How Does BIM Work? Building Information Modeling Foundations

Every profession and occupation has a language that is its own… physicians have anatomical, drug and procedural language; lawyers have legalese. Architects speak the language of aesthetics, building materials and budgets. How then, as an Architect, does a person interface with a computer -especially when you get down to it – the computer only ultimately understands 1’s and 0’s.

BIM Software, such as Revit, speaks the construction oriented language of architects… that of doors, windows, walls and assemblies, and then does something really incredible. It keeps track of each of those entities in what is called a ‘database’ – essentially, a way for computer programs to categorize and organize information. Keeping watch over these various pieces like an unseen referee, the software insures that each element is in the place that it is put relative to the others. And, when asked to do so, can find conflicts based on the rules of reality.

How does all of this happen?

BIM works through the creation of a database which is IFC compatible. IFC refers to Industry Foundation Class, and is a non-proprietary system of referencing building and construction industry information. Since this system is neutral and not controlled by any vendor or set of vendors, latitude and flexibility enable a platform that is based on IFC to be consistent throughout a range of software and various companies. IFC is important because it helps maintain similarity between building models and software programs. Since the author has had experience primarily with REVIT from Autodesk, he will be explaining the capabilities of that software as the articles continue.

The Building Information Model used in Revit is managed by XML, which is also known as Extensible Markup Language… a computer scripting language that can be understood by both people and computers. It is appropriate due to its use and application in a wide variety of representative data structures, as would be seen in internet applications.

Due to a User Interface designed specifically for Architects and those who design buildings, the building model is created ‘behind the scenes’ while the designer is using and defining standard elements of construction, such as walls, windows and doors.

Since a database element is created each time a building element is used, lists of the building elements are very rapidly created… as easily as or even more easily than the drawings are created. A variety of attributes of the objects are also stored, and there is even the possibility of defining a number of attributes for each object.

The designer enters the location and type and quantity of pieces in the proper places and the software shows the relationship between these pieces from various views and a variety of points of emphasis. This 3D information is able to then be ‘transcribed’ into 2D information so that drawings may be printed for approval and construction.

For the client, this is important because it means that his or her drawings will be more accurate. For the Architect, his realistic liability is decreased and his confidence is increased because his drawings are more accurate. For both, if the Architect is directed to make a change by the client, and there are problems, the problems will become immediately evident to him. For the consultants, since they are working with a 3D model, they are immediately able to understand the implications of the variety of design decisions that they will need to make and readily assess their work to see if there are conflicts with the architecture.

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