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Line Trace By Channel

Official Documentation:


Trace a ray against the world using a specific channel and return the first blocking hit. Returns TRUE if a blocking hit is found.


Great to detect specific Actors, that the Line Trace hits, to for example deal Damage


// Optional: Define something, that you want to cast from e.g "Head" or a "Volume"
// CollisionVolume = CreateDefaultSubobject<USphereComponent>(TEXT("CollisionVolume"));
// CollisionVolume->SetupAttachment(RootComponent);

// In this example we'll implement the LineTrace inside the Tick
// but you can move the Code wherever you want
void AYourCharacter::Tick(float Deltatime)

// Define the parameters for the LineTrace
FHitResult Hit; // Stores the Hit-Result from the first blocking hit
// Getting the Forward Vector, where the Actor is currently facing
// and multipling it by 1000 units along the axis to define the End Point
FVector Forward = GetActorLocation()->GetForwardVector() * 1000.f;
// Get the Actors Location which will be our Starting point for the Trace
FVector Start = GetActorLocation();
FVector End = Start + Forward; // Combine both to have the full LineTrace
FCollisionQueryParams CollisionParams; // define the collision
CollisionParams.AddIgnoredActor(this); // add Actors to ignore, in this case this Actor
// if you want to ignore more Actors, just add the Line above again
// and add a different Actor Type inside the parantheses e.g: AddIgnoredActor(SomeActor::StaticClass())

if (Controller != nullptr) //check if the Controller is not null
// Call the LineTrace Function and provide the parameters we just defined
GetWorld()->LineTraceSingleByChannel(Hit, Start, End, ECC_Visibility, CollisionParams);
// To vizualize the LineTrace in-game, lets also draw a DebugLine:
DrawDebugLine(GetWorld(), Start, End, Hit.bBlockingHit ? FColor::Blue : FColor::Red, false, 5.0f, 1.0f, 10.0f);

// Check if something got hit and if the Actor is Valid
// You can also check for specific Actors e.g.:
// if (Hit.bBlockingHit && IsValid(Hit.GetActor()) && Hit.GetActor().IsA(AEnemy::StaticClass()))
if (Hit.bBlockingHit && IsValid(Hit.GetActor()))
// Do something with the Actor here
// Example:
AEnemy* Enemy = Cast<AEnemy>(Hit.GetActor());
if (Enemy)
Enemy->Health -= 10.f; // Damage
// if no actor got hit, you can do something here
// or just Log that nothing got got
UE_LOG(LogTemp, Log, TEXT("No Actor got got"));


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This was an example on how to use LineTraceSingleByChannel in Unreal Engine C++.