Study from Building Density to Building 3D Density

Building spatial density is presented to describe the urban fabric on the basis of the research on the urban fabric from three dimensions, which is as form of city characteristics. Evaluation system for the building 3D density is founded according to the theory of "figure-ground relation" and the algorithm for building density and floor-area ratio (FAR). This evaluation system puts forward a series of quantitative algorithms, together with a qualitative approach to 3D-fabric-based schema, to rationally describe the density of the buildings in certain district and the changes of spatial structure or the trends of spatial sprawl. The agreement between the data statistics and analysis on certain samples shows the applicability of the system and the accuracy of the computational methods. This system can help to estimation on land-use, as well as to urban design.