Notre-Dame had a billion-point scan. Someone still had to read it. / Our Blog / By Finulent Solutions Months before the 2019 fire, art historian Andrew Tallon died, leaving behind a laser scan of Notre-Dame with roughly a billion points. After the fire, restoration architects relied on it and called it a recording that still needs decoding. The cathedral reopened in December 2024. That matters for anyone working on historic buildings in the UK or Europe. A scan records where surfaces are. It can’t tell you what a wall is, what has been altered, or what a conservation architect can safely touch. People decide that, and a heritage BIM model is where those decisions get written down. Old buildings don’t draw straight. Historic buildings bow and lean, and later alterations sit on top of earlier ones that standard drawings often miss. A laser scan captures it all. Point cloud to BIM conversion then has to choose, and three choices come up before the first wall is modelled. As found or as intended? A wall with a visible lean can go in leaning or straight, and each suits a different use. How much detail? A vaulted ceiling holds more geometry than most budgets can model. The agreed level of development, such as LOD 300 or LOD 350, decides where the line falls. How is change shown? An alteration of uncertain date needs a way to say “probably,” not just “is.” The UK has guidance, but practitioners find it heavy. Historic England publishes two BIM for Heritage guides. One covers the historic building model. The other covers the Asset Information Model, which is built around conservation, repair and maintenance and comes with templates for organisational, asset and exchange information requirements. Both are still on its current guidance list. Industry research is less enthusiastic. Practitioners describe heritage BIM as still limited in use and the guidance as complex. Heritage work is estimated at £9.6 billion a year of UK construction output, which makes it a large market. Europe has no shared standard either. A 2026 research paper notes that no internationally recognised standard for heritage BIM exists, despite regional guidance such as Historic England’s. An EU-funded project, INCEPTION, built an open-standard platform for heritage models, but practice still differs by country. Energy rules add pressure. The recast EPBD allows exemptions for some categories, including protected and listed buildings, and how that works depends largely on national transposition, which was due on 29 May 2026. No member state had reported full transposition. ICOMOS published a report on the directive and cultural heritage in January 2026. Exempt or not, an owner needs accurate existing building modelling data before deciding what can be done. What the model should still say in ten years Geometry is only the starting point. Research on heritage BIM suggests a good model records each known or theorised change and marks where the evidence is thin. It also carries materials, condition notes and links to the maintenance plan. That is the idea behind the Asset Information Model. It should open in the formats the wider team uses, such as Revit and IFC, and follow ISO 19650 where the client requires it. Four questions before anyone scans What decision will the model support? Repair, retrofit, planning and maintenance each need different detail. What source data exists? A scan, a measured survey, old drawings, or a mix. Quality limits what can be modelled. Who interprets the ambiguous areas? Someone with conservation knowledge should sign off the model’s assumptions. Who looks after the model after handover? A model nobody updates stops being a record. Where Finulent fits Finulent’s BIM team supports architecture, survey and engineering firms with Scan to BIM and as-built survey modelling of existing buildings, turning point cloud data into Revit models. It can work from common formats such as E57 and Autodesk ReCap files and deliver in Revit and IFC, subject to scan quality and agreed scope. Conservation judgement stays with the conservation architect and the building owner. The modelling team turns the capture into something the project team can work from.
