3D Model of Historic City

With an area of 30 sq. km. and set beautifully between the Pyrenees mountains and the ocean, Pau is the main city of the Pau Béarn Pyrénées Agglomeration council (which spans 31 councils and covers close to 400 sq. km.) Known as “The City of Art & History”, Pau has always had an innovative & progressive approach to adopting new technology. As part of their smart city approach, the agglomeration council actively develops and maintains a repository of digital data to improve knowledge, management and the prospective development of its heritage and its territory.

After a world-wide capability search and an international competitive tendering process in 2019, the agglomeration commissioned Aerometrex and its partner French company IGO SAS to produce a 3D model of the old city, including its historic castle, at a resolution approaching a few millimetres in pixel size. Aerometrex began working on the project in June 2019 and the final 3D model was released in the beginning of 2020.

Multiscale 3D Mesh Model of the city of Pau, by Aerometrex

This 3D city model of Pau, Southern France, is a multi-scale 3D mesh model generated from helicopter, drone and ground level capture

This project was a ground-breaking implementation of the science of massive multi-ray photogrammetry, involving the geometric reconstruction of more than 100,000 2D images taken from helicopter, drone and on foot. The model delivered resolutions ranging from 2cm up to 3mm, all stitched into a single 3D city mesh, enabling seamless interaction by users. The ability to process this massive volume of data (over 5TB) generated by these 3 perspectives over a whole city centre into a photo-realistic 3D environment provides users with an unparalleled immersive visual experience. The City of Pau was captured from a helicopter platform by Aerometrex and completed with drone captures over specific landmark buildings such as the Castle as well as street-level capture in the old town.

Triangulation was performed using the powerful capability of Agisoft Metashape and the reconstruction of the 3D mesh performed in Bentley ContextCapture. Artefacts such as cars, people and distorted glass windows and facades were corrected to generate a clean, accurate and seamless multiscale 3D mesh. The resulting 3D meshes were integrated into the interactive 3D platform Skyline TerraExplorer Pro/SkylineGlobe along with additional GIS information and geospatial data to provide internal and external stakeholders with a desktop/online data portal and powerful 3D capabilities including analysis, design and communication tools.

Jean-Michel Lopez, the Project Manager from the client’s side highlighted the multitude of opportunities that this 3D model opens to their community, businesses and individuals. Some of these are listed below:

  • Urban planning: It is in town planning that the 3D model offers the most direct applications. Architects or engineers will be able to understand the positioning of a building before its construction in a dynamic context. It is possible to entrust sections of the model to these companies so that they can insert digital sketches within the framework of building permits. This would allow all stakeholders to observe the real estate project from various angles: facades, colours, textures of materials, etc. Urban assets are mapped with utmost accuracy within the 3D model and their real-time status can support numerous maintenance teams and service providers. Public decision makers will also have a tool to anticipate urban development and land use planning
  • Transportation and traffic: The region’s public transport services would be among the most interested users: they will have the possibility of foreseeing the impacts of a change in direction of traffic on an arterial route. Similarly, the Mixed Urban Transport Union will be able to virtually drive its buses through the model in order to determine optimal paths.
  • Economics: In tourism, the model can be a real ambassador for the city. People can walk like a pedestrian in a virtual space. This tool can be enriched with references from merchants, companies or services, so that the viewer can click on a front door or storefront and switch either to their website or to the digital model of the interior of the building.
  • Risk management: The model, based on the reality of dimensions and shapes, becomes a support used for simulating floods or installing video surveillance cameras.
  • Urban logistics: The 3D model can be at the origin of the creation of a single control centre grouping several supervision missions (lighting, energy, roads, video surveillance, public buildings, parking, etc.). A citizen spotting a damaged pole, a blown bulb or something to remove on the road, can report it and locate it with precision. It can also be used for simulation of night lighting in public spaces.
  • Heritage documentation: Any deterioration of architectural heritage can be monitored by comparing the model over time. In the case of any damage, a 3D model forms an ideal documentation base for reconstruction work. Accurate measurements can be taken from the pre-existing 3D model to ensure that the reconstruction is carried out accurately and with the same materials

This project illustrates the global reach of Aerometrex’s 3D modelling service as well as the degree of 3D technical excellence that now exists in the company.