Viaduc de Millau

Model Origin and Accuracy 

The idea behind this project was to create the first printable 3D model of the Millau Viaduct integrated into its environment. To achieve this, the terrain was modeled using data from the Lidar HD program by IGN (France's National Institute of Geographic and Forest Information). This data source ensures remarkable accuracy, which explains the high level of detail in the relief. In contrast, the bridge's architecture has been intentionally simplified (piers, cables, deck thickness) to make it an object that is easy to produce with a 3D printer.

Recommended Print Settings 

This model was successfully printed on a Bambulab P1S with a 0.4mm nozzle. I used a 0.12mm layer height, which provides a good balance between detail and print time. A finer layer height (e.g., 0.08mm) will primarily enhance the rendering of the terrain. I advise against using a layer height that is too thick, as it could weaken the bridge deck.

Support Management 

The use of supports is necessary, mainly under the bridge deck. I achieved the best results with thin tree supports and 1 top interface layer. They are easier to remove and leave fewer marks on the final model.

Slicer and Material Tips 

The model shown was printed in ABS, which can cause some stringing. Printing in PLA or PETG will also yield excellent results, potentially with fewer difficulties. In your slicer, I recommend enabling the "Fill gaps" option (or its equivalent) to ensure good connection between pillars and the terrain.