Structural models for buildings having sub-grade elements (basements, private drain connections, fresh water lines, septic sewer services, electical line feeds, etc.) would create for greater realism and analysis.
For example, a house with a basement (with complete footing details, stepped foundations on hills for "walk-out-basements, etc,) can be then placed in a more realistic manner for sloping ground.
Groundwater map data (subterranean), soil/rock geotechnical data, seismic zone data, climate data (storm water, wind veloctiy, snow load - all from the AutoDesk climate server used in Revit) etc. are other examples of commonly available data sets that can be used to provide a more realistic model, not only to "look" at, but also to provide tools from which more detailed and required analysis by Civil Engineers is required by law.
