Why does my LineTraceByChannel return no hit even when geometry is in front?

Either the trace starts inside your own collider (self-hit ignored, pass through), Start/End are in component-local space when LineTrace expects world, or the collision channel response is wrong. Use world-space coords and pass IgnoredActors.

How do I trace forward from a component?

FVector Start = Comp->GetComponentLocation(); FVector End = Start + Comp->GetForwardVector() * Distance; world-space, ready for LineTraceByChannel.

Should I ignore the actor or component?

FCollisionQueryParams Params; Params.AddIgnoredActor(GetOwner()); excludes any collider on the same actor. AddIgnoredComponent for finer control.

Fix: Unreal LineTraceByChannel from Component Returns No Hit

Quick answer: Build Start and End in world space (GetComponentLocation + GetForwardVector * Distance). Pass an FCollisionQueryParams with AddIgnoredActor(GetOwner()). Verify the trace channel response on potential targets.

Player’s muzzle component runs LineTraceByChannel forward. Bullets pass through enemies. Trace starts inside the player’s capsule and self-ignores; geometry beyond is missed.

The Symptom

OutHit is empty even when geometry visibly sits in front of the trace path.

The Fix

UMuzzleComponent* Muzzle = ...;
FVector Start = Muzzle->GetComponentLocation();
FVector End   = Start + Muzzle->GetForwardVector() * 5000.0f;

FCollisionQueryParams Params;
Params.AddIgnoredActor(GetOwner());
Params.bTraceComplex = false;

FHitResult Hit;
bool bHit = GetWorld()->LineTraceSingleByChannel(
    Hit, Start, End, ECC_Weapon, Params);

DrawDebugLine(GetWorld(), Start, End, bHit ? FColor::Red : FColor::Green, false, 0.1f);

if (bHit) UE_LOG(LogTemp, Log, TEXT("Hit %s"), *Hit.GetActor()->GetName());

World-space coords. Self-actor ignored. Debug line shows the trace; red = hit, green = miss.

Trace Channel

ECC_Weapon (or your custom channel) must be configured per target as Block. Wall has Weapon = Block. Enemy capsule has Weapon = Block. See related post for collision channels.

Verifying

Run with DrawDebugLine. Confirm visually the trace starts at the muzzle and ends where you expected. Hit = red where geometry is.

“World coords. Ignore self. Right channel response. Hit lands.”

Related Issues

For collision channel response, see trace response. For Replication Graph, see replication.

World space. Ignore self. Hits land.