Virtual interactive 3D tour through the Vienna St. Stephen’s Cathedral
Live-Stream on 12 September 2020
Powered by RIEGL – Premium Partner of INTERGEO Digital 2020

Geomnibus Newsroom
September 02, 2020


The Ars Electronica Center’s Deep Space 8K enables a virtual interactive 3D tour of Vienna’s St. Stephen’s Cathedral based on a 21 billion laser dot RIEGL point cloud.

Learn more about this special project in the current press release of RIEGL

The live premiere of the virtual tour will take place during the 2020 Ars Electronica Festival on September 12, 2020 at 4:00 p.m. CEST and will be broadcast via Live Stream

The RIEGL VZ-400i laser scanner during data acquisition in and in front of St. Stephen’s Cathedral (Photos RIEGL)

The Translucent St. Stephen’s Cathedral, this year’s festival visit allows visitors to fly through the real-time rendered point cloud and explore fixed points. At these points, the high-resolution 360° images of the entire set of more than 21 billion laser points are superimposed, unfolding the full potential of the time-honored building. At this unique level of detail, the laser points, which are based on a RIEGL point cloud scan, correspond to a data volume of almost 400 gigabytes. This innovative approach offers an interactive journey through the “illuminated” building in stereoscopic 8K. A truly spectacular experience!

The scan data acquisition was carried out in the course of the already proven long-standing cooperation of RIEGL Laser Measurement Systems with the Dombauhütte St. Stephan. The goal of this cooperation is an exact recording and documentation of the building fabric of St. Stephen’s Cathedral by means of 3D laser scanning in order to create highly precise detailed plans from the point cloud data as well as to generate views and sections which can be used by the Dombauhütte for building analysis, damage documentation and simulation of historical building conditions.

Nikolaus Studnicka, RIEGL Business Division Manager Terrestrial Laser Scanning, explains: “In the typical workflow with the terrestrial scanner, one so-called panoramic scan after the other is taken. The operator carries the scanner, which is mounted on a tripod, about 10 meters further in a minute cycle and starts the next scan by pressing a button. In one full scanner rotation, an average of 22.5 million measurement points are recorded in 45 seconds. The spatial resolution at a distance of 10 meters is around 7 millimeters. The sophisticated RIEGL Waveform-LiDAR technology makes it possible to record hundreds of scans per day. For this scan project, five calibrated 45 megapixel photos were taken per scan position. The photo data enables the scan data to be colorized and thus provides a photo-realistic representation for further applications.”.

In total, more than 1000 scan positions were captured with a RIEGL VZ-400i laser scanner – in the church interior, in the catacombs, in the attic and at St. Stephen’s Square. The scans were already assembled in the scanner and then adjusted to an accuracy of 6 millimeters to 50 precisely calibrated control points by means of so-called block adjustment.

The entire volume of scan and image data of slightly more than one terabyte was generated in only four measurement days in the years 2018/2019 with the laser scanner and in two measurement days with a total station.

When the staff of the Immersify project became aware of this gigantic resource, they wanted to use this potential for a virtual journey through the Vienna landmark in stereoscopic 8K.

The Translucent St. Stephen’s Cathedral conveys the feeling of experiencing real-time and interactive content in the highest quality – a rendering that is actually not possible in real time with today’s technology standards. Two types of content were combined to achieve this: A “High-Resolution” point cloud, which was pre-rendered by ScanLab Projects from different perspectives into 360° images, and a “Low-Resolution” point cloud, which is rendered in real-time. This extraordinary view of Vienna’s St. Stephen’s Cathedral with several layers of transparency will now be on display in stereo in Ars Electronica’s Deep Space 8K.

The live premiere of the virtual journey will take place during the Ars Electronica Festival 2020 on September 12, 2020 at 4:00 p.m. CEST and will be broadcast via live stream .

Festival visitors can also take part in a short demonstration at Deep Space 8K on each day of the festival (September 9 through September 13, 2020).

The unique insights into the levels of St. Stephen’s Cathedral were created as part of the research and development project Immersify, which was funded by the EU Horizon 2020 program and dedicated to the development of the next generation of immersive media. Over a period of three years, the project partners-including Ars Electronica Futurelab (Austria)-used various techniques to develop content for highly immersive environments and tools for processing the data produced in the process.

With a truly impressive result that’s something to be proud of!

Project description and video on:

The translucent St. Stephen’s Cathedral

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