[
  {
    "type": "source_component",
    "source_component_id": "empty",
    "ftype": "printedpart",
    "name": "EMPTY"
  },
  {
    "type": "cad_component",
    "cad_component_id": "cad_empty",
    "source_component_id": "empty",
    "position": { "x": 0, "y": 0, "z": 0 },
    "model_jscad": {
      "type": "subtract",
      "shapes": [
        { "type": "cuboid", "size": [4, 4, 4] },
        { "type": "cuboid", "size": [4, 4, 4] }
      ]
    },
    "model_object_fit": "contain_within_bounds",
    "anchor_alignment": "center"
  }
]