In theory, all the technological prerequisites for the paperless construction site are in place, but in practice most construction work today is still carried out based on 2D plans. These static construction drawings have significant disadvantages: Locally stored plans without automated versioning mean that crafts do not have complete information and updates are often not considered in time. This can easily lead to errors. 

As part of a design-build seminar, students at Leibniz Universität Hannover have been researching how buildings can not only be planned but also constructed through the interaction of various possibilities of digital technologies: for example, by using augmented reality and without the use of classic construction drawings. What are the findings? What are the upcoming research approaches?

From digital planning to digital implementation

Xella aims to close the gap between digital planning and analog implementation on the construction site and has been engaged in the use of augmented reality on the construction site for many years. For example, the company uses the Hololens2 in the Trimble construction site version to visualize digital planning and to perform a quality check on the construction site as part of a target/actual comparison. This procedure has already been used for several years in the Netherlands, Germany, and Poland, among others.

The paperless construction site project

The students at the Faculty of Architecture and Landscape Sciences led by Prof. Mirco Becker are now purposefully going one step further: the project "Paperless Construction Site" proposes a new approach in the construction industry, using only the computer or smartphones, tablets, and Head-Mounted-Displays via augmented reality for detailed and extended information during the construction process. The research objective was to investigate the benefits and impact of augmented reality technology on the architectural design and construction process.

Xella supplies expertise and Ytong plan blocks 

Xella supported this research project by providing practical expertise and by delivering Ytong blocks P2. In the highly simplified project compared to the real situation on the construction site, a stone sculpture was planned based on a real building using an algorithm created with the Software Rhinoceros 3D and the visual scripting environment Grasshopper. Using the digital model, the first layer Ytong blocks were not only initially placed on the surface according to plan but were also subsequently assembled successively. The arrangement of the blocks was done by the students themselves with the help of smartphones and three virtual reality head-mounted displays. The QR codes tagged on some of the blocks served as anchors for their real-world placement. 

Once the sculpture was completed, an augmented reality environment was created using the Unity platform for smartphones, which allowed visitors to the site to visit a virtual exhibition of the concepts explored in the project: Panels with images, texts and videos were displayed here. In addition, a hologram was installed on the existing demonstrator to visualize the potential for building extensions.

Photos: Leibniz Universität Hannover, Fakultät für Architektur und Landschaft

Augmented reality transfers digital designs into practice

The experiment ultimately showed that the use of augmented reality in the construction phase is possible even without classic design plans in 2D. However, with the current state of smartphone self-referencing technology, it was shown that tolerances of up to 3 cm must be planned when positioning the blocks - a challenge that could be overcome in the future, for example, by integrating a total station from the field of surveying technology.

What is the current state of research?

Prof. Mirco Becker from Leibniz University in Hanover is certain: "In the future of construction, autonomous machines and humans will work together on the construction site. Machines don't need plans; they get their instructions from the routines of intelligent 3D models. The same is true for people who receive their instructions from the same routines on tablets or head-mounted displays. Human capability is only used where it surpasses current machine perception or where humans act as a responsible legal body." 

Andreas Radischewski, Digital Building Solution and Transformation Manager, who accompanied the project on the Xella Group side, also says, "The trial shows that it will be possible to do without classic plans with the help of augmented reality."

However, he still sees some obstacles that need to be overcome before the process can be used so currently in series production. The high cost of augmented reality goggles is the main factor here: in construction site execution, he says, this is currently around 4,800 euros. In addition, a strong Internet connection must be always available at the construction site since the underlying data is in the cloud. 

Professor Becker also makes it clear that the research project represents a strong simplification of the actual situation on the construction site: For example, practical circumstances such as the solar radiation of today's hardware can also cause problems with the localization of the virtual model.

When will 2D plans be history on the construction site?

It is not yet possible to say how long it will be before the use of augmented reality solutions becomes standard on construction sites. "It's hard to set a date," says Prof. Mirco Becker, " but we believe that 2D plans will soon disappear from the site, as they are already becoming obsolete in the design process since we work in 3D models. We don't think of space and architectural form in plans." 

However, he adds that the main benefit of augmented reality at this point is already clear: "With augmented reality, implementation on the construction site is much less abstract because you can visually experience and move around the design on site at a real scale. This makes it possible to understand how the new proposals will interact with the existing site. With the proliferation of smartphones and tablets, the development of commercially available AR glasses, and new, easy-to-use software integrated into our CAD environments, more and more people will use this technology at some stage of the design and construction process," Becker said.

"Five to ten years" estimates Andreas Radischewski, against the backdrop of current challenges, it will take until 2D plans are history. This is an exciting topic that Xella will continue to follow closely. In the coming years, a lot will happen here in terms of productivity and efficiency on the construction site. We will continue to keep you up to date.