PHOTOGRAPHY: ART GRAPHIQUE PATRIMOINE. ILLUSTRATION: MATTHEW GREENSTARTspecialising in 3D modelling of cultural
monuments, which scanned the
entire structure between 2010 and- The day after the fire, the French
government asked AGP to build a digital
version of Notre Dame as it had been.
To scan a site, AGP uses helicopters,
drones and terrestrial scanners. Laser-
grammetry and photogrammetry then
create “scatter plot” models – 3D recre-
ations made of billions of dots. Digital
recreation from the archives took AGP
two months, six “super calculators”, and
the 21-strong team’s full-time attention.
“Our data covered most of the
building, including all of the exterior,
the two bell towers, the organ, and the
entirety of the forest,” says Gaël Hamon,
a stonemason and the CEO of AGP. This
amounted to 50 billion 3D points, or one
to two per square millimetre. The model
for the forest alone counts three to five
billion points, captured in 150 different
scans. But that’s just the start: now that
the pre-fire cathedral lives on digitally,
AGP is working on an extremely detailed
3D “smart database” of the building as
it is now, with integrated information for
each element. Zooming in on a stained-
glass window, for instance, would list its
materials, date of construction, style
and any other relevant information.The technique, called BIM – Building
Information Modelling – will 3D-map the
damage and allow for reconstruction
simulations, although no restoration
work is expected to start before BIM
completion in early 2020.
“We are treating Notre Dame the way
a greatly traumatised patient would
be treated in hospital,” Hamon says.
“With the BIM, it’s getting everything:
MRI and medical scans, blood tests, a
full check-up. We can’t heal it without a
proper diagnostic.” Not only will the old
Notre Dame live on digitally: it will be the
essential blueprint for the restoration.
The Notre Dame fire was a tragedy,
but it did act as an advocate for the
pioneering techniques Hamon has been
working on for 25 years. In 1994, when
he founded AGP, scanning monuments
involved analogue photos. “We had to
enter all data, all the measurements,
by hand,” Hamon recalls. “Now we
have digital photos, we put everything
in the algorithm – it’s automatic.”
Since then, AGP has worked on more
than two thousand monuments in 18
countries, including the Royal Albert
Hall in London, the Palmyra ruins in
Syria, and the Louvre museum in Paris.
Soon, the company hopes to open
a cultural space offering virtual reality
visits of heritage monuments. But
right now, it’s all about Notre Dame.
“Our measures will give architects the
necessary tools to make a ‘before/
after’ diagnostic for the restoration,”
Hamon says. Healing a cathedral that
took more than a century to build cannot
be rushed. Pauline Bock artgp.frRight: a FARO laser
scanner in the
nave of Notre Dame.
Its 3D map of
the fire damage will
be compared to
AGP’s earlier scans
of the undamaged
cathedralSTART 042EARLY ADOPTERS WIRED asks three entrepreneurs about their newest podcast discoveriesRiya Grover
CEO, FeedrBruce Pannaman
CTO, StorkCardAdam Dodds
CEO, Freetrade“I love listening
to other founder
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Decode’s recent
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which discusses
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ideas for customer
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providing value for
new parents. If it’s
not fun, you’re not
doing it right.”“Michael Lewis’s
podcast, Against
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the ways we
perceive regulation
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Magic Shoebox’,
on the lack of
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Sabrina Weiss11-19-STNotreDame.indd 34 24/08/2019 02:53