{
 "id": "40-box-sphere-torus",
 "name": "Box + sphere - torus",
 "description": "Box (-30,-30,-10)..(30,30,0); sphere r12 at origin joined (dome); torus (R22, r4, axis Z, centre origin) cut (half-round groove ring in the box top).",
 "exercises": [
  "revolve",
  "combine_join",
  "combine_cut",
  "torus",
  "sphere"
 ],
 "units": {
  "length": "mm",
  "angle": "deg",
  "area": "mm2",
  "volume": "mm3"
 },
 "conventions": {
  "world": "right-handed; Z up. XY/XZ/YZ are the origin planes.",
  "sketch_frame": "sketch-local 2D coords; world = plane.origin + x*plane.x_dir + y*plane.y_dir (origin in mm). Profile 'loops' list sketch entity ids.",
  "point_refs": "'<id>.start' / '<id>.end' / '<id>.center' reuse (share) that existing sketch point; 'at' is its position when referenced.",
  "extrude_direction": "positive = along sketch plane normal unless stated",
  "selections": "selected faces/edges carry 'point': a world-space point on the face / the edge's parametric midpoint; pick the nearest face/edge to it."
 },
 "parameters": [],
 "features": [
  {
   "op": "sketch",
   "name": "Box_sketch",
   "plane": {
    "ref": "XY",
    "origin": [
     0.0,
     0.0,
     0.0
    ],
    "x_dir": [
     1.0,
     0.0,
     0.0
    ],
    "y_dir": [
     0.0,
     1.0,
     0.0
    ],
    "normal": [
     0.0,
     0.0,
     1.0
    ]
   },
   "entities": [
    {
     "type": "line",
     "start": {
      "at": [
       -30,
       -30
      ]
     },
     "end": {
      "at": [
       30,
       -30
      ]
     },
     "id": "l1"
    },
    {
     "type": "line",
     "start": {
      "ref": "l1.end",
      "at": [
       30.0,
       -30.0
      ]
     },
     "end": {
      "at": [
       30,
       30
      ]
     },
     "id": "l2"
    },
    {
     "type": "line",
     "start": {
      "ref": "l2.end",
      "at": [
       30.0,
       30.0
      ]
     },
     "end": {
      "at": [
       -30,
       30
      ]
     },
     "id": "l3"
    },
    {
     "type": "line",
     "start": {
      "ref": "l3.end",
      "at": [
       -30.0,
       30.0
      ]
     },
     "end": {
      "ref": "l1.start",
      "at": [
       -30.0,
       -30.0
      ]
     },
     "id": "l4"
    }
   ],
   "constraints": [],
   "dimensions": []
  },
  {
   "op": "extrude",
   "name": "Box",
   "operation": "new",
   "profiles": [
    {
     "sketch": "Box_sketch",
     "loops": [
      {
       "outer": true,
       "curves": [
        "l1",
        "l2",
        "l3",
        "l4"
       ]
      }
     ]
    }
   ],
   "extent": {
    "type": "distance",
    "distance": 10,
    "direction": "negative"
   },
   "result_bodies": [
    "A"
   ]
  },
  {
   "op": "sketch",
   "name": "Sphere_sketch",
   "plane": {
    "ref": "XZ",
    "origin": [
     0.0,
     0.0,
     0.0
    ],
    "x_dir": [
     1.0,
     0.0,
     0.0
    ],
    "y_dir": [
     0.0,
     0.0,
     -1.0
    ],
    "normal": [
     0.0,
     1.0,
     0.0
    ]
   },
   "entities": [
    {
     "type": "arc_three_point",
     "start": {
      "at": [
       0.0,
       12.0
      ]
     },
     "mid": [
      12.0,
      0.0
     ],
     "end": {
      "at": [
       0.0,
       -12.0
      ]
     },
     "id": "a1"
    },
    {
     "type": "line",
     "start": {
      "ref": "a1.end",
      "at": [
       0.0,
       -12.0
      ]
     },
     "end": {
      "ref": "a1.start",
      "at": [
       0.0,
       12.0
      ]
     },
     "id": "l1"
    }
   ],
   "constraints": [],
   "dimensions": []
  },
  {
   "op": "revolve",
   "name": "Sphere",
   "operation": "new",
   "profile": {
    "sketch": "Sphere_sketch",
    "loops": [
     {
      "outer": true,
      "curves": [
       "a1",
       "l1"
      ]
     }
    ]
   },
   "axis": {
    "ref": "world Z axis",
    "origin": [
     0,
     0,
     0
    ],
    "dir": [
     0,
     0,
     1
    ]
   },
   "angle": 360,
   "result_bodies": [
    "S"
   ]
  },
  {
   "op": "combine",
   "name": "JoinSphere",
   "operation": "join",
   "target_body": "A",
   "tool_bodies": [
    "S"
   ],
   "keep_tools": false
  },
  {
   "op": "sketch",
   "name": "TorusSketch",
   "plane": {
    "ref": "XZ",
    "origin": [
     0.0,
     0.0,
     0.0
    ],
    "x_dir": [
     1.0,
     0.0,
     0.0
    ],
    "y_dir": [
     0.0,
     0.0,
     -1.0
    ],
    "normal": [
     0.0,
     1.0,
     0.0
    ]
   },
   "entities": [
    {
     "type": "circle",
     "center": {
      "at": [
       22.0,
       0.0
      ]
     },
     "radius": 4,
     "id": "c1"
    }
   ],
   "constraints": [],
   "dimensions": []
  },
  {
   "op": "revolve",
   "name": "Torus",
   "operation": "new",
   "profile": {
    "sketch": "TorusSketch",
    "loops": [
     {
      "outer": true,
      "curves": [
       "c1"
      ]
     }
    ]
   },
   "axis": {
    "ref": "world Z axis",
    "origin": [
     0,
     0,
     0
    ],
    "dir": [
     0,
     0,
     1
    ]
   },
   "angle": 360,
   "result_bodies": [
    "T"
   ]
  },
  {
   "op": "combine",
   "name": "CutTorus",
   "operation": "cut",
   "target_body": "A",
   "tool_bodies": [
    "T"
   ],
   "keep_tools": false
  }
 ]
}