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finnsetchell edited this page Dec 12, 2025 · 3 revisions

Complex Structure Example: Cathedral

This walkthrough demonstrates creating a large, complex jigsaw structure using the Cathedral structure from MoogsVoyagerStructures as an example. Complex structures use multiple pools, jigsaw expansion, and advanced features.

Overview

The Cathedral structure demonstrates:

  • Large jigsaw expansion (size: 17)
  • Maximum distance limits (max_distance_from_center: 35)
  • Multiple template pools
  • Spawn overrides for custom entities
  • Rare structure placement

File Structure

data/mvs/
├── structure/
│   └── cathedral/
│       ├── base/
│       │   ├── base.nbt
│       │   └── bottom.nbt
│       ├── corridors/
│       │   └── (multiple .nbt files)
│       ├── special/
│       │   └── (multiple .nbt files)
│       └── ...
└── worldgen/
    ├── structure/
    │   └── cathedral.json
    ├── structure_set/
    │   └── cathedral.json
    └── template_pool/
        └── cathedral/
            └── temp.json

Step 1: Create Multiple NBT Files

Complex structures require many pieces:

Main Pieces

  • cathedral/base/base.nbt - Main base piece
  • cathedral/base/bottom.nbt - Bottom section
  • cathedral/cathedral_start.nbt - Starting piece

Corridors

  • cathedral/corridors/corridor_1.nbt through corridor_8.nbt
  • Various corridor configurations

Special Rooms

  • cathedral/special/room_1.nbt through room_13.nbt
  • Special rooms and features

Jigsaw Connections

Each piece contains jigsaw blocks that connect to other pieces:

  • Base connects to corridors
  • Corridors connect to special rooms
  • Corridors connect to other corridors
  • Special rooms connect back to corridors

Jigsaw Block Setup:

  • Name: Pool to connect to (e.g., mvs:cathedral/corridor)
  • Target: Jigsaw block name in target pieces (e.g., cathedral_corridor)

Step 2: Create Multiple Template Pools

Start Pool

File: data/mvs/worldgen/template_pool/cathedral/temp.json

{
  "name": "temp",
  "fallback": "minecraft:empty",
  "elements": [
    {
      "weight": 1,
      "element": {
        "element_type": "minecraft:single_pool_element",
        "projection": "rigid",
        "location": "mvs:cathedral/base/base",
        "processors": "minecraft:empty"
      }
    }
  ]
}

Corridor Pool

File: data/mvs/worldgen/template_pool/cathedral/corridor.json

{
  "name": "mvs:cathedral/corridor",
  "fallback": "minecraft:empty",
  "elements": [
    {
      "weight": 1,
      "element": {
        "location": "mvs:cathedral/corridors/corridor_1",
        "processors": "minecraft:empty",
        "projection": "rigid",
        "element_type": "minecraft:single_pool_element"
      }
    },
    {
      "weight": 1,
      "element": {
        "location": "mvs:cathedral/corridors/corridor_2",
        "processors": "minecraft:empty",
        "projection": "rigid",
        "element_type": "minecraft:single_pool_element"
      }
    }
    // ... more corridor variants
  ]
}

Special Room Pool

File: data/mvs/worldgen/template_pool/cathedral/special.json

{
  "name": "mvs:cathedral/special",
  "fallback": "minecraft:empty",
  "elements": [
    {
      "weight": 1,
      "element": {
        "location": "mvs:cathedral/special/room_1",
        "processors": "minecraft:empty",
        "projection": "rigid",
        "element_type": "minecraft:single_pool_element"
      }
    }
    // ... more special room variants
  ]
}

Step 3: Create the Structure JSON

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

{
  "type": "moogs_structures:moogs_structures_generic_jigsaw_structure",
  "start_pool": "mvs:cathedral/temp",
  "size": 17,
  "max_distance_from_center": 35,
  "project_start_to_heightmap": "WORLD_SURFACE_WG",
  "cannot_spawn_in_liquid": true,
  "terrain_height_radius_check": 1,
  "allowed_terrain_height_range": 5,
  "liquid_settings": "ignore_waterlogging",
  "biomes": "#mvs:has_structure/overworld_biomes",
  "step": "surface_structures",
  "terrain_adaptation": "beard_thin",
  "start_height": {
    "absolute": 0
  },
  "spawn_overrides": {
    "monster": {
      "bounding_box": "full",
      "spawns": [
        {
          "type": "minecraft:skeleton",
          "weight": 1,
          "minCount": 1,
          "maxCount": 2
        },
        {
          "type": "minecraft:zombie",
          "weight": 2,
          "minCount": 2,
          "maxCount": 5
        }
      ]
    }
  }
}

Key Features Explained

Large Size

{
  "size": 17
}

What this does:

  • Allows structure to expand up to 17 jigsaw connections
  • Creates large, complex structures
  • Higher values = larger structures (max 30)

Maximum Distance Limit

{
  "max_distance_from_center": 35
}

What this does:

  • Limits how far pieces can extend from center
  • Prevents structures from growing too large
  • 35 blocks = pieces must be within 35 blocks of center

Why: Controls total structure size even with high size value.

