The principal difference between BIM and 2D CAD is that the latter describes a building by independent 2D views such as plans, sections and elevations, Editing one of these views requires that all other views must be checked and updated, an error-prone process that is one of the major causes of poor documentation. In addition, data in these 2D drawings are graphical entities only, such as lines, arcs and circles, in contrast to the intelligent contextual semantic of BIM models, where objects ore defined in terms of building elements and systems such as spaces, walls, beams and columns (CRC Construction Innovation,2007)