The reopening of Notre-Dame de Paris Cathedral to the public, more than 5 years after the fire, is an opportunity to review the contribution of new technologies to this titanic reconstruction project. Autodesk is one of the companies that participated through financial and technological sponsorship. Explanations from Emmanuel di Giacomo, head of BIM ecosystem development at Autodesk for Europe.
In April 2019, after the Notre-Dame de Paris fire, many companies looked for ways to help. Beyond a financial donation, the amount of which remains confidential, the American company Autodesk also wanted to set up technological sponsorship.
Initially, Autodesk tied a partnership with the French company Art Graphique et Patrimoine, specialized in the reconstruction of 3D models, to create a BIM model of the cathedral using drones and point clouds. The objective: to facilitate the planning and management of the reconstruction site.
The BIM model of Notre-Dame de Paris, “ the largest model of a historical monument made in the world »
« You should know that the BIM model of Notre-Dame de Paris is the largest model of a historical monument that has been made in the world. So it’s something quite exceptional and gigantic. It's the most detailed, largest and heaviest model in the entire world, so it's truly a first », introduces Emmanuel di Giacomo, head of BIM ecosystem development at Autodesk for Europe, and architect by training.
Autodesk and Art Graphique et Patrimoine were quickly faced with a first challenge: the absence of 2D plans and documents for the cathedral.
« You would think there were documents, plans, sections, etc., but there were no 2D documents at all. So, one of the first missions, particularly from Graphic Art and Heritage, was to recreate a certain number of 2D documents from the point clouds that had been made. So, there are plans, sections, elevations of all the faces of Notre-Dame which were made using AutoCAD », Explains Emmanuel di Giacomo.
Credits: Public establishment in charge of the conservation and restoration of Notre-Dame de Paris Cathedral / Graphic Art & Heritage / Autodesk
Valuable help for logistics
Once created, the BIM model was used in particular to position the cranes, remove the old scaffolding and install the new one, but also anticipate the unloading of materials.
« This BIM model made it possible to reflect – always in relation to on-site logistics – where position water inlets, water discharges for the site », says Emmanuel di Giacomo.
Autodesk also donated software and made its teams of experts available to help the teams of the public establishment in charge of the reconstruction of Notre-Dame to familiarize themselves with BIM.
This digital model was then entrusted to the Scientific and Technical Building Center (CSTB), so that it can test the wind resistance of the new spire.
The surroundings of Notre-Dame de Paris also affected
In parallel with the reconstruction of the cathedral, Autodesk formed a partnership with the City of Paris in 2021 to “reinvent the surroundings of Notre-Dame”. Four teams made up of town planners, architects and landscapers were in the running to have their redevelopment project selected.
The company specializing in BIM then made available a 3D model of the cathedral and its surroundingsso that the competing teams can work on the same basis – the Belgian landscaper Bas Smets having ultimately won this international competition.
But what about the contribution of these new technologies to the maintenance and future upkeep of the cathedral?
Emmanuel di Giacomo tells us the possibility of creating a digital twin of Notre-Dame to manage the life cycle of the cathedralbut also maintain heating, ventilation, air conditioning (HVAC), plumbing, and fire safety systems.
BIM widely adopted for heritage renovation
Before Notre-Dame de Paris, Autodesk was not its first participation in the restoration of a historic monument. Its software has notably helped to the renovation of the Grand Palais, the Cité des sciences et de l'industrie, the Bourse du Commerce, the Center Pompidou, the roofs of the Louvre, and even the surroundings of the Eiffel Tower.
In terms of religious buildings, she has also worked with Art Graphique et Patrimoine tothe reconstruction of the spire of the basilica of Saint-Denis.
« The entire stone spire was reconstructed with our Autodesk Inventor solution, which is a mechanical solution. It's over 20,000 stones, and each of the stones is numbered. The CNC machines will cut each of the stones, so these are extremely complex cuts », explains the BIM specialist.
Digital transition: France’s delay
Asked more broadly about the adoption of new technologies by French construction companies, Emmanuel di Giacomo underlines that most of the majors, such as Vinci, Bouygues or Eiffage, have adopted them.
« All large companies are standardized in BIM, and continue to make enormous progress. They are investing more and more in this area. They no longer start a project in a manner “classic”that is to say in 2D. And they do it even if it is not requested by the project owner », notes the specialist.
On the other hand, the digital transition is struggling to become more widespread among small construction companiesmainly due to psychological and financial obstacles, according to the expert.
« There is indeed a psychological brake which is obvious. People don't like to change, and above all in France, we are very resistant to change in general», observes Emmanuel di Giacomo.
« Cost can be one of the reasons, but it is not necessarily a justified reason, because, for example, with us there are BIM tools from 50 euros per month», he emphasizes, while recognizing that small businesses do not necessarily favor this type of investment in a context of economic crisis.
According to him, this delay by France could be explained in particular by the absence of regulatory obligation to use BIM for public procurement, unlike other European countries.
« I think it is also linked to the fact that France is the only country where you do not have a BIM obligation for public contracts. As a result, this did not necessarily encourage VSEs and SMEs, unlike large companies which – being in a competitive international context – were obliged, and also to survive, to review their way of working. “, he believes.
And to add: “ You should know that now, almost all European countries, such as Germany, England, Spain, Italy, Switzerland or the Scandinavian countries, have obligations related to BIM ».
Promote high value-added tasks and the use of data
For the expert, it is urgent to adopt BIM and artificial intelligence, particularly for avoid low-value-added tasks, retain and use data efficiently, and increase productivity : « We realized that professionals were losing the equivalent of 14 hours per person per week. So around a third of time is wasted on low value-added tasks, which is enormous. Errors that are linked to the non-use of BIM or the non-use of advanced technologies such as AI, this generates more than 280 billion dollars in losses at the construction site level “, he emphasizes.
« Finally, what is shocking is that without these technologies, 96% of data that is generated during the design and construction phases is lostwhile typically artificial intelligence feeds on this data », he concludes.
Comments collected by Claire Lemonnier
Photo of one: Adobe Stock
