UProperty value not updating in construction script

Development Programming & Scripting
1

Hey I’m trying to get into procedural generation and ran into the following problem. I made a base class in c++ with a few UProperties to create a basic quad.

UCLASS( ClassGroup=(Custom), meta=(BlueprintSpawnableComponent) )
class PROCEDURALTERRAIN_API UTerrainGeneratorComponent : public UActorComponent
{
	GENERATED_BODY()
public:
	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	FVector GridOffset;
     
	UPROPERTY(EditAnywhere, BlueprintReadWrite)
	float CellSize;
private:
	class UProceduralMeshComponent* Mesh;
protected:
	UFUNCTION(BlueprintCallable)
	void GenerateGrid(FVector IGridOffset, float ICellSize);

....
};

The GenerateGrid function just creates a quad at the moment.

void UTerrainGeneratorComponent::GenerateGrid(FVector IGridOffset, float ICellSize)
{
	TArray<FVector> Vertices;
	TArray<int32> Triangles;
	TArray<FVector> Normals;
	TArray<FVector2D> UV0;
	TArray<FColor> VertexColors;
	TArray<FProcMeshTangent> Tangents;

	if (const AActor* Owner = GetOwner())
	{
		float VertexOffset = ICellSize * 0.5f;

		Vertices.Add(FVector(-VertexOffset, -VertexOffset, 0.f) + IGridOffset + Owner->GetActorLocation());
		Vertices.Add(FVector(-VertexOffset, VertexOffset, 0.f) + IGridOffset + Owner->GetActorLocation());
		Vertices.Add(FVector(VertexOffset, -VertexOffset, 0.f) + IGridOffset + Owner->GetActorLocation());
		Vertices.Add(FVector(VertexOffset, VertexOffset, 0.f) + IGridOffset + Owner->GetActorLocation());

		Triangles.Add(0);
		Triangles.Add(1);
		Triangles.Add(2);
		Triangles.Add(2);
		Triangles.Add(1);
		Triangles.Add(3);

		Mesh->CreateMeshSection(1, Vertices, Triangles, Normals, UV0, VertexColors, Tangents, true);

		UE_LOG(LogTemp, Warning, TEXT("[Terrain Generator]: Offset: %s"), *IGridOffset.ToString());
	}
}

I then made a blueprint based on an Actor and added the Component to it. The GenerateGrid function gets called in the ConstructionScript and in the event Graph with a custom event with Call in Editor set to true.

255989-error.png

The problem now is that changes made to the uproperties in the editor only work when called through the custom event. In the construction script the values are always 0 and therefore nothing visible is generated. Is this some kind of bug or am I doing something wrong?

2

this is old topic but if any needs an answer.
Construction script seems to be executed before setting component variables on instances. If you set’em in blueprint editor window(on archetype) then all works fine. Met same problem trying to debugdrawline with my custom spline, my uproperty checkbox “draw” just did nothing in constructionscript if set on instance, but works if set on archetype.
solution is to add those variables to actor itself and then pass it to function.

image
image1477×485 126 KB