Scanning of the building by Andrew Tallon
In 2015, the Vassar College professor Andrew Tallon scanned the whole building of the Notre Dame Cathedral in great detail, using a laser technology. He died in November 2018, months before the fire — and now, in the aftermath of this tragedy, it is believed that his work will be incredibly valuable for the restoration of the building.
Tallon, who died of cancer on November 18, 2018, pioneered the use of laser technology and advanced imaging techniques and built a digital model of Notre Dame. His work with images captured by the drone-borne, 360-degree spherical cameras he deployed at the 800-year-old cathedral continued until his death. In a publication following his death, the Society of Architectural Historians said Tallon “was esteemed worldwide as an innovative scholar of French Gothic art and architecture, one who introduced new digital techniques to the analysis and re-creation of the spatial archaeology of medieval buildings. In all his work, he was an inspired and generous educator who brought the past to life in vivid and meaningful ways.” — Larry Hertz for Vassar College Stories
And here are more videos on the subject. The first one shows professor Tallon himself explaining the technology he used on the National Cathedral, in Washington, D.C.