{"design":{"construction_jpy":17900000,"floors":1,"gross_floor_m2":56.0,"rooms":"1LDK + 屋外サウナ小屋","structure":"ログハウス (ノルウェースプルース 200mm) + 薪ストーブ + 屋外フィンランドサウナ","title":"群馬県北軽井沢 — 大字長日向 別荘地","total_jpy":20100000},"files":{"ifc":"/api/showcase/1hour-kitakaruizawa/bim.ifc","image":"/api/showcase/1hour-kitakaruizawa/image","json":"/api/showcase/1hour-kitakaruizawa/bim.json"},"schema":"BIM.HOUSE Real Listing v1","site":{"address":"群馬県吾妻郡長野原町大字長日向 (中軽井沢駅 車 22 分)","land_area_m2":580.0,"land_price_jpy":2200000,"lot_d_m":27.6,"lot_w_m":21.0,"zoning":"別荘地"},"source":{"fetched_at":"2026-05-09","type":"SUUMO public listing","url":"https://suumo.jp/tochi/gunma/sc_agatsumagun/"},"validation":{"geometry_includes":["Project + Site + Building hierarchy","1 storeys with slab + 4 walls each","1 entrance door (south wall, ground floor)","IfcRelContainedInSpatialStructure links per storey"],"ifc4_compliant":true,"tested_with":["FreeCAD 1.0","IfcOpenShell 0.7.0"]}}