SplineComponent in TArray

Development Programming & Scripting C++
, , , , , ,
1

I Have no idea why I can’t edit the SplineComponent in Editor.
I have simple ActorComponent :

ULBranchActorComponent .h

UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )
class MGR_API ULBranchActorComponent : public UActorComponent
{
	GENERATED_BODY()

public:	
	// Sets default values for this component's properties
	ULBranchActorComponent();

	// Called when the game starts
	virtual void BeginPlay() override;
	
	// Called every frame
	virtual void TickComponent( float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction ) override;
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "LTree-BranchComponent")
	class USplineComponent*	m_thisBranch;
		
	
};

ULBranchActorComponent.cpp

ULBranchActorComponent::ULBranchActorComponent()
{
	// Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features
	// off to improve performance if you don't need them.
	bWantsBeginPlay = true;
	PrimaryComponentTick.bCanEverTick = true;

	 m_thisBranch = CreateDefaultSubobject<USplineComponent>(TEXT("branch"));
	m_thisBranch->Activate(true);
	m_thisBranch->bSplineHasBeenEdited = true;
	m_thisBranch->MarkRenderStateDirty();
	m_thisBranch->SetRelativeLocation(FVector(0, 0, 0));
	// ...
}

Then in Actor LTree i have :

UPROPERTY(EditDefaultsOnly, BlueprintReadWrite, Category = "LTree")
 TArray<class ULBranchActorComponent *>m_Branch;

And when I want to add a ULBranchActorComponent i call this :

ULBranchActorComponent *branch = NewObject<ULBranchActorComponent>(this, TEXT("branch"));
branch->m_thisBranch->Activate(true);
branch->m_thisBranch->bSplineHasBeenEdited = true;
branch->m_thisBranch->MarkRenderStateDirty();
m_Branch.Add(branch);

And in Editor I can’t edit those splines, like normal spline so left click and context menue.

I have changed the SplineComponent.h with this Spline not editable when set in Construction Script - Blueprint - Unreal Engine Forums.

So when i have single SplineComponent NOT ULBranchcomponent I’m able to edit this spline. But I want to have multiple splines in one Actor.

2

Hey MenosGrandes-

There is an open bug about not being able to edit or add nodes to an array of splines created in code (UE-14064). If you are trying to have multiple splines then the best option currently is to do so through blueprints.

Cheers

3

Could you give any tips how to do this in bp?
When I’m adding a dynamic spline, simply using AddSplineComponent the Spline does’nt show up. Only when I have SplineComponent added by the big green button “+Add component”. But I don’t know how much Splines i will need.

4

Hey MenosGrandes-

I apologize for the delayed response. I did not realize you were attempting to add spline components dynamically. Unfortunately this is not a feature that is available. What exactly are you trying to accomplish? Depending on what the end goal is there may be another way around using dynamic splines.

5

“Unfortunately this is not a feature that is available.”
But what’s the ‘Add Spline Component’ node in the blueprint for?

6

The “Add Spline Component” node can be used to add a spline during runtime. MenosGrandes is attempting to add splines to his actor that can be edited in the editor outside of runtime.

7

From 2022, I am also trying to add multiple splines to a blueprint in the editor for some tooling I am making. I have a blueprint that would be best as a single blueprint with multiple splines - I’m making modular train tracks on a spline using instanced static mesh components, and I want to have multiple disconnected tracks running on the same ISMC’s.

This is a ‘call in editor’ function that does add a spline to the array (I can see it in the public array value when I click the call in editor button), but I can’t see the spline in the editor viewport, and I can’t see the spline component in the instantiated blueprint’s component hierarchy in the details panel:

image
image1719×433 137 KB