"Buildings": {
  "type": "array",
  "minItems": 1,
  "maxItems": 1,
  "title": "Buildings",
  "default": [
    {
      "Floors": [
        {
          "Floorplan": {
            "Footprint": {
              "DesiredAspectRatio": {
                "x": 1,
                "y": 1
              }
            },
            "Ceiling": {"Height": 3},
            "Rooms": [
              {
                "Type": "Living",
                "Name": "My_Living_Room",
                "OriginalName": "My Living Room",
                "DesiredShape": {
                  "Area": 20,
                  "AspectRatio": {
                    "x": 1,
                    "y": 1
                  }
                }
              }
            ],
            "DesiredConnections": []
          },
          "Interior": {
            "Doorways": {
              "DoorwaySets": []
            },
            "Flooring": {
              "MaterialSets": []
            },
            "Walls": {
              "MaterialSets": []
            },
            "Furniture": {
              "FurnitureArrangements": []
            }
          }
        }
      ]
    }
  ],
  "items": {"$ref": "#/definitions/BuildingTemplate"}
}

 "items": {"$ref": "#/definitions/BuildingTemplate"}