{
 "sources": [
  "tangency-labs/solidcraft#12"
 ],
 "what": "Offset Face on one piece of a split face moves only that piece, not the coplanar neighbour",
 "source": "analytic",
 "method": "box 40x30x10, top face split at x=20; the x<20 piece moves up 2 mm: V=12000+20*30*2=13200; faces: bottom, front, back, left, right, two top pieces, step wall at x=20 = 8; bbox z 0..12",
 "body_count": 1,
 "volume_mm3": 13200,
 "faces": 8
}