margin.
A HUD marker trails its enemy.	Tick Continuous Selection.

Validating a config warns on a Lock Break Distance below Scan Radius or an Engaged Exit Radius below Engaged Radius, and fails engagement with no Engaged Tag, no Scan Object Types, or a radius beyond Scan Radius.