CAAD futures Digital Proceedings 1991 549 36. The Reconstruction of the Past: the Application of New Techniques for Visualisation and Research in Architectural History Patricia Alkhoven Department of Architectural History University of Utrecht 3512 HD Utrecht, The Netherlands This paper focusses on the visualisation of historical architecture. The application of new Computer-Aided-Architectural-Design techniques for visualisation on micro computers provides a technique for reconstructing and analysing architectural objects from the past. The pilot project describes a case study in which the historical transformation of a town will be analysed by using three-dimensional CAD models in combination with bitmap textures. The transformation of the historic town will be visualised in a space-time computer model in which bitmap textures enable us to display complex and relatively large architectural objects in detail. This three-dimensional descriptive model allows us to survey and analyse the history of architecture in its reconstructed context. It also provides a medium for researching the dynamics of urban management, since new combinations and arrangements with the individual architectural objects can be created. In this way, a new synthesis of the graphic material can reveal typologies and architectural ordering systems of a town. The historical project Ever since Aldo Rossi's "The Architecture of the City", interest of architects and historians in the comprehensive analysis of the city has assumed enormous proportions (Rossi 1984). In search of design solutions, the history of the place (locus) and context is once more being taken into account. A successful urban development design presupposes a thorough knowledge of the city, its elements, its history and its dynamics. The city is to be conceived of as a collection of architectural 'facts' which can only be understood through an examination of the historical process. The complex analysis of the dynamics of urban processes demands careful examination of the elements which form the city and the forces that work upon it. The elements that constitute the city can be separated in permanent and semi-permanent phenomena. In general, public monuments (church, town hall, etc.) are more or less permanent structures while houses and shops are considered semi-permanent elements, since their appearance is highly dependent on fashions in design. In the same way we could view the houses as relatively permanent structures and their facades which are renovated every twenty or thirty years as semi-permanent. The facades and interiors of shops nowadays even change every three to five years.