{
  "systemCount": 40000,
  "radius": 20000,
  "layout": {
    "coreFraction": 0.25,
    "bulgeSigma": 0.09,
    "diskSkew": 1.7,
    "flatten": 0.62,
    "spiral": { "enabled": true, "arms": 2, "twist": 2.6, "strength": 0.5 }
  },
  "distribution": {
    "rules": []
  },
  "startingSystem": { "policy": "center" },
  "settlements": {
    "gradient": { "falloff": 0.7, "floor": 0.22 }
  },
  "neighbors": 8
}