UWorld::LineTraceSingleByChannel

function Engine Since 4.0

#include "Engine/World.h"

Access: public Specifiers: const

Description

Traces a ray from Start to End using the specified collision channel and returns the first blocking hit. Returns true if a blocking hit was found.

Signature

bool LineTraceSingleByChannel( struct FHitResult& OutHit, const FVector& Start, const FVector& End, ECollisionChannel TraceChannel, const FCollisionQueryParams& Params = FCollisionQueryParams::DefaultQueryParam, const FCollisionResponseParams& ResponseParam = FCollisionResponseParams::DefaultResponseParam ) const

Parameters

Name	Type	Description	Default
OutHit	struct FHitResult&	Receives the first blocking hit. Only valid when the function returns true.	—
Start	const FVector&	World-space start point of the ray.	—
End	const FVector&	World-space end point of the ray.	—
TraceChannel	ECollisionChannel	Collision channel that determines which components are considered blocking hits.	—
Params	const FCollisionQueryParams&	Additional query options: ignored actors, complex collision, draw debug, etc.	FCollisionQueryParams::DefaultQueryParam
ResponseParam	const FCollisionResponseParams&	Override collision response settings for this trace.	FCollisionResponseParams::DefaultResponseParam

Return Type

bool

Caveats & Gotchas

• The owning actor is not automatically excluded — call Params.AddIgnoredActor(this) to prevent the trace from hitting the actor performing it.
• OutHit data is only meaningful when the function returns true. OutHit.GetActor() will return null on a miss.
• To capture all overlapping hits along the ray (not just the first blocker), use LineTraceMultiByChannel instead.

Example

Raycast forward from the camera C++

FHitResult Hit;
FVector Start = Camera->GetComponentLocation();
FVector End   = Start + Camera->GetForwardVector() * 5000.f;

FCollisionQueryParams Params;
Params.AddIgnoredActor(this);

if (GetWorld()->LineTraceSingleByChannel(Hit, Start, End, ECC_Visibility, Params))
{
	AActor* HitActor = Hit.GetActor();
}

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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