1. Purpose

The save system preserves the full runtime state of a BP_DiggableArea, including:

• Terrain deformation
• Visual dig mask
• Spawned/expoxed underground items
• Volume identity

After loading, the volume must visualli and logically match the saved data.

2. Data Structure

All area data is stored inside FDiggableVolumeSaveData

2.1 Stored Fields

Volume identity

• volumeID (String )→ Unique identifier to match saved data with the correct BP_DiggableArea instance**.**

Terrain State

• savedDensityField (TArray<float>) → Stores voxel density values (solid vs air).
• savedDigMask (TArray<float>) → Stores dig mask values used for visual feedback and surface coloring.
• savedUndergroundItemIds (TArray<int32>) → Stores the item type assigned to each voxel cell.

Exposed Items

• exposedItems (TArray<FSpawnedItemSave>)
  • itemTypeId → Index into undergroundItems
  • location → World position
  • rotation → Actor rotation
  • scale → Actor scale
  • currentHits → Remaining durability

3. Methods / Blueprints

This plugin exposes two Blueprint-callable methods intended to be the main public API for saving and loading a BP_DiggableArea.