UWorld::SweepSingleByChannel

function Engine Since 4.0

#include "Engine/World.h"

Access: public Specifiers: const

Description

Sweeps a collision shape from Start to End and returns the first blocking hit. More accurate than a line trace when testing whether a volume (capsule, sphere, or box) can pass through space.

Signature

bool SweepSingleByChannel( struct FHitResult& OutHit, const FVector& Start, const FVector& End, const FQuat& Rot, ECollisionChannel TraceChannel, const FCollisionShape& CollisionShape, const FCollisionQueryParams& Params = FCollisionQueryParams::DefaultQueryParam, const FCollisionResponseParams& ResponseParam = FCollisionResponseParams::DefaultResponseParam ) const

Parameters

Name	Type	Description	Default
OutHit	struct FHitResult&	Receives the first blocking hit result.	—
Start	const FVector&	World-space start position of the swept shape's center.	—
End	const FVector&	World-space end position of the swept shape's center.	—
Rot	const FQuat&	Rotation of the swept shape. Use FQuat::Identity for no rotation.	—
TraceChannel	ECollisionChannel	Collision channel determining which components can be hit.	—
CollisionShape	const FCollisionShape&	The shape to sweep. Create with FCollisionShape::MakeSphere(), MakeCapsule(), or MakeBox().	—
Params	const FCollisionQueryParams&	Additional query options.	FCollisionQueryParams::DefaultQueryParam
ResponseParam	const FCollisionResponseParams&	Override collision response settings.	FCollisionResponseParams::DefaultResponseParam

Return Type

bool

Caveats & Gotchas

• Use FCollisionShape::MakeSphere(Radius), MakeCapsule(Radius, HalfHeight), or MakeBox(HalfExtents) to construct the shape — there is no useful default constructor.
• FQuat::Identity is the correct value for Rot when shape orientation doesn't matter (spheres) or when you want an axis-aligned sweep.
• Sweep queries are more expensive than line traces. Cache FCollisionShape and FCollisionQueryParams if calling this frequently per frame.

Example

Sphere sweep forward to check for obstacles C++

FHitResult Hit;
FCollisionShape Sphere = FCollisionShape::MakeSphere(30.f);
FCollisionQueryParams Params;
Params.AddIgnoredActor(this);

bool bBlocked = GetWorld()->SweepSingleByChannel(
	Hit,
	GetActorLocation(),
	GetActorLocation() + GetActorForwardVector() * 500.f,
	FQuat::Identity,
	ECC_Pawn,
	Sphere,
	Params
);

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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