Advanced Geometric Modeling of Historical Rooms

To support the maintenance and restoration of Schönbrunn Palace in Vienna, Austria, as UNESCO World Heritage Site, an Integrated Facility and Asset Management System (IFAM) is designed. The IFAM will be based on a topologically and geometrically consistent data foundation. For that reason, an adequate method for data acquisition and modelling is essential. Conventional methods such as tachymetry or photogrammetry are restricted in their automation ability. Thus, they require a great amount of human interactivity during data capturing and modelling. Nevertheless, they enable a precise determination of linear structures at a certain level of generalization. But they are insufficient, considering data capturing and subsequent modelling of continuous surfaces. On the contrary, terrestrial laser scanning is well suited for acquisition of surface data. Unfortunately, most of the modelling methods currently used are not able to determine structure lines directly. In this article, a method for direct determination of such structures from terrestrial laser scanner point clouds is presented. Starting from these initial structures, a topologically consistent boundary representation is derived. The continuous surfaces between these boundaries are modelled by a triangulation. The closed surface model is textured using high resolution colour images. This workflow is shown as applied in Schönbrunn Palace. Finally, qualitative and quantitative capabilities of different laser scanners are discussed.