{
  "version": "0.1",
  "nodes": {
    "1": { "id": 1, "name": "base_cylinder", "op": {"type": "Cylinder", "radius": 20, "height": 10, "segments": 32} },
    "2": { "id": 2, "name": "top_cylinder_prim", "op": {"type": "Cylinder", "radius": 10, "height": 15, "segments": 32} },
    "3": { "id": 3, "name": "top_cylinder", "op": {"type": "Translate", "child": 2, "offset": {"x": 0, "y": 0, "z": 10}} },
    "4": { "id": 4, "name": "stepped_shaft", "op": {"type": "Union", "left": 1, "right": 3} }
  },
  "materials": {},
  "part_materials": {},
  "roots": [{ "root": 4, "material": "default" }]
}