ConstructorHelpers::FObjectFinder<UMaterialParameterCollection>

Development Programming & Scripting C++
1

Hey, I’m trying to get a hold of a MaterialParameterCollection in C++. Here is the code I am using:


	
static ConstructorHelpers::FObjectFinder<UMaterialParameterCollection> MaterialCol(TEXT("MaterialParameterCollection'/Game/Characters/Materials/RoxyBody'"));
	if (MaterialCol.Succeeded())
	{
		BodyMaterialCollection = reinterpret_cast<UMaterialParameterCollection*>(MaterialCol.Object);
	}

However I get the following error on compilation



Severity	Code	Description	Project	File	Line	Suppression State
Error	C2664	'void ConstructorHelpers::ValidateObject(UObject *,const FString &,const TCHAR *)': cannot convert argument 1 from 'UMaterialParameterCollection *' to 'UObject *'	DarklightProject	C:\Program Files (x86)\Epic Games\4.12\Engine\Source\Runtime\CoreUObject\Public\UObject\ConstructorHelpers.h	105

UMaterialParameterCollection inherits from UObject, so I have no idea why it is not able to convert it.

2

You shouldn’t need to cast the object at all, just use BodyMaterialCollection = MaterialCol.Object.

Bear in mind, you can’t change any properties of that collection asset. Each world creates an instance of a material parameter collection, and you should instead modify that instance. See UKismetMaterialLibrary for more details.

3

I have same issue and your suggestion @ TheJamsh didn’t fix it.
Code in constructor:

static ConstructorHelpers::FObjectFinder<UMaterialParameterCollection> objectType(TEXT("/Script/Engine.MaterialParameterCollection'/Game/ThirdPerson/Blueprints/MPC_01.MPC_01'"));
if (objectType.Succeeded()){
    collection = objectType.Object;
    UE_LOG(LogTemp, Warning, TEXT("	ktx ---- AChar_A >>   Material Parameter Collection found"));
}

… and error:

1>C:\Program Files\Epic Games\UE_5.1\Engine\Source\Runtime\CoreUObject\Public\UObject\ConstructorHelpers.h(110): error C2664: ‘void ConstructorHelpers::ValidateObject(UObject *,const FString &,const TCHAR *)’: cannot convert argument 1 from ‘T *’ to ‘UObject *’

… any suggestion?

This is how i fixed it in 5.1:

inside constructor - MPC_A is a public pointer variable of UMaterialParameterCollection

MPC_A = Cast<UMaterialParameterCollection>(StaticLoadObject(UMaterialParameterCollection::StaticClass(), nullptr, TEXT("/Script/Engine.MaterialParameterCollection'/Game/ThirdPerson/Blueprints/MPC_01.MPC_01'")));

you have to include these in header file:

include “Materials/MaterialParameterCollection.h”
include “Materials/MaterialParameterCollectionInstance.h”
include “Kismet/KismetMaterialLibrary.h”

… access parameters inside other functions/methods

UKismetMaterialLibrary::SetScalarParameterValue(GetWorld(), MPC_A, "mpc01_svar_01", 7.0);
UKismetMaterialLibrary::SetVectorParameterValue(GetWorld(), MPC_A, "mpc01_vvar_01", FLinearColor::Blue);