Geometrical and Topological Modelling of Buildings

As buildings are mostly parameterised by 3D point coordinates in CAD systems, the acquisition of geometrical data for buildings can be a very expensive task. Even for not very complex buildings this approach results in large data sets of redundant data. As a consequence, geometry is often disregarded for facility management systems or will be added just as descriptive information. The authors show that by the parameterization of surfaces instead of 3D point coordinates, the number of parameters and therefore the data set will be reduced considerably. The presented approach is based on parameters of surfaces and a strict modelling of the 3D topology. In addition to an appropriate building data model the improvement of the data processing procedure rather than the data acquisition methods applied on site have to be focussed and solved. Based on this approach, proposals for an economic solution of the task of geometrical data acquisition of buildings can be derived. For ordinary buildings, robust and simple to handle measurement tools can be applied, like measurement tapes or hand hold laser distance measurement instruments. In addition, the data model provides the frame for an integration of different types o