World vs Inventory Items

FItemInstance ItemInstance;     // The item data
bool bIsInfinite;               // Infinite pickup (for demos)
float DespawnTime;              // Auto-despawn timer (0 = never)
UStaticMeshComponent* MeshComponent;  // Visual representation

1. Drag WorldItemActor into level
2. Set ItemInstance properties manually
3. Or call InitializeFromInstance() with a pre-made instance

// Blueprint or C++
AWorldItemActor* WorldItem = GetWorld()->SpawnActor<AWorldItemActor>(
    AWorldItemActor::StaticClass(),
    SpawnLocation,
    SpawnRotation
);

WorldItem->InitializeFromInstance(ItemInstance);

InventoryComponent->SpawnWorldItem(ItemInstance, DropLocation);

DespawnTime = 0.0    → Never despawns
DespawnTime = 60.0   → Despawns after 60 seconds
DespawnTime = 300.0  → Despawns after 5 minutes

bIsInfinite = true;

• Demo/tutorial items
• Respawning resource nodes
• Testing

​

Inventory Items

1. Pickup: WorldItemActor → FItemInstance (added to inventory)
2. Storage: FItemInstance exists in InventoryComponent
3. Drop: FItemInstance → WorldItemActor (spawned in world)

​

Transitioning Between States

// InteractionComponent triggers this
InventoryComponent->AddItemInstance(WorldItem->ItemInstance);
WorldItem->Destroy();

// Drop item at player's feet
FVector DropLocation = PlayerCharacter->GetActorLocation() +
                       PlayerCharacter->GetActorForwardVector() * 100;

InventoryComponent->SpawnWorldItem(ItemInstance, DropLocation);
InventoryComponent->RemoveItemByID(ItemInstance.ItemID, Quantity);

​

Best Practices

• Use sparingly (each is an actor)
• Set despawn timers in survival games
• Use object pooling for frequently spawned items
• Consider LOD for distant items

• Preferred for storage (lightweight)
• Use for player inventory, containers, vendors
• Batch operations when possible
• Validate before adding

​

Container Items

Chest Actor
└── InventoryComponent
    ├── Slot 0: Iron Sword x1
    ├── Slot 1: Health Potion x5
    └── Slot 2: Gold Ore x20

1. Player UI shows the chest’s InventoryComponent
2. Player can transfer items between their inventory and the chest
3. Items remain as FItemInstance throughout (no world spawning needed)

​

Summary

• Item IDs uniquely identify item types
• ItemDataAsset defines what an item type is (the template)
• FItemInstance represents a specific instance with unique properties
• Stacking Policies control how items merge based on their characteristics
• World Items are physical actors in the world
• Inventory Items are lightweight structs stored in components