In simple terms, and as it pertains to dbaArchitects, BIM is the virtual three-dimensional representation of a building. The building is modeled through all phases of design and documentation. Two-dimensional construction documents are done in the same file by augmenting the model with annotation. Since the building is modeled, it’s easy to view and work in three dimensions, as well as present the project in various stages of its design. All of dbaArchitects projects are done using Graphisoft’s ArchiCAD, which is the first software to make extensive use of BIM.
The earliest schematic design is done by sketching on paper. The sketches are input into the computer for firming up the design and for visualization. Sketches are typically done all through the design process in conjunction with modeling the building.
Construction documents that are produced from a BIM file are less likely to contain mistakes in the building because all elements of the model are simply being viewed from different angles or in different combinations to show/hide the relevant information.
For a detailed description of all that BIM entails, see Wikipedia’s entry.