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Overview

Fabrication recipes define advanced item synthesis performed inside the Matter Fabricator. Unlike vanilla crafting, fabrication is order-independent: the machine checks that every required ingredient is present in its input slots without regard to position. Up to 3 ingredients are supported per recipe.

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Recipe Type ID

gm:fabrication

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JSON Format

Fabrication recipes are stored under data/<namespace>/recipe/ in a datapack. The file must declare the gm:fabrication type. 
{
  "type": "gm:fabrication",
  "ingredients": [
    { "item": "minecraft:iron_ingot" },
    { "item": "minecraft:redstone" },
    { "tag": "c:dusts/copper" }
  ],
  "result": {
    "id": "gm:advanced_circuit",
    "count": 1
  }
}

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Fields

FieldTypeRequiredDescription
typestringyesMust be gm:fabrication.
ingredientsarrayyesList of 1–3 ingredient objects. Each entry follows the standard Minecraft ingredient format (item, tag, or components).
resultobjectyesThe output ItemStack. Uses the standard ItemStack codec: id (required) and count (optional, defaults to 1).

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Ingredient format

Each object in ingredients is a standard Minecraft Ingredient. Common forms: 
{ "item": "minecraft:gold_ingot" }

{ "tag": "c:ingots/gold" }

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Result format

The result field uses the standard NeoForge ItemStack codec: 
{
  "id": "gm:processor_chip",
  "count": 2
}

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Adding Custom Fabrication Recipes via Datapack

  1. Create a datapack with the following layout: 
    my_datapack/
└── data/
    └── my_mod/
        └── recipe/
            └── my_fabrication_recipe.json
  2. Write the recipe JSON following the format above.
  3. Place the datapack in the datapacks/ folder of your world, or package it inside a mod’s resources/data/ directory.

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Example: single-ingredient recipe

{
  "type": "gm:fabrication",
  "ingredients": [
    { "tag": "c:ingots/tin" }
  ],
  "result": {
    "id": "gm:tin_dust",
    "count": 1
  }
}

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Example: multi-ingredient recipe

{
  "type": "gm:fabrication",
  "ingredients": [
    { "item": "minecraft:diamond" },
    { "item": "minecraft:obsidian" },
    { "tag": "c:dusts/redstone" }
  ],
  "result": {
    "id": "gm:quantum_core",
    "count": 1
  }
}

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JEI Integration

Fabrication recipes are visible in JEI under the Matter Fabricator category. You can:
  • Press R on any item to see if it is produced by a fabrication recipe.
  • Press U on any ingredient to see which fabrication recipes consume it.
  • Click the Matter Fabricator icon in the JEI category list to browse all fabrication recipes.

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