What is IFC?

buildingSMART defines specifications for expressing all architectural objects (elements such as doors, windows, walls). These specifications are called IFC (Industry Foundation Classes). Project/model data structure used in the application are also produced.

These “Classes” defined by buildingSMART are notated as IFC.

I (Industry)
  :Construction Industry(Industry)
F (Foundation)
  :Shared project/model foundations(Foundation)
C (Classes)
  :Classes agreed upon to structure a universal language(Classes)


A “door” defined in IFC is not just a simple collection of lines to display a “door”. It has attributes which allow the element to be recognized as a “door”.
In a project, many different types of “doors” are used. In one “door” the width is 900mm, and another “door” width would be 1200mm, each of these are recognized as a “door” and have properties universal to “doors” defined by IFC specifications. A “class” is a definition of a universal property, where each entity is defined as a “object”.

An “object” in IFC can be shared between different disciplines of the construction industry. A “door” designed by an architect can be treated as the same “door” by consultants of other disciplines. In this way, quantity valuations, MEP design, construction, and facilities management can be made more productive through sharing.

IFC allows data interoperability between software in the construction industry. This IFC specification document defines class libraries for object-oriented programming aimed at software/application developers. A door object created in one application can be exchanged with other IFC compliant applications. Other applications will automatically recognize the door object.
In this way, the properties of the door object can be expressed in an object-oriented way as the following.

“I am a door, recognizing what type of door, made from what material, finished in what way, opened which way, in what geometry, and where the door top frame, side frame, hinge and threshold is.”

Other applications understand these properties, and the object can be supplemented with information defined by IFC specifications by buildingSMART.

Further, electronic information data (such as drawings, reports and specifications) can be shared through IFC compliant applications. This means the guaranteed unification and validity of the data. The shared data continues to develop after the design stage to the construction stage. The information created by the designer becomes an intelligent electronic format and can be used in construction and facilities management and maintenance through IFC compliant software.