{
 "title": "Eton College exterior reconstruction",
 "edition": "2026-09-10-r3",
 "status": "Source-informed reconstruction on a modular geometry kernel; not a measured digital twin",
 "coordinateSystem": {
  "originLongitude": -0.60855,
  "originLatitude": 51.4918,
  "x": "east metres",
  "z": "south metres",
  "verticalDatum": "simplified level ground; not surveyed"
 },
 "sources": [
  {
   "id": "osm",
   "title": "OpenStreetMap contributors: Eton and surrounding context",
   "url": "https://api.openstreetmap.org/api/0.6/map?bbox=-0.6190,51.4860,-0.6000,51.5010",
   "license": "ODbL",
   "attributionURL": "https://www.openstreetmap.org/copyright",
   "use": "Building outlines, roads and mapped trees"
  },
  {
   "id": "eton-plan",
   "title": "Eton College central-area plan, 2025",
   "url": "https://www.etoncollege.com/wp-content/uploads/2025/07/Central-Area-Map-Eton-College-2025.pdf",
   "use": "Reference only: building identification and spatial relationships"
  },
  {
   "id": "rchme",
   "title": "RCHME Buckinghamshire South (1912), Eton, pp142\u2013153",
   "url": "https://www.british-history.ac.uk/rchme/bucks/vol1/pp142-153",
   "use": "Historical architectural description and internal dimensions"
  },
  {
   "id": "historic-england",
   "title": "Eton College buildings, listing1290278",
   "url": "https://historicengland.org.uk/listing/the-list/list-entry/1290278",
   "use": "Reference only: architectural materials and building history"
  },
  {
   "id": "polyhaven",
   "title": "Poly Haven CC0 surface scans and environment lighting",
   "url": "https://polyhaven.com/license",
   "use": "Generic scanned material proxies; not Eton-specific capture. HDR environment is lighting-only."
  }
 ],
 "measuredReferences": [
  {
   "feature": "Chapel choir",
   "measurement": "150 \u00d7 40 feet internally (45.72 \u00d712.192m)",
   "source": "rchme",
   "limitation": "Historical INTERNAL dimension, not present exterior footprint"
  },
  {
   "feature": "Chapel",
   "measurement": "Eight choir bays",
   "source": "rchme"
  },
  {
   "feature": "Cloister Court",
   "measurement": "Originally approximately90 feet square",
   "source": "rchme",
   "limitation": "Historic dimension; court shape reconstructed from OSM"
  }
 ],
 "derived": [
  "Horizontal building footprints",
  "Approximate campus orientation",
  "Relative placement of main ranges"
 ],
 "estimated": [
  "Building heights where OpenStreetMap carries no height or level tag",
  "Roof pitches and forms",
  "Window spacing, proportions and tracery",
  "Chapel buttress projection, parapet, pinnacles and turret heights",
  "Lupton's Tower turret, cupola, oriel and clock proportions",
  "Upper School arcade bay spacing, cornice and quoins",
  "College range eaves heights and window types, inferred from position in the mapped ring",
  "Cloister arcade bay spacing and walk depth",
  "Gate openings and traverse routes",
  "Surface materials of the yard, court and walks",
  "Statue and cannon form; fine sculpture is not reproduced",
  "Street furniture positions other than those following a mapped way",
  "Tree species and positions beyond the 50 mapped nodes"
 ],
 "notReconstructed": [
  "Interiors",
  "Underground spaces",
  "Fine carvings",
  "Surveyed elevation changes",
  "Full campus coverage"
 ],
 "buildingCount": 367,
 "sourcesCompared": true,
 "surveyAccuracyEstablished": false,