Terrain Height Range

{
  "terrain_height_radius_check": 1,
  "allowed_terrain_height_range": 5
}

What this does:

  • Checks terrain in 1 chunk radius
  • Allows up to 5 block height difference
  • More lenient than simple structures (cathedrals are large)

Liquid Settings

{
  "liquid_settings": "ignore_waterlogging"
}

What this does:

  • Handles waterlogging in structure blocks
  • Important for large structures near water

Spawn Overrides

{
  "spawn_overrides": {
    "monster": {
      "bounding_box": "full",
      "spawns": [
        {
          "type": "minecraft:skeleton",
          "weight": 1,
          "minCount": 1,
          "maxCount": 2
        },
        {
          "type": "minecraft:zombie",
          "weight": 2,
          "minCount": 2,
          "maxCount": 5
        }
      ]
    }
  }
}

What this does:

  • Spawns custom entities in the structure
  • monster category spawns hostile mobs
  • bounding_box: "full" spawns throughout entire structure
  • Weighted random selection:
    • Skeletons: 1/3 chance, 1-2 spawn
    • Zombies: 2/3 chance, 2-5 spawn

Step 4: Create the Structure Set

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

{
  "structures": [
    {
      "structure": "mvs:cathedral",
      "weight": 1
    }
  ],
  "placement": {
    "type": "moogs_structures:advanced_random_spread",
    "salt": 303685798,
    "spacing": 105,
    "separation": 98,
    "min_distance_from_world_origin": 1000
  }
}

Rare Structure Placement

Spacing: 105 chunks (~1680 blocks)

  • Very rare structure
  • High spacing = uncommon spawns

Separation: 98 chunks (~1568 blocks)

  • High separation = far apart
  • Prevents multiple cathedrals nearby

Minimum Distance: 1000 blocks

  • Only spawns far from world spawn
  • Creates exploration goal
  • End-game content

How Complex Expansion Works

Expansion Flow

1. Start Pool places base piece
   ↓
2. Base jigsaw blocks reference corridor pool
   ↓
3. Corridor pool selects random corridor piece
   ↓
4. Corridor connects to base
   ↓
5. Corridor jigsaw blocks reference:
   - More corridors (continues expansion)
   - Special rooms (branches off)
   ↓
6. Process repeats until:
   - size limit (17) reached
   - max_distance_from_center (35) reached
   - No more jigsaw connections available

Jigsaw Connection Example

Base Piece (base.nbt):

  • Contains jigsaw blocks:
    • Name: mvs:cathedral/corridor
    • Target: cathedral_corridor

Corridor Piece (corridor_1.nbt):

  • Contains jigsaw blocks:
    • Name: mvs:cathedral/corridor (continues corridor)
    • Target: cathedral_corridor
    • Name: mvs:cathedral/special (branches to rooms)
    • Target: cathedral_special

Special Room (room_1.nbt):

  • Contains jigsaw blocks:
    • Name: mvs:cathedral/corridor (returns to corridor)
    • Target: cathedral_corridor

Testing Your Structure

  1. Create a new world with your datapack/mod
  2. Travel far from spawn (1000+ blocks)
  3. Use /locate structure mvs:cathedral to find cathedrals
  4. Verify:
    • Structure expands correctly
    • Stays within size limits
    • Custom entities spawn
    • Proper spacing from other cathedrals
    • Terrain is suitable

Common Issues

Structure Too Large

Solutions:

  • Reduce size value
  • Lower max_distance_from_center
  • Limit jigsaw connections in NBT files

Structure Not Expanding

Check:

  • Jigsaw blocks are placed correctly
  • Pool names match jigsaw block names
  • Target names match between pieces
  • size is high enough

Entities Not Spawning

Check:

  • Spawn override syntax is correct
  • Entity types are valid
  • bounding_box is set correctly
  • Structure has valid spawn locations

Advanced: Pools That Ignore Boundaries

For decorative elements that can extend beyond limits:

{
  "pools_that_ignore_boundaries": [
    "mvs:cathedral/decorative_pool"
  ]
}

Allows decorative pools to extend beyond max_distance_from_center.

Advanced: Multiple Structure Variants

To have multiple cathedral variants:

Structure Set:

{
  "structures": [
    {
      "structure": "mvs:cathedral",
      "weight": 3
    },
    {
      "structure": "mvs:cathedral_ruined",
      "weight": 1
    }
  ]
}

Ruined cathedrals spawn 1/3 as often as regular cathedrals.

Design Tips for Complex Structures

  1. Plan Your Layout - Sketch structure before building
  2. Modular Pieces - Create reusable corridor/room pieces
  3. Clear Connections - Use consistent jigsaw naming
  4. Test Incrementally - Test each pool separately
  5. Limit Growth - Use max_distance_from_center to control size
  6. Variety - Multiple variants keep structures interesting
  7. Documentation - Note jigsaw connections for reference

Comparison: Simple vs Complex

Feature Simple (Cart) Complex (Cathedral)
Size 1 17
Max Distance Not set 35
Pools 1 Multiple
Jigsaw None Extensive
Spawn Overrides None Custom entities
Spacing 34 chunks 105 chunks
Min Distance None 1000 blocks

Next Steps

Now that you understand complex structures:

  1. Advanced Topics - More advanced features
  2. Structure Files - Complete reference
  3. Template Pools - Advanced pool techniques

See Also:

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