Spawn an Actor without collision

Development World Creation
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1

I read much posts about removing collision from Actors, but none of them worked for me. I’m trying to have a Box, where you can walk through, but I’m stucking at removing the collision. My current constructor code is:

{
 	// Set this actor to call Tick() every frame.  You can turn this off to improve performance if you don't need it.
	PrimaryActorTick.bCanEverTick = true;

	// Add Box
	CollisionComp = CreateDefaultSubobject<UBoxComponent>(TEXT("CubeComp"));

	// Set as root component
	RootComponent = CollisionComp;
	this->SetActorEnableCollision(false);
}
2

Could you try

CollisionComp->SetCollisionEnabled(ECollisionEnabled::NoCollision);

and see if it changes anything?

3

Thx, but doesn’t work for me. I think there is a preset that defines the collision:
For making this actor I did this:

  1. Create actor class
  2. Added a box
    CollisionComp = CreateDefaultSubobject(TEXT(“CubeComp”));
  3. Tryed to remove collision the constructor.

So actually what I’m trying to do is a Trigger: If a player enters a certain area, a function should being be called. Am I doing wrong like this? Is there maybe another better way to do this?

4

Hello Snoat,

From your one comment it sounds like you are trying to make a trigger but not a hard collision correct? This is how I have been making trigger effects (my example will use a sphere component because I can pull it from code that I know works)

//SETUP SPHERE

pDetectionSphere = CreateDefaultSubobject<USphereComponent>(TEXT("FishSphere"));
pDetectionSphere->SetupAttachment(RootComponent);
pDetectionSphere->SetSphereRadius(DetectionRadius);
pDetectionSphere->OnComponentBeginOverlap.AddDynamic(this, &ANpcFish::OnOverlapBegin);
pDetectionSphere->bGenerateOverlapEvents = true;

ANpcFish is the class. This makes it so that characters can walk through the sphere (which is invisible) and trigger it if they also allow overlap events (which is just a check box in a collision component). Then you define the functionality you want in the OnOverlapBegin(…)

The definition looks like this :

UFUNCTION()
void ANpcFish::OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult)
{

// your functionality when something overlaps this; this example checks to see if the player overlapped with
//my sphere. If so remove the sphere component because I only want this to trigger once.

//if collision was on the detection sphere
USphereComponent* pSphere = Cast<USphereComponent>(OverlappedComp);

//returns null if other actor is not player fish
APlayerFish* pPlayer = Cast<APlayerFish>(OtherActor);

//player hit our detection sphere, no longer need the sphere. Sets to nullptr automatically.
if (pPlayer && pSphere)
{
    pSphere->DestroyComponent();
}
}

This also needs to be in your header file like this

UFUNCTION()
void OnOverlapBegin(class UPrimitiveComponent* OverlappedComp, class AActor* OtherActor, class UPrimitiveComponent* OtherComp, int32 OtherBodyIndex, bool bFromSweep, const FHitResult& SweepResult);

The UFUNCTIION() above both of these is an important macro. It has to be there. This is a link to a really quick tutorial in the documentation using c++ only: CPP Only Example | Unreal Engine 5.1 Documentation

Hopefully this helps! Remember that this sets the component to generate overlap events but those will only trigger with other actors/objects that also generate overlap events! Hopefully the wall o’ text isn’t so bad!

5

Thank you so much for your so detailed explaination, now everything works! I tryed to get it working for some days but still stucked somewhere. And also thx for telling me the thing with UFUNCTION(), without you I never would have figured it out :slight_smile: