{
  "chassis": {
    "scale": "1/27 Compact",
    "wheelbase_mm": 102,
    "track_front_mm": 58,
    "track_rear_mm": 60,
    "deck_mm": [80, 135, 2.5],
    "deck_material": "PETG",
    "ground_clearance_mm": 7,
    "shocks": "PN Racing Mini-Z oil-filled, ~30mm"
  },
  "drivetrain": [
    {"slot": "Front wheels", "model": "PN Racing PN-WS-F1", "size_mm": "Ø25×8", "qty": 2, "search_query": "PN Racing F1 front wheel 25mm Mini-Z", "price_usd": 8.0, "source": "buy"},
    {"slot": "Rear wheels",  "model": "PN Racing PN-WS-R1", "size_mm": "Ø28×11", "qty": 2, "search_query": "PN Racing R1 rear wheel 28mm Mini-Z", "price_usd": 8.0, "source": "buy"},
    {"slot": "Front bearing","model": "684ZZ (4×9×4)", "qty": 2, "search_query": "684ZZ bearing 4x9x4 10pcs", "price_usd": 1.5, "source": "buy"},
    {"slot": "Rear bearing", "model": "693ZZ (3×8×4)", "qty": 2, "search_query": "693ZZ bearing 3x8x4 10pcs", "price_usd": 1.0, "source": "buy"},
    {"slot": "Dogbones",     "model": "PN Racing PN-DB-30 steel", "qty": 2, "search_query": "PN Racing dogbone drive shaft Mini-Z", "price_usd": 4.0, "source": "buy"},
    {"slot": "Pinion",       "model": "M0.3 10T steel", "qty": 1, "search_query": "M0.3 pinion 10T steel Mini-Z", "price_usd": 1.5, "source": "buy"},
    {"slot": "Spur gear",    "model": "M0.3 56T delrin", "qty": 1, "search_query": "M0.3 spur gear 56T Mini-Z", "price_usd": 1.5, "source": "buy"},
    {"slot": "Motor",        "model": "RC0820 brushless 8500KV", "size_mm": "Ø8×20", "voltage": "2S", "search_query": "RC0820 brushless motor 8500KV", "price_usd": 6.0, "source": "buy"},
    {"slot": "ESC",          "model": "Hobbywing Quicrun WP 1040-BR", "size_mm": "24×16×6", "current": "40A", "waterproof": true, "search_query": "Hobbywing Quicrun WP 1040-BR 2S", "price_usd": 18.0, "source": "buy"},
    {"slot": "Servo",        "model": "PN Racing PN-SRV-001 Mini-Z", "size_mm": "22×11×20", "torque": "1.5kg", "search_query": "PN Racing PN-SRV-001 servo Mini-Z", "price_usd": 9.0, "source": "buy"},
    {"slot": "Battery",      "model": "2S LiPo 300mAh 50C XT30", "size_mm": "35×20×12", "search_query": "2S 300mAh 50C LiPo XT30", "price_usd": 6.0, "source": "buy"},
    {"slot": "Shocks",       "model": "PN Racing PN-SHK-30 oil-filled Mini-Z", "qty": 4, "search_query": "PN Racing Mini-Z oil shock 30mm", "price_usd": 14.0, "source": "buy"},
    {"slot": "M2 screws",    "model": "M2 assorted kit", "qty": 1, "search_query": "M2 screw kit Mini-Z RC", "price_usd": 4.0, "source": "buy"}
  ],
  "fpv": [
    {"slot": "FPV Camera",   "model": "Eachine C01 PRO 1200TVL", "size_mm": "14×14×16", "search_query": "Eachine C01 PRO 1200TVL FPV camera", "price_usd": 12.0, "source": "buy"},
    {"slot": "VTX",          "model": "Eachine TX01S 5.8GHz 25mW", "size_mm": "14×11×3", "search_query": "Eachine TX01S 25mW VTX", "price_usd": 9.0, "source": "buy"},
    {"slot": "VTX antenna",  "model": "Pagoda RHCP 5.8GHz stubby", "search_query": "Pagoda RHCP 5.8GHz stubby antenna", "price_usd": 2.0, "source": "buy"},
    {"slot": "VRX (PC side)","model": "Eachine ProDVR 5.8GHz USB", "search_query": "Eachine ProDVR 5.8GHz USB receiver", "price_usd": 22.0, "source": "buy"},
