Data Assets¶

A Data Asset is a UObject asset that holds only data — no logic. Use it to encode tunable values, configurations, item definitions, etc.

Three flavors¶

Class	When to use
`UDataAsset`	Simple data container
`UPrimaryDataAsset`	Identified by `FPrimaryAssetId`; loadable via Asset Manager
`UDataTable`	Tabular data, importable from CSV / JSON

UDataAsset¶

UCLASS(BlueprintType)
class MYGAME_API UItemData : public UDataAsset
{
    GENERATED_BODY()
public:
    UPROPERTY(EditAnywhere) FText DisplayName;
    UPROPERTY(EditAnywhere) UTexture2D* Icon;
    UPROPERTY(EditAnywhere) int32 MaxStack = 1;
};

Create instances via right-click → Miscellaneous → Data Asset → choose your class.

UPrimaryDataAsset¶

Identifies an asset by ID across the project — used by Asset Manager for async loading.

UCLASS(BlueprintType)
class MYGAME_API UItemDefinition : public UPrimaryDataAsset
{
    GENERATED_BODY()
public:
    virtual FPrimaryAssetId GetPrimaryAssetId() const override
    {
        return FPrimaryAssetId(TEXT("Item"), GetFName());
    }
};

Register the type in Project Settings → Asset Manager → PrimaryAssetTypesToScan:

Primary Asset Type: Item
Asset Base Class:   /Script/MyGame.ItemDefinition
Directories:        /Game/Items

Then async-load by ID:

TArray<FPrimaryAssetId> Ids = { FPrimaryAssetId(TEXT("Item.Sword_01")) };
UAssetManager::Get().LoadPrimaryAssets(Ids, {}, FStreamableDelegate::CreateUObject(this, &Mine::OnLoaded));

UDataTable¶

Tabular. Author rows in CSV/JSON, import as a table:

USTRUCT(BlueprintType)
struct FEnemyStats : public FTableRowBase
{
    GENERATED_BODY()
    UPROPERTY(EditAnywhere) FName Id;
    UPROPERTY(EditAnywhere) int32 Health;
    UPROPERTY(EditAnywhere) float Speed;
};

Import → choose FEnemyStats as the row struct → rows show in the table editor.

Access:

FEnemyStats* Row = MyTable->FindRow<FEnemyStats>(TEXT("Goblin"), TEXT(""));

When to use which¶

Need	Use
One-off config	`UDataAsset`
Many instances, async-loaded by ID	`UPrimaryDataAsset` + Asset Manager
Spreadsheet-shaped data	`UDataTable`
Designer-friendly editing of arrays	`UPrimaryDataAsset` with `TArray` properties
Hot-reload from CSV during dev	`UDataTable`

Gotchas¶

Data Assets cannot have BP-only properties without packaging quirks; declare in C++.
Asset Manager scans happen at startup — large projects can take 5–10 s; set scan directories tightly.
DataTables are not great for hierarchical data; nest with structs but expect editor friction.