 "photographicReferences": [
  {
   "file": "quadrangle.jpg",
   "description": "School Yard from chapel side looking north: Lower School, founder statue, Upper School corner",
   "author": "jtriefen",
   "license": "CC BY 2.0",
   "license_url": "https://creativecommons.org/licenses/by/2.0/",
   "source": "https://commons.wikimedia.org/wiki/File:Eton_College_quadrangle.jpg",
   "date": "2006-07-15",
   "inspected": true
  },
  {
   "file": "lupton.jpg",
   "description": "Lupton's Tower, west face frontal, photographed from School Yard",
   "author": "Graham Horn",
   "license": "CC BY-SA 2.0",
   "license_url": "https://creativecommons.org/licenses/by-sa/2.0/",
   "source": "https://commons.wikimedia.org/wiki/File:Eton_College,_Lupton's_Tower_-_geograph.org.uk_-_2675613.jpg",
   "date": "2011-10-26",
   "inspected": true
  },
  {
   "file": "upper-school-west-miscaptioned.jpg",
   "description": "Actually Upper School west facade; source title incorrectly labels Chapel. Verified visually.",
   "author": "Paul Gillett",
   "license": "CC BY-SA 2.0",
   "license_url": "https://creativecommons.org/licenses/by-sa/2.0/",
   "source": "https://commons.wikimedia.org/wiki/File:Eton_College_Chapel_-_geograph.org.uk_-_2323968.jpg",
   "date": "2011-03-24",
   "inspected": true
  },
  {
   "file": "chapel-wide.jpg",
   "description": "Chapel from south",
   "author": "Len Williams",
   "license": "CC BY-SA 2.0",
   "license_url": "https://creativecommons.org/licenses/by-sa/2.0/",
   "source": "https://commons.wikimedia.org/wiki/File:Eton_College_Chapel_-_geograph.org.uk_-_4057486.jpg",
   "date": "2014-07-04",
   "inspected": true
  },
  {
   "file": "chapel-plain.jpg",
   "description": "South side of St Marys Chapel",
   "author": "Jonnrobb",
   "license": "CC BY-SA 3.0",
   "license_url": "https://creativecommons.org/licenses/by-sa/3.0/",
   "source": "https://commons.wikimedia.org/wiki/File:Eton_College_Chapel.jpg",
   "date": "2011-05-13",
   "inspected": true
  },
  {
   "file": "chapel-mk.jpg",
   "description": "Chapel roof and south facade from Windsor Castle; good for roof ridge and east twin lantern silhouette",
   "author": "Martin Kraft (photo.martinkraft.com)",
   "author_url": "https://photo.martinkraft.com/",
   "license": "CC BY-SA 3.0",
   "license_url": "https://creativecommons.org/licenses/by-sa/3.0/",
   "source": "https://commons.wikimedia.org/wiki/File:MK17792_Eton_College_Chapel.jpg",
   "date": "2014-08-12",
   "inspected": true
  }
 ],
 "scope": {
  "description": "Eton main-campus and surrounding-town context extract; includes neighbouring property, not a school ownership boundary or proof of complete estate coverage",
  "includesDetachedDorneyLake": false,
  "coreRecordsPreserved": 35,
  "counts": {
   "preservedCoreBuildingRecords": 35,
   "addedContextBuildingRecords": 332,
   "namedAssociatedBuildingRecords": 49,
   "totalBuildingRecords": 367,
   "landscapeAreas": 138,
   "mappedTreePoints": 50
  }
 },
 "dossierReview": {
  "catalogueItems": 339,
  "drivePlates": 216,
  "webPhotographs": 123,
  "photographicPlatesVisuallyReviewedInBoundedAudit": 33,
  "independentCurrentCaptureCountEstablished": false,
  "notes": [
   "Historical views, proposed renderings and uncertain building identifications are retained as qualified references.",
   "Private Drive audit metadata is not distributed with the website."
