The aim of this project is to develop a software system for generating complex digital models of existing buildings and structures, i.e. in the broadest sense a computer-supported surveying and management system for existing buildings. The built environment is registered by surveying a series of geometrical and building relevant information broken down into different levels of abstraction. The recorded data consists of a variety of geometric, multimedia and verbal - less structured - pieces of information. The starting point for developing such a system is both an analysis and reworking of the methods used in architectural surveying, and the evaluation and use of current techniques and tools in the field of computer applications.