How 3D scanning helped restore Notre Dame after the great fire

The 3D scanning of Notre Dame before the fire

Long before the fire, Notre Dame had been meticulously 3D scanned by art historian and preservationist Andrew Tallon. Using LiDAR (Light Detection and Ranging) technology, Tallon created a detailed point cloud model of the cathedral, capturing every arch, column and intricate feature with millimeter precision.

How the scanning process worked:

• LiDAR technology was used to map every surface of the cathedral by emitting laser pulses and measuring their return times.
• Point clouds were generated, forming a digital replica of the cathedral’s architecture.
• Accuracy within millimeters ensured that even the slightest details, from ornate sculptures to the curvature of vaulted ceilings, were recorded.

This digital blueprint would later become an essential reference for restoring Notre Dame to its original state.

1. Preserving architectural accuracy

The scans provided exact dimensions, ensuring that every rebuilt element matched the original structure with precision. This level of detail allowed craftsmen to accurately replicate intricate stonework, wooden beams, and stained glass windows, preserving the historical authenticity of the building.

2. Guiding structural stability assessments

Engineers relied on the digital model to assess damage and identify weakened areas that required reinforcement. By analyzing the scans, they could determine how much of the original structure could be salvaged, enabling a more strategic and informed restoration process.

3. Accelerating the rebuilding process

Having a detailed digital blueprint eliminated the need to rely solely on historical documents or photographs, allowing restoration teams to work more efficiently. Advanced fabrication techniques, such as 3D printing and CNC machining, were used to recreate destroyed sections with exceptional precision, significantly speeding up the reconstruction.

4. Future-proofing for preservation

The Notre Dame project showcased how digital scans can serve as long-term preservation tools, ensuring that accurate records of historic structures remain available for future generations. This same technology is now being used to scan other historic landmarks as a preventive measure, safeguarding their details before potential damage occurs.

The successful use of 3D scanning in Notre Dame’s restoration has inspired similar initiatives worldwide. Historic landmarks and cultural sites are now being digitized to safeguard them against future disasters, including:

• The Pyramids of Egypt – 3D models help monitor structural integrity over time.
• Machu Picchu, Peru – Scans assist in conservation planning and prevent environmental damage.
• The Statue of Liberty, USA – Detailed scans preserve the monument for future generations.