{
  "source": "analytic",
  "method": "belt: convex hull of circles R20 @ (0,0) and r10 @ (50,0) (external tangents, sin a = (R-r)/d) minus the d8 hole at (50,0), extruded 5 as one body; hull area = (R+r) sqrt(d^2-(R-r)^2) + R^2(pi+2a)/2 + r^2(pi-2a)/2; moments by Green's theorem over the line/arc boundary",
  "body_count": 1,
  "volume_mm3": 11326.169514235082,
  "area_mm2": 5637.404150511762,
  "center_of_mass": [
    15.321857347287981,
    0.0,
    2.5
  ],
  "bbox": {
    "min": [
      -20.0,
      -20.0,
      0.0
    ],
    "max": [
      60.0,
      20.0,
      5.0
    ]
  },
  "faces": 7
}