Because reliable models of most of the buildings in the city do not exist, SOM created its model using a combination of aerial photographs, public information, archival drawings, and, where needed, estimation. The accuracy and detail of the digital model for each building is tracked, and models are switched out for more detailed versions where necessary.
The first thing that had to be modeled was the topography, which in San Francisco is a varied thing. Discrete orthogonal street and intersection data was overlaid onto a 3D model built from the available contour lines of the city to create the 3D street surface.
The model allowed the architects to create a series of visualizations that can help them consider the limitations on certain projects. This diagram shows the city's current height limits, and highlights both the number of buildings built before current limits were passed and the potential for other sites to increase vertical density.
The embedded metadata includes zoning and building typology information, which can be used by the firm or the planning department to generate models such as this one, which shades buildings according to their recorded land use.
San Francisco's vulnerability to seismic events impacts structural needs and planning. This map of the known liquefaction zones (shaded in red) highlights the city's most vulnerable areas and can be used to determine best practices for new structural projects.
Any city with tall buildings suffers from wind tunnels. This diagram shows high wind velocity over the financial district and can be refined to show wind speeds at specific sites and intersections. This can help influence the construction of new buildings and public spaces.