Case study
A traditional mountain hut goes digital
3D laser scanning enables quick, precise data capture and the creation of accurate 2D models and 3D digital twins. Surveyors like Hilmar Schroeder have leveraged this technology to expand their services. Schroeder created a detailed 3D virtual replica of an Alpine hut in Austria to support renovation planning and offer virtual tours.
Beate Wesenigk
Central Europe Marketing Manager for Leica Geosystems, based in Germany.
Susanne Boettcher
External top-management assistant who offers support in communication, PR and events as well as in office planning and organisation.
Hilmar Schroeder, a surveying contractor based in Wilnsdorf in Siegerland, Germany, was commissioned by the German Alpine Association (DAV) to survey the Siegerlandhuette (Siegerland mountain hut) in the Stubai Alps and create a digital 3D twin for virtual tours and renovation planning — a project that is particularly close to his heart as a hobby alpinist and passionate surveyor.
THE SURVEYING TEAM
With his dedicated team of four, Schroeder serves clients from a variety of sectors, including industry, shipbuilding, heritage conservation and real estate. The data that he collects for his customers is subject to strict confidentiality. He is always grateful when he receives data from projects that allow him to demonstrate the diverse applications of 3D laser scanning, laser tracking and unmanned aerial vehicles (UAV) to customers and prospects. To obtain the most accurate data for his projects, Schroeder uses various laser scanners from Leica Geosystems, part of Hexagon. Immediately enthusiastic about the project, the German Leica Geosystems team provided additional equipment. After all, a transalpine project like this — a German surveyor capturing the Austrian Alps with Swiss precision technology — is not an everyday occurrence.
A DIGITAL TWIN
A digital twin is a complete and detailed 3D digital image of real-life objects: houses, bridges, roads, train stations, tunnels, factories, cars, aeroplanes and much more. Today, these digital twins are typically created during the planning and construction phases. For an almost 100-year-old mountain hut not even paper plans exist that could be digitised. The DAV is planning renovation work at the Siegerlandhuette in the coming years. Measuring with traditional tools, such as tape measures and folding rules, to redraw the hut in a CAD programme would be laborious and time-consuming. Modern 3D laser scanning technologies offer a quicker solution. With a 3D twin, the DAV has a millimetre-precise model for planning conversions, extensions and renovations. The DAV can also offer a virtual tour of the hut, which many hikers will appreciate. Should the gut ever suffer damages, for example, because of a fire, the model can serve as a base for an authentic restoration.
THE JOURNEY TO THE SIEGERLANDHUETTE
The Siegerlandhuette, an impressive hut run by the Siegerland section of the DAV, is situated at an altitude of 2,710 metres east of Soelden in the Oetztal valley, surrounded by the majestic 3,000-metre peaks of the Stubai Alps. It was built in the summers of 1928-29 and is modelled on a nearby Renaissance castle. The hut holds a special allure for many people from Siegerland. In fact, a staggering 75% of the hut’s visitors come from that region. Schroeder and his team have also been able to sign the guest book. On a sunny Sunday afternoon at the end of June 2023, Schroeder and three of his team members set off from Wilnsdorf to Soelden. The team began the ascent to the Siegerlandhuette on Monday morning. Their luggage, including all the measuring instruments, weighed around 12 kilogrammes. After a four-hour climb spanning more than eight kilometres and an elevation gain of 750 metres, the team made it to the hut. Pausing only briefly to recharge, they promptly commenced their measurements.
With the help of the RTC360, 77 viewpoints were captured, corresponding to about half of the hut. By the evening, all the bedrooms, the stairwell, the attic, the kitchen and the host’s apartment had been captured.
The following day, both the BLK2GO and the drone were deployed. The drone’s operations were temporarily paused for safety reasons as a helicopter landed at 10 a.m. to deliver and install the photovoltaic system for the hut’s roof. Still, the team successfully captured the entirety of the Siegerlandhuette by early afternoon. Anticipating a chilly night ahead at the uninsulated hut, the team spontaneously decided to descent a day earlier than planned. “Overnight stays in huts are not everyone’s cup of tea. Even in summer, temperatures up here are around freezing point at night,” Schroeder winkingly explains.
WORK IN THE OFFICE
Back at home, the data collected was processed. First, all the point clouds generated by the scanners and the UAV flight were precisely aligned with each other.
The data from the scanners were already pre-aligned thanks to the camera eyes in the RTC360, the LiDAR dome on the BLK2GO and the Leica Cyclone FIELD 360 field software.
All point clouds were linked together in Leica Cyclone REGISTER 360 PLUS, which also removes noise, performs fast classification, anonymises data and much more. This workflow prepared the data for publication in a range of formats — such as industry- and Leica Geosystems standard — for analysis or transfer to other software systems.
Using Leica CloudWorx, Schroeder’s team generated floor plans, cross-sections and multiple views to deliver accurate plans of the Siegerlandhuette. They developed an exact, textured 3D model of the hut and created a virtual tour with Leica Cyclone 3DR. This digital twin of the hut was also used to simulate plans for the remodelling. This allows the planners and the DAV to see what the renovated Siegerlandhuette will look like and assess the spatial feasibility of proposed changes.
The precise and complete data from around 10 hours of surveying work on site was processed in just a few days using intuitive software modules to produce results that inspire the DAV.
