Misalignment—Can 3D BIM Overrule Professional Setting-out According to Plane and Height?

Abstract

Building Information Modeling (BIM) is a superb initiative to improve planning, construction and operation of structures and hence to avoid multiple databases and design errors by cooperative and standardized construction planning using Industry Foundation Classes (IFC). This holds for structural engineering with the main dimension of buildings in height. In contrast, long infrastructure projects of civil engineering will encounter considerable problems as the Cartesian 3D coordinate system and a scale fixed to 1 associated with BIM must collide with the necessary considerations for map projection and height of our well-founded geodetic representation of the real world, resulting in misalignment. In particular, in tunneling, where we have to observe tightest tolerances, the problem currently is left to the site surveyor, which should be aware of the difficulty and how to cope with it. This investigation will expose the affair along theoretical derivations as well as practical examples and present the state-of-the-art of how the BIM community is facing the problem and tries to overcome it, once initiated by the author, who will also give his latest considerations and advices. The current practice of ignoring the incompatibility of the two approaches for infrastructure projects with considerable extension in length and trying to get along with subdividing into smaller sections or introducing covert interim co-ordinate systems for setting-out will not only corrupt the splendid general concept of BIM but the more place the surveyor in danger of sliding into a legal dispute.