{
 "id": "67-sm-base-flange",
 "name": "Sheet metal: base flange",
 "description": "100x60 rectangle -> base flange (Steel (mm) rule, 2.5 mm).",
 "exercises": [
  "sheet_metal",
  "base_flange",
  "flat_pattern",
  "dxf"
 ],
 "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": "Base",
   "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": [
       100,
       0
      ]
     },
     "id": "l1"
    },
    {
     "type": "line",
     "start": {
      "ref": "l1.end",
      "at": [
       100.0,
       0.0
      ]
     },
     "end": {
      "at": [
       100,
       60
      ]
     },
     "id": "l2"
    },
    {
     "type": "line",
     "start": {
      "ref": "l2.end",
      "at": [
       100.0,
       60.0
      ]
     },
     "end": {
      "at": [
       0,
       60
      ]
     },
     "id": "l3"
    },
    {
     "type": "line",
     "start": {
      "ref": "l3.end",
      "at": [
       0.0,
       60.0
      ]
     },
     "end": {
      "ref": "l1.start",
      "at": [
       0.0,
       0.0
      ]
     },
     "id": "l4"
    }
   ],
   "constraints": [],
   "dimensions": []
  },
  {
   "op": "sm_flange",
   "type": "base",
   "name": "BaseFlange",
   "profile": {
    "sketch": "Base",
    "loops": [
     {
      "outer": true,
      "curves": [
       "l1",
       "l2",
       "l3",
       "l4"
      ]
     }
    ]
   },
   "orientation": "Side 1 (default): thickness grows along the sketch normal (+Z)",
   "operation": "new body",
   "rule": "Steel (mm)"
  }
 ]
}