
The Laser Scans That Could Help Rebuild Notre-Dame Cathedral - xoa
https://www.theatlantic.com/technology/archive/2019/04/laser-scans-could-help-rebuild-notre-dame-cathedral/587230/
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theoh
There's a lot of speculation in this article. I don't know what documentation
exists of Notre Dame's roof structure, and from the way these (foreign)
experts are talking, they don't know either.

A point cloud scan is a particular kind of record, one which doesn't include
information about construction techniques or materials. It's good for
capturing geometry, to the point of excessive accuracy.

This situation is a bit like analysing a plate of food using a mass
spectrometer. The data is incredible but it doesn't overlap at all with what
went on in the kitchen or on the farms where the food was grown. It doesn't
tell you how to recreate the meal.

Point clouds are nice to have, but they are really a souped-up form of
photogrammetry, and not equivalent to a survey performed by an expert human.

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xoa
The National Geographic article from 2015 [1] was pretty interesting at the
time and has been getting passed around again in light of the fire. But I had
no idea that Prof. Tallon passed away from cancer just last November. A bit of
an extra pang on top of the tragedy, though what an immediate extra bit of
legacy to leave behind too.

I would love to see that kind of fairly automated 3D laser scan tech become
more affordable and systematically used though. I worked at a firm that did
some historical restoration work on a 19th century building, nothing remotely
on the scale or significance of Notre-Dame but still beautiful in its own
right. At the time I looked at this tech, it would be useful both as a
backstop in case of disaster but also for better CAD work and even as VR to
give another option to view wonderful architecture to wider audiences. Nothing
beats going in person, but not everyone can go (even ignoring travel cost,
there is wear and tear to think about) and I don't think it's bad to have
another good option. It might be an efficient use of resources for nations to
fund a set of systems for national historic societies or the like that could
then lend them out for a few days to a week at a time systematically to
recognized registered historical landmarks, and then have the resulting raw
data be available as a public resource.

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1: [https://news.nationalgeographic.com/2015/06/150622-andrew-
ta...](https://news.nationalgeographic.com/2015/06/150622-andrew-tallon-notre-
dame-cathedral-laser-scan-art-history-medieval-gothic/)

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cimmanom
Perhaps there are other historical buildings we should scan just in case
something similar happens, be it war, earthquake, fire, or whatever?

