Generating Custom Jigsaw Structures

Jigsaw structures are the main system of generating custom structures that is used by Mojang to create structures such as Bastions and Villages.

This tutorial will show you how to make a simple dungeon.

Structure Pieces ​

First things first, you will want to make your structure pieces. These can be tunnels or rooms or spawners. I'll make 2 tunnels, a straight piece and a corner. I'll also make a room and a zombie and skeleton spawener to spawn in them. Then go through the tunnels and at each end place a jigsaw block with a target pool named wiki:tunnels, a target name named wiki:tunnel and a name named wiki:tunnel Copy the jigsaw block using ctrl+pick block on computers to copy it's nbt data and place those jigsaw blocks at every entrance to tunnel or room that you want to be counted as a tunnel and spawn tunnel pieces out of it. If you want a piece to only be connected to by tunnel pieces then you can remove target pool and target name and leave the name field or if you want the opposite you can remove the name field and the entrance will only generate tunnels.

The jigsaw settings for the tunnel pieces and the room piece.

I'll do the above steps with my tunnels and room entrances. For spawners I'll place a jigsaw facing upwards in the middle of the room with a target name specifying wiki:spawner and a target pool specifying wiki:spawners. Then on the zombie and skeleton spawners I'll place a block beneath them with the name field specifying wiki:spawner then I'll set the turns into field to minecraft:stone_bricks.

The jigsaw settings for the jigsaw block placing spawners.

After that is done you can save the structure pieces and we move into the programming portion of the structure.

All the completed structure templates.

Template Pools ​

If you don't already have a worldgen folder then create a folder named worldgen at the base level of the behavior pack on the same level as the manifest file. Then inside that folder make a new folder called template_pools. Inside that folder create a file called tunnels.json in that file put the following contents:

Template pool format ​

In the location field place the write the file path to your tunnel structure files respective to their level within the structures folder of the behavior pack.

{
    "format_version": "1.21.100",
    "minecraft:template_pool": {
        "description": {
            "identifier": "wiki:tunnels"
        },
        "elements": [
            {
                "element": {
                    "element_type": "minecraft:single_pool_element",
                    "location": "wiki/example_dungeon/tunnels/tunnel_01"
                }
            },
            {
                "element": {
                    "element_type": "minecraft:single_pool_element",
                    "location": "wiki/example_dungeon/tunnels/tunnel_02"
                }
            },
            {
                "element": {
                    "element_type": "minecraft:single_pool_element",
                    "location": "wiki/example_dungeon/tunnels/room_01"
                }
            }
        ]
    }
}

Next up create the spawners template pool file

{
    "format_version": "1.21.100",
    "minecraft:template_pool": {
        "description": {
            "identifier": "wiki:spawners"
        },
        "elements": [
            {
                "element_type": "minecraft:single_pool_element",
                "location": "wiki/example_dungeon/spawners/spawner_01"
            },
            {
                "element_type": "minecraft:single_pool_element",
                "location": "wiki/example_dungeon/spawners/spawner_02"
            }
        ]
    }
}

Now you are done with the template pools!

Configuration Format ​

The configuration file governs how the structure is to be generated. It tells the game how large it should be, what pieces should be used to start its generation, the biomes it can spawn in, and the way water works with it. They are stored in the structures subfolder of the worldgen folder.

Configuration format ​

These settings will make the structure always spawn at y level 0 and in any biome in the overworld.

{
    "format_version": "1.21.130",
    "minecraft:jigsaw": {
        "description": {
            "identifier": "wiki:dungeon"
        },
        "step": "underground_structures",
        "liquid_settings": "ignore_waterlogging",
        "start_height": {
            "type": "constant",
            "value": {
                "absolute": 0
            }
        },
        "max_depth": 15,
        "terrain_adaptation": "bury",
        "start_pool": "wiki:tunnels",
        "biome_filters": [
            {
                "test": "has_biome_tag",
                "value": "overworld"
            }
        ],
        "max_distance_from_center": 128,
        "dimension_padding": 10
    }
}

Now that you are done with the configuration file and template pools you have only one step left, structure sets!

Structure Set ​

A structure set tells the game where to place a structure and how far apart one another should be from each other. They are stored in the structure_sets folder of the worldgen folder

Structure Set format ​

This structure set will place a giant grid of 50 chunk by 50 chunk squares where the structure can spawn in the world seperated by 10 chunk boundries between the grid squares. The salt and spread_types are used to randomize the placement of the structures in the set within a grid square.

{
    "format_version": "1.21.130",
    "minecraft:structure_set": {
        "description": {
            "identifier": "wiki:dungeon_set"
        },
        "placement": {
            "type": "minecraft:random_spread",
            "salt": 39815673,
            "separation": 10,
            "spacing": 50,
            "spread_type": "linear"
        },
        "structures": [
            {
                "structure": "wiki:dungeon",
                "weight": 1
            }
        ]
    }
}

And thats it! Your structure should now be generating in the world.

Next you can check out the Jigsaw Structures to learn more about more complicated jigsaw features.