Custom Block Models and Geometry

Custom block models use the standard Bedrock geometry format (format version 1.12.0 or newer) and live inside the RP/models/blocks/ or RP/models/entity/ folder. Even though blocks are static, the game reads their meshes using the same parser as entities. You will typically create these models in Blockbench using the Bedrock Block or Bedrock Entity project type.

The coordinate space is measured in pixels, where 16 units equal one full block. Crucially, the origin (0, 0, 0) of a block geometry is at the bottom-center of the block space, not the bottom-north-west corner. This means a standard full cube spans from -8 to +8 on the X and Z axes, and from 0 to 16 on the Y axis.

Every geometry file requires a unique identifier starting with geometry. followed by your pack's namespace or custom name. You will reference this exact string inside your Behavior Pack block definition.

{
  "format_version": "1.12.0",
  "minecraft:geometry": [
    {
      "description": {
        "identifier": "geometry.wiki.pedestal",
        "texture_width": 64,
        "texture_height": 64,
        "visible_bounds_width": 2,
        "visible_bounds_height": 2,
        "visible_bounds_offset": [0, 0.5, 0]
      },
      "bones": [
        {
          "name": "base",
          "pivot": [0, 0, 0],
          "cubes": [
            {"origin": [-6, 0, -6], "size": [12, 2, 12], "uv": [0, 0]},
            {"origin": [-4, 2, -4], "size": [8, 12, 8], "uv": [0, 14]}
          ]
        },
        {
          "name": "top_plate",
          "pivot": [0, 14, 0],
          "cubes": [
            {"origin": [-7, 14, -7], "size": [14, 2, 14], "uv": [0, 34]}
          ]
        }
      ]
    }
  ]
}

Unlike entity models, which are wired up entirely inside the Resource Pack, custom block models are assigned inside the Behavior Pack block JSON using the minecraft:geometry component. Whenever you use custom geometry, you must also include the minecraft:material_instances component in the same file, or the game will not know which texture or render method to apply to your mesh.

If you simply want a standard full block without making a custom model file, you can use the built-in identifier minecraft:geometry.full_block. This is especially useful when you want the advanced shading or texture control of material_instances without needing an external .geo.json file.

Remember that blocks.json in the Resource Pack should generally be omitted for modern custom blocks that use these components, as defining an entry in blocks.json can override or conflict with the Behavior Pack's geometry component.

{
  "format_version": "1.20.80",
  "minecraft:block": {
    "description": {
      "identifier": "wiki:pedestal"
    },
    "components": {
      "minecraft:geometry": {
        "identifier": "geometry.wiki.pedestal"
      },
      "minecraft:material_instances": {
        "*": {
          "texture": "wiki_pedestal",
          "render_method": "alpha_test"
        }
      },
      "minecraft:collision_box": {
        "origin": [-7, 0, -7],
        "size": [14, 16, 14]
      },
      "minecraft:selection_box": {
        "origin": [-7, 0, -7],
        "size": [14, 16, 14]
      }
    }
  }
}

Creating a separate geometry file for every possible state of a complex block (like pipes, fences, or multi-stage crops) quickly bloats your Resource Pack. Instead, you can build one model containing all possible parts separated into named bones, and toggle them on or off inside the minecraft:geometry component using the bone_visibility object.

Each key inside bone_visibility must match a bone name in your .geo.json file. The value can be a simple boolean (true or false) or a Molang expression string that evaluates block states using the q.block_state() query. This allows a single geometry file to adapt dynamically when permutations update.

{
  "format_version": "1.20.80",
  "minecraft:block": {
    "description": {
      "identifier": "wiki:dynamic_pedestal",
      "states": {
        "wiki:has_plate": [true, false]
      }
    },
    "components": {
      "minecraft:geometry": {
        "identifier": "geometry.wiki.pedestal",
        "bone_visibility": {
          "base": true,
          "top_plate": "q.block_state('wiki:has_plate')"
        }
      },
      "minecraft:material_instances": {
        "*": {
          "texture": "wiki_pedestal",
          "render_method": "alpha_test"
        }
      }
    }
  }
}

The Bedrock rendering engine enforces strict rules on block geometry to keep chunk meshing fast. Visually, a block model is restricted to a 30x30x30 pixel area centered on the block, and at least one pixel of your geometry must overlap the base 16x16x16 block boundary. Meanwhile, your collision_box and selection_box components cannot exceed the standard 16x16x16 space (from -8 to 8 on X/Z, and 0 to 16 on Y).

When you apply a custom model, Minecraft assumes the block is no longer a solid cube and stops culling the faces of adjacent blocks (so you do not get X-ray holes into the ground beneath a custom chair). However, if part of your model sits flush against the edge of the 16x16x16 boundary, or if it extends outside the 16x16x16 space, you may see dark shadows on those faces. In your material_instances, setting ambient_occlusion to false and face_dimming to false often clears up dark shading artifacts on complex or oversized meshes.

Transparency is controlled entirely by the render_method inside minecraft:material_instances, not by the model itself. Even if your geometry is smaller than a full block, leaving render_method on opaque will render unused UV space as solid black or white; switch to alpha_test for cutout textures or blend for stained-glass style translucency.

Rather than exporting four rotated copies of a model for North, South, East, and West orientations, you should combine a single model with the minecraft:transformation component inside your block permutations. The transformation component lets you rotate the entire model in 90-degree increments around the block's center, as well as translate (shift) or scale the mesh.

When you apply a rotation via minecraft:transformation, the game automatically rotates your collision_box and selection_box to match, saving you from recalculating hitbox coordinates for every direction.

Stable in format_version 1.19.40 and above. Thebone_visibility object with Molang support requires format_version 1.19.80 or newer. No experimental toggles are required.

Read out of the game itself, so the ids match the version you are building for.