By Luke Carothers

Notre-Dame de Paris is one of the world’s greatest examples of French Gothic architecture still remaining.  Known to many simply as Notre Dame, the cathedral is located in Paris and holds the designation as the world’s most visited place.  Construction on Notre Dame began in the 12th century, but the project wasn’t completed for over 300 years.  While the cathedral boasts no shortage of stunning examples of French Gothic architecture, this three-century construction process means that there are also older styles incorporated into the structure such as Renaissance and Naturalism.  This variety of styles is one of the many reasons why Notre Dame continues to be lauded for its beauty and elegance.

In its long, storied life, the Notre Dame cathedral has been both an arena for important history events and a setting for genre-defining literature.  This is both the place where Napoleon’s coronation took place and that inspired Victor Hugo to breathe life into the story of the Hunchback that found solace in the structure’s romantic architectural setting.  Notre Dame’s immense importance to cultural, political, and social history is partially reflected in historical efforts to continuously maintain and revitalize the space.  This revitalization process began even as the first construction phases were progressing.  The decision to remove the previous church and erect Notre Dame was ultimately made based on the rapid pace at which both the population and cultural importance of Paris were growing.  This meant that, in many cases, alterations were made to original plans to reflect the trends that existed in French architecture.

The first major restoration project after the cathedral’s completion began in 1844 when King Louis Philippe ordered it done following the enormous success of Victor Hugo’s The Hunchback of Notre Dame.  Before the novel’s publication, Notre Dame had fallen into significant disrepair.  In the centuries before this first restoration project, several iconic aspects of the original structure fell into disrepair and were removed, such as the spire.  This tremendously expensive 19th century restoration process not only added a larger and more ornate spire, it also added a new sacristy building and further decorations to restore the structure to its original beauty.

Several other restoration projects have taken place over the centuries such as cleaning the building’s exterior to combat the aesthetic effects of climate change on its exterior, removing some of the decaying or loose decorations, and installing measures to deter pigeons.  In 2016, a project was launched to make restorations to the structure’s roof and spire, a project that was scheduled to last between five and ten years.  It was during this renovation project that tragedy struck.  In April 2019, a small fire broke out just beneath the cathedral’s roof and quickly spread, engulfing both the spire and roof in flames.  By the time the fire was contained, the cathedral’s spire and roof had been completely destroyed, and there was significant damage to the upper portions of its stone walls.

Befitting its status as a world icon, the Notre Dame Cathedral fire elicited a global outpouring of both grief and support.  Financial donations and other forms of support were offered from individuals and organizations from every corner of the globe.  One person who was in a unique position to offer support in restoring and rebuilding this world icon was Andrew Anagnost, CEO of Autodesk.  Along with organizing relief and sending financial donations, Anagnost knew that Autodesk could also help by using their technology.  Anagnost reached out to his coworker Nicolas Mangon.  Mangon, a native of France who spent six years studying structural engineering less than who blocks from Notre Dame, considers the structure “part of [his] DNA” and agreed to help in any capacity.

As Autodesk’s Vice President of AEC Strategy, Mangon knew that creating a BIM model would help the restoration process with managing construction sequences and logistics and to help with fluid dynamics calculations for stability.  This meant that a detailed model of the Notre Dame Cathedral had to be created.  While there were a few scans of the structure prior to the fire, Autodesk funded more scans inside the building.  This data allowed Autodesk to create a 3D BIM of the Notre Dame Cathedral before the fire.  Ultimately, this modeling sequence as well as cleaning the inside of this structure lasted nearly three years, finishing earlier this Fall.  During this process, Mangon says Autodesk also aided efforts by offering their tools to anyone involved in the project and providing advisors on their usage.

While the process of restoring the cathedral is still ongoing, the areas that immediately surround it are also being updated.  Because this is one of the most heavily trafficked areas in the world, the space has had long running issues with parking, traffic, and noise.  To select a plan for the redesign of this area surrounding Notre Dame, the City of Paris held an architectural contest in 2021.  The goal was to reimagine the urban landscape surrounding the cathedral.  Again in this endeavor, Autodesk provided critical assistance, building a complete digital twin but for the areas surrounding the cathedral.  The digital documents associated with the competition, including the models, were also available for use by the contest’s four participants, allowing them to collaborate with the City of Paris and Autodesk in real time via the Autodesk Construction Cloud platform.  The winner of this contest–Bureau Bas Smets–was announced earlier this year in June.  With the winning project selected, the City of Paris is looking to begin construction on the site in 2024 with completion scheduled for 2028.

The catastrophic fire that broke out in the Notre Dame Cathedral in 2019 sent reverberating shockwaves throughout the world.  As the designers of the world around us, these shockwaves seemed to reverberate stronger, and the AEC industry’s response to the crisis is indicative of our ability to rise and respond to the moment.  As a function of the digital era, the tools we create, master, and employ can be deployed globally to affect change.  Autodesk’s response to the Notre Dame Cathedral fire is a hopeful glimpse into how the AEC industry can change the future for the better, adapting our tools and sharing them on a global scale.


Luke Carothers is the Editor for Civil + Structural Engineer Media. If you want us to cover your project or want to feature your own article, he can be reached at lcarothers@zweiggroup.com.