Realism vs. Reality in Digital Reconstruction of Cities

The digital reconstruction of existing cities using virtual reality techniques is being increasingly used. For consultants, municipalities and planning departments these models provide decision support through visual simulations (El Araby, 2001). For academia they provide a new tool for teaching students urban design and planning (Okeil, 2001). For authorities they provide a tool for promoting the city on the world wide web trying to attract more businesses and tourists to it. The built environment is very rich in detail. It does not only consist of open spaces surrounded by abstract buildings but it also includes many smaller objects such as street furniture, traffic signs, street lights, different types of vegetation and shop signs for example. All surfaces in the built environment have unique properties describing color, texture and opacity. The built environmentis dynamic and our perception is affected by factors such as pedestrian movement, traffic, environmental factors such as wind, noise and shadows. The built environment is also shaped by the accumulation of changes caused by many influences through time. All these factors make the reconstruction of the built environment a very complex task. This paper tries to answer the question: how realistic the reconstructed models of urban areas can be. It sees “Realism” as a variable floating between three types of realties. The reality of the physical environment which we are trying to represent. The reality of the digital environment which will host the digitally reconstructed city. And the reality of the working environment which deals with the problem of limitation of resources needed to digitally reconstruct the city. A case study of building a 3D computer model of an urban area in the United Arab Emirates demonstrates that new time-saving techniques for data acquisition can enhance realism by meetingbudget limitations and time limitations