There are a number of consumer software packages which focus on simulation. The focus on accuracy puts them somewhere between games and "real" training simulations. Because they need to model the real world, they tend to contain a fair bit of virtual terrain functionality.
Flight Simulators in particular have historically tackled the world modelling problem in very closed, nonstandard ways, see Leveraging the Flight Simulation Field.
If you know of other simulation software that should be listed here, please let us know.