Linetrace travels through objects/players

Development Programming & Scripting Blueprint
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1

After some debugging, it turns out the camera linetrace goes straight through objects, both worldstatics, worlddynamic, pawns, physics, collision boxes.

void ASWeapon::Fire()
{
	/*	Net Code 
	*	Dont let client apply damage
	*/
	if (Role < ROLE_Authority)
	{
		ServerFire();
	}

	/* Trace the world, from the pawn eyes to crosshair location */
	AActor* MyOwner = GetOwner();
	if (MyOwner)
	{
		/* Trace */
		FVector EyeLocation;
		FRotator EyeRotation;
		MyOwner->GetActorEyesViewPoint(EyeLocation, EyeRotation);

		/* Weapon Trace */
		FVector SocketLocation = MeshComponent->GetSocketLocation(MuzzleFireSocket);

		FVector ShotDirection = EyeRotation.Vector();
		FVector TraceEnd = EyeLocation + (ShotDirection * WeaponRange);

		FCollisionQueryParams QueryParams;
		QueryParams.AddIgnoredActor(MyOwner);
		QueryParams.AddIgnoredActor(this);
		QueryParams.bTraceComplex = true;
		QueryParams.bReturnPhysicalMaterial = true;

		FHitResult CameraHit;
		FHitResult GunHit;

		/* Particle "Target" parameter */
		EPhysicalSurface SurfaceType = SurfaceType_Default;
		
		/* Camera Trace */
		GetWorld()->LineTraceSingleByChannel(CameraHit, EyeLocation, TraceEnd, ECollisionChannel::ECC_Visibility, QueryParams);
		AActor* HitActor = CameraHit.GetActor();
		FVector ImpactPointCamera = CameraHit.ImpactPoint;

		GetWorld()->LineTraceSingleByChannel(GunHit, SocketLocation, ImpactPointCamera, ECollisionChannel::ECC_Visibility, QueryParams);
		AActor* HitActorGun = GunHit.GetActor();
		FVector ImpactPointGun = GunHit.ImpactPoint;

		SurfaceType = UPhysicalMaterial::DetermineSurfaceType(GunHit.PhysMaterial.Get());

		if (DebugWeaponDrawing > 0)
		{
			DrawDebugLine(GetWorld(), EyeLocation, TraceEnd, FColor::Red, true, -1.0f, 0, 1.0f);
			DrawDebugLine(GetWorld(), SocketLocation, ImpactPointGun, FColor::Blue, true, -1.0f, 0, 1.0f);
		}

		if (HitActor == HitActorGun)
		{
			/* Headshot */
			if (SurfaceType == SURFACE_FLESHVULNERABLE)
			{
				float CriticalDamage = BaseDamage * CriticalMultiplier;
				UGameplayStatics::ApplyPointDamage(HitActorGun, CriticalDamage, ShotDirection, GunHit, MyOwner->GetInstigatorController(), this, DamageType);
			}
			else if (SurfaceType == SURFACE_FLESHDEFAULT)
			{
				UGameplayStatics::ApplyPointDamage(HitActorGun, BaseDamage, ShotDirection, GunHit, MyOwner->GetInstigatorController(), this, DamageType);
			}
		}

		PlayImpactEffects(SurfaceType, ImpactPointGun);
		PlayFireEffects(ImpactPointGun);

		if (Role == ROLE_Authority)
		{
			HitScanTrace.TraceTo = ImpactPointGun;
			HitScanTrace.SurfaceType = SurfaceType;
		}

		LastFireTime = GetWorld()->TimeSeconds;
	}
}

256891-namnlos.png
256891-namnlos.png1208×577 250 KB

Red lines are cameratrace, blue lines are guntrace.

  • All objects in the scene are set to BLOCKALL, meshes and objects
  • It has been tested with different collision channels both custom and pre, same results.
  • Functionality is same on server/client.
2

The most likely reason your line trace is not registering a hit is because you are hitting something that does not have correct collision settings for that line trace channel. What are you trying to hit exactly, (that’s not registering)? Is it BSP shape, environment geometry, a character skeletal mesh? Because there is a few different reasons why a line trace would not hit different types of objects.

3

Thanks for the reply, after debugging a bit more it turns out the first trace goes straight through anything we aim at sometimes. I’ll edit the question to reflect.