UObject class in Unreal Engine

What class to select to fit the needs? How they differ each other and for what purpose are they intended?

Inheritance Hierarchy

Iterating over UObjects

The function below can be used for all Run-Time instances of UObject. Iterators in Unreal Engine are always accurate. More info about Iterators in the Iterators handbook

#include "EngineUtils.h"
void AExampleClass::PrintAllObjectsNamesAndClasses()
  for (TObjectIterator<UObject> Itr; Itr; ++Itr )
  • Object iterator is going to iterate over objects in the Pre-PIE world / the Editor World. This is not an issue when the game is running as an independent Game Instance / the editor is closed. Otherwise it can lead to unexpected results.
  • Object Iterator does not require a UWorld* Context - so Object Iterator is the way to get the proper context and access the entire living game world even when there's not possible to obtain the World().
  • UObject iterator can contain as well as iterate over all components that are inherited from this class, see Get Asset based of Class example. It can also iterate over TObjectIterator<AActor> Itr;, TObjectIterator<ACharacter> Itr; and others.

Get the names of all objects

#include "Kismet/BlueprintFunctionLibrary.h" // Engine
 * Get the names of all objects
 * @param bOutSuccess			If the action was a success or not
 * @param OutInfoMsg		More information about the action's result
 * @return Names of all the objects
UFUNCTION(BlueprintCallable, Category = "Alex Quevillon - Get All Actors Of Class")
static TArray<FString> GetNamesOfAllObjects(bool& bOutSuccess, FString& OutInfoMsg);
#include "Kismet/GameplayStatics.h" // Engine
#include "EngineUtils.h" // Engine
#include "Engine/StaticMeshActor.h" // Engine
TArray<FString> UExampleClass::GetNamesOfAllObjects(bool& bOutSuccess, FString& OutInfoMsg)
	// New list of names
	TArray<FString> Names = TArray<FString>();

	// Loop through all the objects using TObjectIterator
	// The class in <> is used as filter when getting the objects. This can be any class you want (as long as it's an Object)
	// In this case, we simply use the UObject class directly to get all the possible objects.
	// Also, for objects you don't need to specify a world as they're not only in a world. They're everywhere.
	// But that also means there are a lof of them, you probably want to filter the class you're looking for.
	for (TObjectIterator<UObject> It; It; ++It)
		// Get the real UObject from the Iterator
		UObject* Object = *It;

		// Get the Object's name

	// Return the names
	bOutSuccess = true;
	OutInfoMsg = FString::Printf(TEXT("Get Names Of All Objects Succeeded"));
	return Names;

Get Asset based of Class

As UObject is a class from which many Classes is inherited, it may be used for a parameter that allow to transfer any type of its inherited assets, see the code below:

#include "Engine/StaticMesh.h" // Engine
#include "Engine/SkeletalMesh.h" // Engine
#include "Engine/Texture.h" // Engine
#include "Animation/AnimSequence.h" // Engine
#include "Engine/DataTable.h" // Engine
#include "Sound/SoundWave.h" // Engine
UAssetImportData* UExampleClass::GetAssetImportData(UObject* Asset)
  if (Cast<UStaticMesh>(Asset) != nullptr) // UStaticMesh
    return Cast<UStaticMesh>(Asset)->AssetImportData;
  else if (Cast<USkeletalMesh>(Asset) != nullptr) // USkeletalMesh
    return Cast<USkeletalMesh>(Asset)->GetAssetImportData();
  else if (Cast<UTexture>(Asset) != nullptr) // UTexture
    return Cast<UTexture>(Asset)->AssetImportData;
  else if (Cast<UAnimSequence>(Asset) != nullptr) // UAnimSequence
    return Cast<UAnimSequence>(Asset)->AssetImportData;
  else if (Cast<UDataTable>(Asset) != nullptr) // UDataTable
    return Cast<UDataTable>(Asset)->AssetImportData;
  else if (Cast<USoundWave>(Asset) != nullptr) // USoundWave
    return Cast<USoundWave>(Asset)->AssetImportData;
  // .. any other asset type inherited from UObject
  return nullptr;