> ## Documentation Index
> Fetch the complete documentation index at: https://docs.warpathstudios.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Item Instances

> While defines the type of item, represents a specific instance of that item with unique properties.

While `ItemDataAsset` defines the **type** of item, `FItemInstance` represents a **specific instance** of that item with unique properties.

**Location**: `/Public/Inventory/Structures/ItemInstance.h`

### **The Difference**

Think of it like this:

* **ItemDataAsset** = "The concept of an Iron Sword"
* **FItemInstance** = "Bob's Iron Sword with 75% durability that he crafted on Tuesday"

### **FItemInstance Structure**

```
FName ItemID;                              // Which item type
int32 Quantity;                            // Stack size
UItemDataAsset* ItemData;                  // Reference to definition
FGameplayTag RarityTag;                    // Instance rarity
TArray<FStatModifier> StatModifiers;       // Custom stats
FText CrafterName;                         // Who crafted this
TArray<FItemModSlot> Infusions;            // Mods/enchantments
float Durability;                          // Current durability
FDateTime CreationTime;                    // When created
FGuid UniqueID;                            // Globally unique ID
FName OwnerID;                             // Ownership tracking
```

### **Key Properties Explained**

**ItemID & ItemData**

* **ItemID**: Quick reference to item type
* **ItemData**: Full reference to the ItemDataAsset
* Both are kept for performance (ID is faster to check, Data has all info)

**Quantity**

* How many items in this stack
* Must be ≤ ItemData's MaxStackSize
* Used for commodities, ammo, resources

**Rarity Tag**

* Can override the ItemDataAsset's default rarity
* Allows the same sword to drop as Common or Epic
* Used by loot system for random quality

**Stat Modifiers**

* Additional stats beyond the base item
* Can be additive, multiplicative, or override
* Example: `+5 Attack` on top of sword's base 10 attack

```
FStatModifier ExtraDamage;
ExtraDamage.StatTag = "Stat.Attack";
ExtraDamage.ModifierType = EStatModifierTypes::Additive;
ExtraDamage.Value = 5.0f;
```

**Crafter Name**

* Displays who crafted the item
* "Crafted by Thorin"
* Used for provenance-based stacking

**Infusions**

* Applied mods/enchantments
* Fire damage, frost effect, etc.
* Each has a power level

```
FItemModSlot FireMod;
FireMod.SlotTag = "Mod.Element.Fire";
FireMod.ModID = "BurningBrand";
FireMod.ModPower = 1.5f;
FireMod.DisplayName = FText::FromString("Flame Brand");
```

**Durability**

* Current durability value (0.0 to MaxDurability)
* Used for equipment wear and tear
* Affects item stacking with durability-based policies

**Creation Time**

* When this item was created
* Used for decay system
* Freshness for food items

**Unique ID**

* Globally unique identifier (GUID)
* Used for save/load
* Tracks specific item instances across sessions

**Owner ID**

* Tracks who owns this item
* Used for loot rights
* Prevents item theft in multiplayer

### **Common Operations**

**Check if Empty**

```
if (ItemInstance.IsEmpty())
{
    // No item in this slot
}
```

**Check Stacking Compatibility**

```
if (ItemInstance.IsStackableWith(OtherInstance))
{
    // Can merge these stacks
}
```

**Get Max Durability**

```
float MaxDurability = ItemInstance.GetMaxDurability();
```

**Serialization**

```
// Save
FItemRecord Record = ItemInstance.ToRecord();

// Load
FItemInstance LoadedInstance = FItemInstance::FromRecord(Record);
```

### **When Are Item Instances Created?**

1. **Picking up items**: WorldItemActor creates instance
2. **Loot drops**: LootComponent generates instances
3. **Crafting**: CraftingComponent creates new instance
4. **Quest rewards**: Manually created in code/Blueprint
5. **Admin commands**: Debug/testing tools