Clunypedia

The largest church in the world, back on its footprint after two centuries.

For some six hundred years the church of Cluny Abbey was the largest one in Christendom — until St. Peter’s in Rome finally overtook it. Then the Revolution turned it into a stone quarry and it was demolished. I led the build of the AR (Augmented Reality) app that puts it back: stand in the field where the nave once rose, raise the device, and the lost church is there again — inside and out — for the first time in two hundred years.

Twelve years, across Europe.

The Cluny reconstruction was one piece of a body of heritage capture spanning more than a decade. From 2009 to 2020 I criss-crossed Europe photographing the Cluniac network — the priories and abbeys tied to Cluny between the 10th and 16th centuries — and gathered digital copies of numerous buildings and artefacts in 3D, mapped at clunypedia.com.

At Cluny itself the work fed Clunyvision, then ClunEtour, a guide to the medieval city: historical context, ancient engravings, 3D models of sculptures long gone from the site, and interactive panoramas of the vanished church. It ran at the tourist office for roughly ten years; some 100,000 visitors pass through each year. (The Cluny digitization was a team effort I contributed to; the AR app was a Paztec — the startup I co-founded — build I led.)

My first digital twin, before I had the word for it.

The instinct went back further. In 2007, for my final-year project, I digitized a ruined chapel — the Chapelle de Cruzille — and rebuilt its original state virtually from the capture data. When the real chapel was physically restored a few years later, I re-synced the model in 2012 to match what had actually changed: a digital counterpart tracking its physical original through time.

How it’s made.

Across these I worked in hybrid capture — terrestrial LIDAR (Faro Focus3D, Trimble scanners; a Faro articulated arm for sculpture) fused with full-frame photogrammetry in RealityCapture (now RealityScan), and Agisoft: LIDAR for high precision geometry, photography for colour and texture, each covering the other’s blind spots. At the rigorous end, I digitized the entire Abbey of Romainmôtier in Switzerland single-handed by manual photogrammetry — matching corresponding features across more than 3,000 photographs by hand — into a fully textured model, inside and out, that was used in a documentary film. At Cluny I field-tested the photogrammetry engine that would later become Acute3D, then Bentley ContextCapture — its inventors came to site to trial it with me, including aerial captures flown from helium balloons, before it was even a company.