High-Altitude Scan-to-BIM

ATFF provides Scan-to-BIM services using ReCap and Revit for a hospital renovation in the French Alps

The Project

The Aiguilles-Queyras Hospital Center is a 20,000-square meter facility in Aiguilles, France. Located in the French Alps, the facility has the highest altitude of any hospital in France. A renovation project is underway to accommodate more out-patient procedures, provide additional short-stay beds, and support upgraded security standards. Before starting the renovation, they needed accurate, existing-conditions information that reflected how the floors and walls had tilted over time. This was magnified due to the Alps’ mountainous and slowly collapsing geography. As a result, the hospital turned to ATFF, a firm that specializes in Reality Capture and Scan-to-BIM services. The hospital commissioned ATFF to capture the facility’s existing conditions and produce a highly-accurate 3D building model for design.

The challenge

“We faced two major challenges on this project,” says ATFF co-founder, Adrien Truwant. “We had to capture the existing conditions in January, which is a cold and snowy time in the Alps. Moreover, we had to accommodate the hospital’s natural activity, with patients and staff constantly moving around.” Additionally, documenting interiors and exteriors, including complicated roof lines, required terrestrial and drone capture.

The solution

“Our firm relies on Autodesk® ReCap™ Pro software because it allows us to use both laser scanning and photogrammetry, and then easily combine all this information into a single model,” explains ATFF’s other co-founder Florian Fauconnet. “For example, on this project, we used laser scanning to capture the inside of the hospital, and a camera mounted on a drone to capture the outside of the buildings.”

Scan-to-BIM

The firm had just over a week on site to complete their capture efforts. They used a DJI Inspire drone to capture the outside of the facility. A FARO Focus3D X 130 scanner on a tripod captured the hospital’s interiors. In order to avoid disruption to hospital operations, the team conducted scans during meal times, at night, and on weekends when possible. Surveying during off-peak hours limited digital artifacts, such as people in motion, that could obscure common data points. Additionally, this reduced Point-Cloud cleanup efforts.

ATFF technicians captured the roofs and facades in just one day. Over the next seven days, two technicians scanned the entire hospital interior from lobbies to operating rooms. They placed 3,500 targets in the building to identify matching data points between the various scans and optimize accuracy. In total, the technicians took 952 photos and 1200 scans.

ATFF then used ReCap to process, register, and clean up the data. The resulting Point Clouds could then be exported to Autodesk® Revit® or any other Autodesk design solution. ReCap automatically calculated the position of a scan based on targets, provided feedback against processed scans, and produced a Point Cloud.

With the Point Cloud generated, ATFF started working on the BIM part of the scan-to-BIM process. The team used the point clouds in Revit as a reference to develop a complete 3D model of the hospital.

Hardware: DJI Inspire drone and FARO Focus3D X 130
Software: ReCap and Revit
Scan time: eight days
Model time: 6 weeks
3,500 targets
952 photos
1200 scans

The result

“It took approximately six weeks to model the hospital,” says Fauconnet. “And without Reality Capture and ReCap, the total project would have taken months longer.” A traditional survey would mean more trips to the site for measurements, seriously delaying modeling efforts.

“We saved time and money using ReCap because the data was completely accurate, the point clouds were automatically assembled, and the software integrates perfectly with Revit—making the entire Scan-to-BIM process more efficient. This is especially important for a relatively small firm like ours and gives us an important competitive advantage.”
―Florian Fauconnet, Co-Founder, ATFF
“The ReCap Point Clouds helped us virtually move around each building and floor from our own office. We can remotely take measurements and revisit the site whenever necessary. In addition, we can use the point clouds to digitally collaborate with the hospital—helping them to better understand any issues surrounding the redesign of their facility.”
― Adrien Truwant, Co-Founder, ATFF