{
 "id": "30-fillet-after-shell",
 "name": "Fillets after shell",
 "description": "60x40x30 box shelled 3 mm (top open); outer vertical edges R6, inner vertical edges R3, then the inner floor loop R1 (tangent chain).",
 "exercises": [
  "shell",
  "fillet",
  "fillet_after_shell",
  "tangent_chain"
 ],
 "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": "Extrude1_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": [
       0,
       0
      ]
     },
     "end": {
      "at": [
       60,
       0
      ]
     },
     "id": "l1"
    },
    {
     "type": "line",
     "start": {
      "ref": "l1.end",
      "at": [
       60.0,
       0.0
      ]
     },
     "end": {
      "at": [
       60,
       40
      ]
     },
     "id": "l2"
    },
    {
     "type": "line",
     "start": {
      "ref": "l2.end",
      "at": [
       60.0,
       40.0
      ]
     },
     "end": {
      "at": [
       0,
       40
      ]
     },
     "id": "l3"
    },
    {
     "type": "line",
     "start": {
      "ref": "l3.end",
      "at": [
       0.0,
       40.0
      ]
     },
     "end": {
      "ref": "l1.start",
      "at": [
       0.0,
       0.0
      ]
     },
     "id": "l4"
    }
   ],
   "constraints": [],
   "dimensions": []
  },
  {
   "op": "extrude",
   "name": "Extrude1",
   "operation": "new",
   "profiles": [
    {
     "sketch": "Extrude1_sketch",
     "loops": [
      {
       "outer": true,
       "curves": [
        "l1",
        "l2",
        "l3",
        "l4"
       ]
      }
     ]
    }
   ],
   "extent": {
    "type": "distance",
    "distance": 30,
    "direction": "positive"
   },
   "result_bodies": [
    "Box"
   ]
  },
  {
   "op": "shell",
   "name": "Shell1",
   "faces_removed": [
    {
     "type": "plane",
     "normal_at_point_on_face": [
      0.0,
      0.0,
      1.0
     ],
     "plane_normal_outward": [
      0.0,
      0.0,
      1.0
     ],
     "point": [
      30.0,
      20.0,
      30.0
     ]
    }
   ],
   "face_selection": "top face (z=30)",
   "inside_thickness": 3,
   "outside_thickness": 0,
   "tangent_chain": false
  },
  {
   "op": "fillet",
   "name": "OuterFillet",
   "type": "constant_radius",
   "radius": 6,
   "tangent_chain": false,
   "edge_selection": "the 4 outer vertical edges (x in {0,60}, y in {0,40})",
   "edges": [
    {
     "type": "line",
     "start": [
      0.0,
      40.0,
      0.0
     ],
     "end": [
      0.0,
      40.0,
      30.0
     ],
     "point": [
      0.0,
      40.0,
      15.0
     ]
    },
    {
     "type": "line",
     "start": [
      60.0,
      40.0,
      0.0
     ],
     "end": [
      60.0,
      40.0,
      30.0
     ],
     "point": [
      60.0,
      40.0,
      15.0
     ]
    },
    {
     "type": "line",
     "start": [
      60.0,
      0.0,
      0.0
     ],
     "end": [
      60.0,
      0.0,
      30.0
     ],
     "point": [
      60.0,
      0.0,
      15.0
     ]
    },
    {
     "type": "line",
     "start": [
      0.0,
      0.0,
      0.0
     ],
     "end": [
      0.0,
      0.0,
      30.0
     ],
     "point": [
      0.0,
      0.0,
      15.0
     ]
    }
   ]
  },
  {
   "op": "fillet",
   "name": "InnerFillet",
   "type": "constant_radius",
   "radius": 3,
   "tangent_chain": false,
   "edge_selection": "the 4 inner vertical edges (x in {3,57}, y in {3,37}, z 3..30)",
   "edges": [
    {
     "type": "line",
     "start": [
      57.0,
      37.0,
      3.0
     ],
     "end": [
      57.0,
      37.0,
      30.0
     ],
     "point": [
      57.0,
      37.0,
      16.5
     ]
    },
    {
     "type": "line",
     "start": [
      3.0,
      37.0,
      3.0
     ],
     "end": [
      3.0,
      37.0,
      30.0
     ],
     "point": [
      3.0,
      37.0,
      16.5
     ]
    },
    {
     "type": "line",
     "start": [
      57.0,
      3.0,
      3.0
     ],
     "end": [
      57.0,
      3.0,
      30.0
     ],
     "point": [
      57.0,
      3.0,
      16.5
     ]
    },
    {
     "type": "line",
     "start": [
      3.0,
      3.0,
      3.0
     ],
     "end": [
      3.0,
      3.0,
      30.0
     ],
     "point": [
      3.0,
      3.0,
      16.5
     ]
    }
   ]
  },
  {
   "op": "fillet",
   "name": "FloorFillet",
   "type": "constant_radius",
   "radius": 1,
   "tangent_chain": true,
   "edge_selection": "one edge of the inner floor (z=3) + tangent chain = whole floor boundary loop",
   "edges": [
    {
     "type": "arc",
     "start": [
      3.0,
      6.0,
      3.0
     ],
     "end": [
      6.0,
      3.0,
      3.0
     ],
     "center": [
      6.0,
      6.0,
      3.0
     ],
     "axis": [
      0.0,
      0.0,
      1.0
     ],
     "point": [
      3.878679656,
      3.878679656,
      3.0
     ]
    }
   ]
  }
 ]
}