Overlap trigger: detect player entering a zone and do something once

Pattern: EventActorBeginOverlap → CastTo<BP_Character>(Object=OtherActor) → Cast Succeeded → DoOnce → [your action here]. Key pins: EventActorBeginOverlap outputs 'OverlappedActor' and 'OtherActor'. CastTo input is 'Object', exec outputs are 'Cast Succeeded' and 'Cast Failed'. DoOnce exec output is 'Completed'.

Line trace from camera to detect what player is looking at

Pattern: GetPlayerController → GetPlayerViewPoint(outputs Location,Rotation) → GetForwardVector(Rotation) → Multiply_VectorFloat(A=Forward, B=TraceDistance) → Add_VectorVector(A=CameraLocation, B=Offset) → LineTraceByChannel(Start=CameraLocation, End=TraceEnd). GetPlayerViewPoint exec in='execute', exec out='then', outputs: 'Location' (Vector) and 'Rotation' (Rotator).

Mouse click to world: detect clicked actor or ground position

On Left Mouse Button pressed → GetHitResultUnderCursorByChannel(TraceChannel=Visibility) → Branch(ReturnValue=true) → BreakHitResult → Check HitActor: IsValid(HitActor) → Branch → True: interact with HitActor. Check ground: use ImpactPoint as the world position clicked. GetHitResultUnderCursorByChannel is on PlayerController. Inputs: 'TraceChannel' (ETraceTypeQuery) and 'bTraceComplex' (bool). Output: 'HitResult' (struct) and 'ReturnValue' (bool). Use BreakHitResult to get ImpactPoint, HitActor, etc.

EventHit — fires when actor is hit by or hits something

Requires Simulation Generates Hit Events on physics body.

Pressure plate trigger that activates when enough weight is on it

Pattern: BoxCollision trigger, variable OverlappingActors(int)=0. OnBeginOverlap: OverlappingActors++ → Branch(OverlappingActors >= RequiredCount) → Activate. OnEndOverlap: OverlappingActors-- → Branch(OverlappingActors < RequiredCount) → Deactivate. Use interface or event dispatcher to notify connected actors (doors, platforms).

RandomBool — return random true or false

Greater_FloatFloat — check if A greater than B

Array Contains — check if array contains a specific element

Pure node. Input pin is 'Item To Find In Array' (includes spaces).

OnComponentHit — hit event on specific component

Pickup and collectible system with overlap trigger

Pattern: Pickup actor with SphereCollision(overlap), StaticMesh visual. OnComponentBeginOverlap → CastTo PlayerCharacter → Success: call AddScore/AddItem interface on player → PlaySoundAtLocation → SpawnEmitterAtLocation → DestroyActor(self). Set collision to OverlapOnlyPawn for performance.