In the course of the shell inspection of the new company headquarters of Louis Opländer Heizungs- und Klima GmbH, digital tools were included in the inspection. Stephan Embers and Patrick Herbers were interviewed about this. Both are researching the use of augmented reality in construction, and Patrick in particular also on BIM-based interior location.

Which applications were tested for the digital shell inspection and how did they work in each case?
Stephan: We tested the apps GAMMA AR and Dalux Field. With both applications, the positioning works manually as far as possible. With GAMMA AR, you first anchor yourself by means of the plane localization and then use an arrow to select in which direction the model should align itself. Then the image is overlaid with the model. It gets difficult when you move or swivel the tablet a bit to the left and right, then the system loses the exact orientation relatively quickly.
The situation is similar with Dalux Field. A 2D plan is used for manual localization, the viewing direction is entered, and then the model has to be adjusted to reality by hand. For example, a model support is then manually adjusted to the actual support so that the rest of the model matches it. Again, it is problematic that an excess of movement distorts the overlay very much. On a positive note, however, Dalux allows notes and annotations to be made in the IFC model in real time. This has the advantage that no more data is lost, everyone has the same level of knowledge, everything is legible and people in the office can directly see what has been noted. This can make work much easier.
 

So what is the general problem with BIM-based interior location?
Patrick: The issue basically breaks down into three problems. One is the initial location: When I turn on the device or start the app - where am I? Optimally, that should work automatically. The second problem is tracking - where am I located when I move around the room or the automated tracking of movement in the room. The last big problem is hardware. When cell phones or tablets are used, there are usually too few cameras or sensors in use and the polling speed is too slow, making orientation difficult. In addition, the "dead reckoning effect" complicates the results. This involves incorrect measurements, e.g. of measured distances, which build on each other - these inaccuracies accumulate over time and the result is thus completely falsified. One solution can be the Hololens, for example, as these enable a wider field of view due to the many different cameras around the helmet and facilitate tracking.
Basically, it is also important that the technical equipment is not too old. Not all apps are usable on all Android/ IOS versions. Sometimes built-in scanners are also missing on Apple devices, for example, as these are only available on newer ones. This is another difficulty.
 

What would be the ideal and best working version of the digital shell inspection?
Patrick: Ideally, a combination of devices would be used. If we stay with shell inspection, tablet-based viewers on which AR applications work are of course super. They very clearly illustrate to the various professions present the extent to which practice and theory match. In addition, depending on the application, data can be stored directly and centrally in the BIM model without any detours. However, a system like the Hololens in combination with a measuring laser scanner are indispensable for a really functioning digital acceptance due to the required accuracy of the data.
Stephan: Of course, you have to consider that such equipment can be relatively expensive. Furthermore, all systems must be user-friendly, so that no above-average training or implementation is required. There are many possibilities, but at the moment there is still the question of implementation. A uniform documentation in the 3D model can certainly be a good start.

Stephan Embers, M. Sc. (more...)

Patrick Herbers, M. Sc. (more...)