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World Item Decay & Spoilage

Note:
The decay system is part of the broader item framework.
This section focuses on how it relates to dropped loot / world items.

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Overview

World-spawned items (loot on the ground) can:
  • Decay over time (durability loss)
  • Despawn after a configured time
  • Optionally be converted to a spoiled variant (e.g., fresh meat → spoiled meat)
This prevents infinite world clutter and supports survival-style spoilage mechanics.

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Configuration

On ItemDataAsset:
  • Can Decay: true/false
  • Decay Rate: 0.1 (example)
    • Interpreted as durability loss per second (or per tick depending on your implementation)
On WorldItemActor:
  • Despawn Time: e.g. 300.0 (seconds)
    • How long an item can exist in the world before auto-despawn
    • 0 or negative can be used to disable timed despawn if desired

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How It Works (Conceptual)

  1. A world item is spawned (loot drop, dropped item, etc.)
  2. Over time:
    • Durability is reduced using the item’s decay rate
    • Or a lifetime countdown runs based on Despawn Time
  3. When:
    • Durability reaches 0 or
    • The item’s lifetime expires
      Then one of the following happens:
    • The item is destroyed
    • Or replaced with a “spoiled” variant (e.g., fresh → spoiled food)

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Spoiled Items (Example Pattern)

For food or other perishable items, you can implement a “spoiled” variant. Example Blueprint logic inside BP_WorldItemActor: 
Event Tick (or Timer every 1 second)
   ↓
Branch: ItemData.CanDecay ?
   True:
      ItemInstance.Durability -= ItemData.DecayRate * DeltaTime
      ↓
      Branch: Durability <= 0 ?
         True:
            // Convert to spoiled version
            Set Item Data = DA_SpoiledMeat   (or your spoiled asset)
            Reset Durability (optional)
            Set Despawn Time = 60 seconds    (optional shorter timer)
         False:
            // Still good, keep updating
   False:
      // No decay, do nothing
Important:
The exact implementation (Tick vs Timer vs central manager) is up to your project.
UMI provides the data hooks (durability, decay rate, world item actor), but you can tailor the behavior to your genre and performance needs.