UKismetSystemLibrary::LineTraceMulti

function Engine Blueprint Since 4.0

#include "Kismet/KismetSystemLibrary.h"

Access: public Specifiers: staticUFUNCTIONBlueprintCallable

Description

Performs a line trace between Start and End against the given Trace Channel and returns every hit up to and including the first blocking hit. Exposed to Blueprint as 'Multi Line Trace By Channel'.

Caveats & Gotchas

• If the segment never encounters a blocking hit, OutHits contains every overlapping hit for the entire Start-to-End segment, not just up to some implicit range limit.
• TraceChannel-based like LineTraceSingle — pass a Trace Channel, not an Object Type; use LineTraceMultiForObjects for Object Type queries.
• DrawDebugType is compiled out entirely in shipping builds (guarded by ENABLE_DRAW_DEBUG).

Signature

static ENGINE_API bool LineTraceMulti(const UObject* WorldContextObject, const FVector Start, const FVector End, ETraceTypeQuery TraceChannel, bool bTraceComplex, const TArray<AActor*>& ActorsToIgnore, EDrawDebugTrace::Type DrawDebugType, TArray<FHitResult>& OutHits, bool bIgnoreSelf, FLinearColor TraceColor = FLinearColor::Red, FLinearColor TraceHitColor = FLinearColor::Green, float DrawTime = 5.0f)

Parameters

Name	Type	Description	Default
WorldContextObject	const UObject*	Object used to resolve which UWorld to run the trace in.	—
Start	const FVector	Start point of the trace in world space.	—
End	const FVector	End point of the trace in world space.	—
TraceChannel	ETraceTypeQuery	Trace Channel to test against (Project Settings > Collision > Trace Channels).	—
bTraceComplex	bool	True to test against per-poly complex collision, false to test against simplified collision.	—
ActorsToIgnore	const TArray<AActor*>&	Actors excluded from the trace.	—
DrawDebugType	EDrawDebugTrace::Type	Debug draw mode for visualizing the trace.	—
OutHits	TArray<FHitResult>&	All hits found along the segment, up to and including the first blocking hit.	—
bIgnoreSelf	bool	If true, ignores the actor owning WorldContextObject.	—
TraceColor	FLinearColor	Color used to draw the non-hit portion of the trace when debug drawing is enabled.	FLinearColor::Red
TraceHitColor	FLinearColor	Color used to draw from the hit point onward when debug drawing is enabled.	FLinearColor::Green
DrawTime	float	How long the debug draw persists, in seconds.	5.0f

Return Type

bool

Example

Trace forward and collect every hit up to the first block C++

TArray<FHitResult> Hits;
TArray<AActor*> ActorsToIgnore;
ActorsToIgnore.Add(this);

const FVector Start = GetActorLocation();
const FVector End = Start + GetActorForwardVector() * 1000.f;

bool bHit = UKismetSystemLibrary::LineTraceMulti(this, Start, End, UEngineTypes::ConvertToTraceType(ECC_Visibility), false, ActorsToIgnore, EDrawDebugTrace::ForDuration, Hits, true);

Version History

Introduced in: 4.0

Version	Status	Notes
5.6	stable	—

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