Simple Structure

Simple Structure Example: Cart

This walkthrough demonstrates creating a simple, single-piece structure using the Cart structure from MoogsVoyagerStructures as an example.

Overview

The Cart structure is a simple decorative structure that:

• Spawns on the surface
• Uses a single NBT file (no jigsaw connections)
• Has minimal configuration
• Perfect for learning the basics

File Structure

data/mvs/
├── structure/
│   └── carts/
│       └── cart.nbt
└── worldgen/
    ├── structure/
    │   └── cart.json
    ├── structure_set/
    │   └── cart.json
    └── template_pool/
        └── carts/
            └── cart/
                └── start_pool.json

Step 1: Create the NBT File

1. Build your cart structure in Minecraft using structure blocks
2. Save it as cart.nbt
3. Place it at: data/mvs/structure/carts/cart.nbt

Note: The structure should be a simple, single-piece design without jigsaw blocks.

Step 2: Create the Template Pool

File: data/mvs/worldgen/template_pool/carts/cart/start_pool.json

{
  "name": "mvs:cart/start_pool",
  "fallback": "minecraft:empty",
  "elements": [
    {
      "weight": 1,
      "element": {
        "location": "mvs:carts/cart",
        "processors": "minecraft:empty",
        "projection": "rigid",
        "element_type": "minecraft:single_pool_element"
      }
    }
  ]
}

Explanation

• name: "mvs:cart/start_pool" - Unique identifier for this pool
• fallback: "minecraft:empty" - Use nothing if pool fails
• elements: Array with one element
  • weight: 1: Only one option, so weight doesn't matter
  • location: "mvs:carts/cart" - References data/mvs/structure/carts/cart.nbt
  • processors: "minecraft:empty" - No block processing
  • projection: "rigid" - Structure stays as-built
  • element_type: "minecraft:single_pool_element" - Standard single piece

Step 3: Create the Structure JSON

File: data/mvs/worldgen/structure/cart.json

{
  "type": "moogs_structures:moogs_structures_generic_jigsaw_structure",
  "start_pool": "mvs:carts/cart/start_pool",
  "size": 1,
  "biomes": "#mvs:has_structure/overworld_biomes",
  "project_start_to_heightmap": "WORLD_SURFACE_WG",
  "cannot_spawn_in_liquid": true,
  "step": "surface_structures",
  "terrain_adaptation": "beard_thin",
  "start_height": {
    "absolute": 0
  },
  "spawn_overrides": {}
}

Field-by-Field Explanation

• type: "moogs_structures:moogs_structures_generic_jigsaw_structure" - Uses generic jigsaw structure type
• start_pool: "mvs:carts/cart/start_pool" - References the template pool we created
• size: 1 - Simple structure, no jigsaw expansion needed
• biomes: "#mvs:has_structure/overworld_biomes" - Spawns in overworld biomes (using a tag)
• project_start_to_heightmap: "WORLD_SURFACE_WG" - Places on world surface
• cannot_spawn_in_liquid: true - Won't spawn in water
• step: "surface_structures" - Generates during surface structures phase
• terrain_adaptation: "beard_thin" - Slight terrain blending
• start_height: { "absolute": 0 } - Starting height (adjusted by heightmap)
• spawn_overrides: {} - No custom entity spawning

Step 4: Create the Structure Set

File: data/mvs/worldgen/structure_set/cart.json

{
  "structures": [
    {
      "structure": "mvs:cart",
      "weight": 1
    }
  ],
  "placement": {
    "type": "moogs_structures:advanced_random_spread",
    "salt": 203698201,
    "spacing": 34,
    "separation": 26
  }
}

Field-by-Field Explanation

• structures: Array with one structure entry
  • structure: "mvs:cart" - References data/mvs/worldgen/structure/cart.json
  • weight: 1 - Only one structure, so weight doesn't matter
• placement: Placement configuration
  • type: "moogs_structures:advanced_random_spread" - Uses advanced random spread
  • salt: 203698201 - Unique identifier (use random large number)
  • spacing: 34 - Average 34 chunks (~544 blocks) between attempts
  • separation: 26 - Minimum 26 chunks (~416 blocks) between structures

Important: spacing (34) must be greater than separation (26)!

How It All Works Together

1. World Generation checks structure sets to see if a structure should spawn
2. Structure Set (cart.json) determines if this chunk is valid:
   • Checks spacing/separation rules
   • Uses salt to determine chunk selection
3. Structure JSON (cart.json) validates the location:
   • Checks biome matches
   • Verifies not in liquid
   • Projects to world surface
4. Template Pool (start_pool.json) selects the structure piece:
   • Only one element, so always selects cart
5. NBT File (cart.nbt) provides the structure data
6. Structure is placed in the world!

Testing Your Structure

1. Create a new world with your datapack/mod installed
2. Use /locate structure mvs:cart to find cart structures
3. Teleport to found locations: /tp @s <coordinates>
4. Verify structure spawned correctly:
   • On surface
   • Not in water
   • In correct biomes
   • Proper spacing from other carts

Common Issues and Solutions

Structure Not Spawning

Check:

• File paths match exactly (case-sensitive)
• JSON syntax is valid
• Biome tags exist
• spacing > separation

Structure Spawning in Wrong Places

Check:

• Biome tags are correct
• cannot_spawn_in_liquid is working
• Terrain is suitable

Structure Not Found with /locate

Check:

• Structure set JSON exists
• Structure JSON exists
• Datapack/mod is loaded
• World was generated after adding structure

Variations

Multiple Variants

To have multiple cart variants, modify the template pool:

{
  "elements": [
    {
      "weight": 2,
      "element": {
        "location": "mvs:carts/cart",
        ...
      }
    },
    {
      "weight": 1,
      "element": {
        "location": "mvs:carts/cart_golden",
        ...
      }
    }
  ]
}

Golden carts spawn half as often as regular carts.

Different Spacing

To make carts more/less common:

{
  "placement": {
    "spacing": 20,    // More common (was 34)
    "separation": 15   // Closer together (was 26)
  }
}

Next Steps

Now that you understand simple structures:

1. Jigsaw Structure Example - Learn about connecting multiple pieces
2. Nether Structure Example - Create Nether-specific structures
3. Complex Structure Example - Build large, expanding structures

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See Also:

• Getting Started - Basics overview
• Structure Files - Complete structure reference
• Template Pools - Pool system details