Detailed 3D maps of the iconic and historic Notre Dame Cathedral in Paris, including shots from the “Assassin’s Creed: Unity”, hold out hope for accurate reconstruction after it was devastated by a massive fire Monday. Both the ceiling and the spire were destroyed, as well as internal woodwork, GPS World.
But the information to restore the cathedral is abundant. Besides photos, art historian Andrew Tallon used laser scanners to create an immaculately accurate model of the cathedral, as reported in this National Geographic feature.
Laser scans, with their exquisite precision, don’t miss a thing. Mounted on a tripod, the laser beam sweeps around the choir of a cathedral, for example, and measures the distance between the scanner and every point it hits. Each measurement is represented by a colored dot, which cumulatively create a three-dimensional image of the cathedral. “If you’ve done your job properly,” says Tallon, the scan is “accurate to within five millimeters [.5 centimeter].”
Tallon figured out how to knit the laser scans together to make them manageable and beautiful. Each time he makes a scan, he also takes a spherical panoramic photograph from the same spot that captures the same three-dimensional space. He maps that photograph onto the laser-generated dots of the scan; each dot becomes the color of the pixel in that location in the photograph.
As a result, the stunningly realistic panoramic photographs are amazingly accurate. At Notre Dame, he took scans from more than 50 locations in and around the cathedral—collecting more than one billion points of data.
Another source comes from a video game company. Immaculate models of the cathedral were collected for the creation of the best-selling “Assassin’s Creed: Unity,” where the hero/player is able to climb both the outside and inside of the massive edifice.