How GeoZICHT uses Twinsity to enable virtual bridge inspections

posted by Sabrina Siebert on September 14th, 2020

Inspecting a railway bridge using drones-that was the mission for the company GeoZICHT from Utrecht.

GeoZICHT is specialized in the generation of complex geodata. They offer various services with drones, from high quality point clouds, 360 degree aerial photographs to elevation models. The company's drones are also perfectly suited for operations in dangerous and hard-to-reach locations for industrial and infrastructure work.

For therailway project, their client decided to take up the bridge by using drones instead of a manned inspection. Due to the detailed photographs taken by the drone, 2500 images of the bridge were available at the end. But it is difficult to carry out an exact inspection only based on these pictures. This is caused by the fact that the bridge was not available as a whole. Working through the different photos in detail would be an option, but not very efficient. Therefore GeoZICHT decided to read their data into photogrammetry software to generate a 3D model. This was later imported into Twinsity-the visual resolution of the textured model matched the images of the drone exactly.

The integration of Twinsity into existing workflows was uncomplicated thanks to the ease-of-use of the software. The realistic and exact visualization of the bridge as a 3D model enabled optimal handling of the generated drone images. Inspecting interesting places was greatly simplified by the intuitive first-person mode, since cracks and other irregularities are directly visible thanks to the extremely high resolution. In addition, the software's visualization made it possible to easily inspect areas that would have been hardly accessible for a manned team. The various features of Twinsity made it a simple matter to work directly in and on the 3D model.

“Twinsity proved to be the best tool for this job –as it’s able to render the full texture resolution in a smooth 3D environment, with the ability to add annotations directly onto the mesh and using the high fidelity of the model to accurately measure small deformations of the concrete.”

Jasper Mink, GeoZICHT

This digital and new way of inspection allowed a significant saving of time. On the one hand because of the easy and uncomplicated training and use of the software. On the other hand because the bridge as a complete entity was displayed on the computer and there was no need to work through individual photos. At this point, the use of the various features, such as annotations or measurements, was very helpful in order to proceed efficiently and innovatively with the inspection