Laser Scanning Reveals Cathedral’s Mysteries | National Geographic

When you're working on medieval buildings, it's difficult to have the impression that you can say anything new. Because they've been looked at and written about for ages. I've been interested in the way Gothic buildings stand up, the way they handle themselves structurally. And unfortunately for me, there's nothing written about it. Masons never stopped at the end of the day and said, well, I built my cathedral this way because. And so I've been using more sophisticated technology these days to try to get new answers from the buildings. The best technology that could solve certain problems like this was the laser scanner. It allows one, really, for the first time in the history of writing about Gothic architecture to say things, I would say, with relative certainty. So the way it works is I had to set up a network of targets, which are just geolocated points in space. Yeah, that should be all right. And you define the density of the scan, the resolution of the scan. In other words, how many x, y, z coordinate points in the space do you want to acquire? And then you let it rip. So what the laser scan actually does is it sends out a beam. And it measures the amount of time that it takes for the beam to be admitted from its little laser device to whatever it hits. And then the time that it takes to come back. So it's doing this at a speed of hundreds of thousands of times a second. Yeah, we're actually talking to the scanner. That's good. So it generates a whole cloud of data points that's extremely rich. I've been wanting to come to National Cathedral for a few years now. They incorporated the widening refinement. That is, the uprights are not perfectly upright, especially just behind us in the crossing area. That is, in the intersection of the two major vessels of the church. So right away, you get a pretty interesting representation of the interior. You can measure your way into articulating the exact curvature of this thing. And once you realize the curvature, then you can project it on up. So that's the smoking gun. The verticals go up, the great piers go up, and then they start slowly to bend outwards. Now, to put this in perspective, it's a bit of a head-scratcher as far as a mason is concerned. You ask a mason to build something out of plum, he'll look at you like you're nuts. Froman, the architect of the cathedral, sensed that he didn't want something perfect because there was an element of kind of beauty in that. Gothic building, 12th century or 13th century building, you wouldn't look twice at that because that's just the way they built. But here, we know that they were trying to do it that way, and they could do it otherwise. And that's what's interesting about it, that they're deliberately trying to build crooked. So we have a wonderful combination in the National Cathedral of this aesthetic built in the mind of William Goodyear, concocted, you could say, based on a misreading of the evidence, but in service of an aesthetic that really does still stand. I see it as a way of mapping space, of doing archeology that is looking back in time. I'm not standing down below and I'm sitting with my jeep. That actually looks like it's bending out of place. With this, you can say that is bending out of place. For me, it's a giant detective puzzle. I look at this big stone mass, stone, iron, mortar, whatever, and I try to say, well, how did they do it? It's the age-old sort of fascination that really goes back to the fascination that I felt as a child and a nine-year-old kid looking at this big stone building, Notre-Dame, and saying, how did they do that?