Building model

A building model is either a physical (real) or virtual (computer) model of a building. Very often, the physical model is smaller than the original (scale model). 
There are three basic types of building models: architectural, structural and mathematical (virtual).
Architectural building model.
An architectural model is a type of a physical model of a structure to study an architectural design or to share design ideas to clients, committees, and the general public. Architectural models are a tool which may be used for show, presentation, fundraising, getting permits, and sale purposes. Such models are a good tool for three-dimensional understanding of a design, used by architects, interior designers and exhibit designers.
Structural building model.
Engineers who need scale models to test the likely performance of a design at an early stage of development without paying for a full-sized prototype.
Virtual building model.
Virtual model is a digital model of the object (typically greatly simplified) that can be used in a computer simulation or virtual reality.
The most common examples of virtual models are those created in 3D for the purpose of "visualisation" - seeing how the structure looks before it is built. The field of architecture has greatly popularized the use of virtual models to animate fly-throughs of yet-to-be-built buildings.