  ]
 },
 "runtime": {
  "renderer": "Three.js 0.180.0 WebGL",
  "materials": "Six CC0 scanned colour/normal/roughness sets",
  "lighting": "HDR environment reflections, authored daylight, AgX tone mapping; optional GTAO at High detail",
  "fallback": "Explicitly selected software preview when WebGL is unavailable",
  "GPUperformanceVerified": false,
  "geometry": "Metre-scaled mapped footprints with estimated architectural detail; spatially batched for visibility"
 },
 "unresolved": [
  "Present-day facade-by-facade measured validation",
  "Accurate sculpture, carvings and full Gothic tracery",
  "Surveyed topography, steps and connected interior layouts",
  "Complete vegetation capture and species identification",
  "GPU visual and performance testing on target devices",
  "GTA VI visual parity; current reconstruction remains below photorealistic target"
 ],
 "validation": {
  "geometryAndCollision": "Automated navigation and release-integrity checks passed on 2026-09-10; see qa/eton-explorer/STATUS.md for scope.",
  "offline": "Three Cycles CPU diagnostic views inspected; not proof of browser appearance or frame rate.",
  "visualTargetMet": false,
  "architecturalSurveyAccuracyEstablished": false
 },
 "reconstruction": {
  "kernel": "public-site/src/lib/eton/build/kernel.ts",
  "modules": {
   "estate": "All non-landmark mapped footprints: wall panels with cut openings, distance-field roofs, chimneys, per-building tints, three distance tiers",
   "ground": "Landscape, water channels with banks, roads with kerbs and raised pavements, centre lines, historic-centre surfaces, mapped boundary treatments",
   "landmarks/chapel": "College Chapel: offset buttresses, Perpendicular windows, embattled parapet, pinnacles, ante-chapel turrets, yard steps",
   "landmarks/college": "College ranges classified edge by edge, Cloister Court arcade and walk, library elevation, College Hall",
   "landmarks/lupton": "Lupton's Tower: octagonal turrets with lead cupolas, stacked oriels, clock, vaulted gate passage",
   "landmarks/upperSchool": "Upper School: open arcade, cornice, parapet, quoins, carriage arch, doorcase",
   "landmarks/schoolYard": "Founder's statue with railings, and the cannon",
   "vegetation": "Four instanced procedural species from mapped tree nodes, wood and park polygons, riverbanks and the Slough Road avenue",
   "props": "Burning Bush, street lamps, bollards, benches, railings, gate lanterns, rainwater goods"
  },
  "lighting": {
   "sunAzimuthDegrees": 215.86,
   "sunElevationDegrees": 48.16,
   "derivation": "Brightest pixel of the CC0 daylight HDR, so shadows, sky and reflections share one sun",
   "shadows": "Three cascaded shadow maps following the camera",
   "ambientOcclusion": "Ground-truth AO at the high detail setting"
  }
 },
 "generatedSurfaces": [
  {
   "key": "brick_tudor",
   "tileMetres": [
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    1.5
   ],
   "notes": "Tudor red brick in English bond with vitrified-header diaper and lime mortar. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
    "colour": {
     "pixels": "2048x2048",
     "bytes": 87872,
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  {
   "key": "brick_plain",
   "tileMetres": [
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   ],
   "notes": "Georgian red brick in stretcher bond with pale mortar. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  {
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   "tileMetres": [
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   "notes": "Darker Victorian brick in English bond. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  },
  {
   "key": "ashlar",
   "tileMetres": [
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   ],
   "notes": "Coursed cream limestone ashlar with fine joints and tooling. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  },
  {
   "key": "tile",
   "tileMetres": [
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   ],
   "notes": "Clay plain tiles, double-lapped, mixed weathering. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  },
  {
   "key": "lead",
   "tileMetres": [
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   ],
   "notes": "Lead sheet roofing with rolls at 0.6 m and patina. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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    "normal": {
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  },
  {
   "key": "tarmac",
   "tileMetres": [
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   ],
   "notes": "Bituminous road surface with patch repairs. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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   }
  },
  {
   "key": "flagstone",
   "tileMetres": [
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   ],
   "notes": "York-stone paving slabs in mixed sizes, worn centres. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  {
   "key": "cobble",
   "tileMetres": [
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   ],
   "notes": "Granite setts in bowed courses. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  },
  {
   "key": "bark",
   "tileMetres": [
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   ],
   "notes": "Vertically fissured broadleaf bark. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  {
   "key": "hedge",
   "tileMetres": [
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   ],
   "notes": "Clipped dense hedge surface. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  },
  {
   "key": "leaf",
   "tileMetres": [
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   ],
   "notes": "Alpha atlas of leaf clusters: lime, oak, willow, mixed. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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  },
  {
   "key": "lawn",
   "tileMetres": [
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   ],
   "notes": "Mown turf with clumping, thin dry patches and moss. Generated from published descriptions of the fabric; not a photographic scan of Eton.",
   "maps": {
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 ]
}