Object finder: cannot convert 'UStaticMesh ' to 'UObject '

Development Programming & Scripting
1

The error in the output log:

error C2664: 'void
ConstructorHelpers::ValidateObject(UObject
*,const FString &,const TCHAR *)': cannot convert argument 1 from
'UStaticMesh *' to 'UObject *'
Line 109 in ConstructorHelpers.h: ValidateObject( Object, PathName, ObjectToFind );

The code in the constructor:

	static ConstructorHelpers::FObjectFinder<UStaticMesh>meshAsset(TEXT("/Game/Meshes/SM_MinePickaxeB_01")); // <<< error for this line
StaticMeshComp->SetStaticMesh(meshAsset.Object);

I also tried my own function but that one gave the exact same error:

// cpp constructor call
StaticMeshComp->SetStaticMesh(ULib::CreateObject<UStaticMesh>("/Game/Meshes/SM_MinePickaxeB_01"));

// static function

	template <typename Type>
	static Type* CreateObject(FString Path)
	{
		Type* Temp = nullptr;
		Temp = ConstructorHelpers::FObjectFinderOptional<Type>(*Path).Get();

        #if WITH_EDITOR
		  if (Temp == nullptr) { UE_LOG(LogTemp, Error, TEXT("%s"), *Path) }
        #endif

		return Temp;
	}

It compiled before but I added literally 1 line to the cpp file:

WeaponAnimType = EWeaponAnimType::Pistol; // TODO: Use pickaxe animation.

and ever since I can’t get it to compile anymore… Not even when I outcomment that newly added line. What am I doing wrong?

2

So eventually I outcommented it all in a desperate way to get the project to compile and then this happened:

That’s literally 3 compiler errors in a row for 1 (outcommented) line of code. That’s really bad…

221995-seriously.png
221995-seriously.png1481Ă—864 63.3 KB

I cleaned the project AGAAAAAAAAAAAIN and now it compiles. Of course without any mesh assigned but hell, at least the project compiles. What is going on…

3

Apparently the compiler expects an UObject. UStaticMesh* is an object but… Pressing F12 on UStaticMesh* brings me to a forward declaration in Engine.h. So the compiler does not (yet) know that this in fact is an UObject.

Solution (yes it’s very simple):

#include "Engine/StaticMesh.h"

Of course the question still remains: Why did it compile prior to adding this nonsense line:

 WeaponAnimType = EWeaponAnimType::Pistol; // TODO: Use pickaxe animation.

And why does it also not compile anymore when I hit ctrl+z until it reverts back to the original state? It still does not compile even though the code is now EXACTLY THE SAME as when it used to compile. BUT when I use SourceControl to revert the exact same change, then it compiles. So even though I found the problem and solved it, there is something much more nasty going on somewhere (and I still suspect a UE4-related bug). If someone figures this out some day, please let me know!

1 Like
4

I spent a day trying to solve this problem. Error message is not informative and Visual Studio doesn’t warn me about adding that header file. Now it works, thank you!