    {"slot": "VRX antenna",  "model": "RHCP 5.8GHz panel", "search_query": "5.8GHz RHCP panel antenna FPV", "price_usd": 5.0, "source": "buy"}
  ],
  "agent": [
    {"slot": "MCU",          "model": "ESP32-S3-WROOM-1 DevKitC-1", "search_query": "ESP32-S3 DevKitC-1 N8R2", "price_usd": 6.0, "source": "buy"},
    {"slot": "IMU",          "model": "GY-521 MPU-6050", "search_query": "GY-521 MPU-6050 module", "price_usd": 1.5, "source": "buy"},
    {"slot": "Buck 5V",      "model": "Mini-360 DC-DC step-down", "search_query": "Mini-360 DC-DC buck converter 5V", "price_usd": 1.0, "source": "buy"}
  ],
  "printed_parts": [
    {"slot": "Chassis deck (нижняя плита)", "material": "PETG", "qty": 1, "stl": "chassis_deck.stl", "print_time_min": 35, "weight_g": 22, "notes": "основная дека, 2.5мм"},
    {"slot": "Electronics plate (верхняя плита)", "material": "PETG", "qty": 1, "stl": "electronics_plate.stl", "print_time_min": 25, "weight_g": 14, "notes": "для ESP32/IMU/FPV/VTX, snap-fit к деке"},
    {"slot": "Body posts", "material": "PETG", "qty": 4, "stl": "body_post.stl", "print_time_min": 12, "weight_g": 2, "notes": "крепёж кузова, M2.5 закладные"},
    {"slot": "Front bumper", "material": "TPU 95A", "qty": 1, "stl": "front_bumper.stl", "print_time_min": 18, "weight_g": 8, "notes": "TPU для амортизации ударов"},
    {"slot": "Rear bumper", "material": "TPU 95A", "qty": 1, "stl": "rear_bumper.stl", "print_time_min": 18, "weight_g": 8, "notes": "TPU"},
    {"slot": "Shock towers (front)", "material": "PETG", "qty": 1, "stl": "shock_tower_front.stl", "print_time_min": 15, "weight_g": 6, "notes": "крепёж амортизаторов спереди"},
    {"slot": "Shock towers (rear)", "material": "PETG", "qty": 1, "stl": "shock_tower_rear.stl", "print_time_min": 15, "weight_g": 6, "notes": "крепёж амортизаторов сзади"},
    {"slot": "Servo mount", "material": "PETG", "qty": 1, "stl": "servo_mount.stl", "print_time_min": 8, "weight_g": 3, "notes": "маунт PN-SRV-001"},
    {"slot": "Motor mount", "material": "PETG", "qty": 1, "stl": "motor_mount.stl", "print_time_min": 8, "weight_g": 3, "notes": "крепёж RC0820 + охлаждение"},
    {"slot": "Battery strap", "material": "TPU 95A", "qty": 1, "stl": "battery_strap.stl", "print_time_min": 6, "weight_g": 2, "notes": "TPU резинка для фиксации батареи"},
    {"slot": "Body shell (POC)", "material": "PETG", "qty": 1, "stl": "body_shell_poc.stl", "print_time_min": 90, "weight_g": 35, "notes": "тестовый кузов 0.8мм стенка; финальный — купить лексан"},
    {"slot": "Wire channels/clips", "material": "PETG", "qty": 4, "stl": "wire_clip.stl", "print_time_min": 8, "weight_g": 1, "notes": "фиксация проводов"},
    {"slot": "FPV camera mount", "material": "PETG", "qty": 1, "stl": "fpv_camera_mount.stl", "print_time_min": 10, "weight_g": 3, "notes": "крепёж Eachine C01 PRO, регулировка угла"}
  ],
  "filament_required": [
    {"type": "PETG", "qty_g_per_car": 95, "qty_g_total_4cars": 400, "color_suggestion": "чёрный матовый"},
    {"type": "TPU 95A", "qty_g_per_car": 18, "qty_g_total_4cars": 75, "color_suggestion": "чёрный"}
  ],
  "totals": {
    "buy_only_per_car_usd": 122.0,
    "buy_only_4_cars_usd": 488.0,
    "track_infra_usd": 200.0,
    "grand_total_usd": 688.0,
    "saved_by_printing_per_car_usd": 34.5,
    "saved_by_printing_4_cars_usd": 138.0
  }
}