Structures

Structures define the multiblock layout a controller must detect before recipes can run.

A structure belongs in a datapack path such as:

data/<namespace>/mm/structures/<path>.json

The structure ID is the datapack resource location relative to mm/structures. For example:

data/mypack/mm/structures/coke_oven.json

becomes:

mypack:coke_oven

Example

{
  "name": "My Machine",
  "controllerIds": "mm:controller_a",
  "layout": [
    ["  A  "],
    ["1PCD2"],
    ["1P D2"]
  ],
  "key": {
    "A": { "block": "minecraft:glass" },
    "P": { "port": "mm:my_port", "input": true },
    "D": { "portType": "mm:item", "input": false },
    "1": { "port": "mm:my_port", "input": true },
    "2": { "port": "mm:my_port", "input": false }
  }
}

Field	Meaning
`name`	Display name shown for the formed structure.
`controllerIds`	Single controller ID or list of controller IDs that can form this structure.
`layout`	3D character layout, stored as layers of rows. Spaces are ignored.
`key`	Maps each layout character to a block, port, tag, or port-type requirement.

Layout orientation

Each layer is read row-by-row. The top row is treated as the north-most row. In practice, align the controller position consistently, usually on the south/front side of the layer.

"layout": [
  [
    "BBB",
    "ACB"
  ]
]

`portsAnywhere`

At the structure root, portsAnywhere: true allows normal port and port-type pieces to match any candidate port position instead of requiring an exact coordinate. Each required anywhere-port piece still needs a unique matching port.

{
  "portsAnywhere": true,
  "layout": [["III", "ACA", "OOO"]],
  "key": {
    "I": { "portType": "mm:item", "input": true },
    "O": { "portType": "mm:item", "input": false }
  }
}

For exact port matching, use the base port id plus input: true or input: false. For a port registered as my_port, use port: "mm:my_port", not port: "mm:my_port_input". The generated block ids are still mm:my_port_input and mm:my_port_output, but the structure port requirement is intended to use the base port id.

Port-type pieces

A structure can require any port of a given type instead of a specific port ID:

"I": {
  "portType": "mm:item",
  "input": true,
  "minTier": 1,
  "maxTier": 3
}

input is optional. If omitted, either input or output may match. minTier defaults to 1; maxTier defaults to effectively unlimited.

Parallel cap

Structures can define their own parallel recipe cap:

"maxParallelRecipes": 5

-1 or an omitted field means the structure does not override the controller/global value.

See Structure Requirements for available key-entry formats.