## 2 Industry Foundation Classes, a Brief Overview  
IFC is an open format of data exchange that is well established worldwide in the field of BIM. The IFC file format (\".ifc\") enables the exchange of data not only associated with the geometrical properties of the components, such as walls, beams, and columns, but also heterogenous attributes, i.e., the mechanical and physical properties, costs, construction work time, and much more. The IFC format is designed for making an object-oriented data model of a civil engineering construction truly interoperable between different software packages. The IFC architecture is based on the structure of the STEP standard [15] and has been continuously developed by buildingSMART since the first data model standard release, IFC 1.0, dating back to 1996. Over the years, every new proposed release--the current version is labelled as IFC 4.1--introduced new concepts to the IFC specification to catch more exchange-use cases and to improve existing definitions based on the lessons learnt from the implementation and usage [16]. The assessment of the IFC 2x release, published in 2000, confirms the described approach. More recently, IFC 2x3 [17], released in 2006, has been widely promoted by all software houses, often supported by the certification of conformity from buildingSMART [18]. IFC 4 is the most recent release, issued in 2013 (ISO 16739:2013) and updated to IFC 4 ADD2 TC1 (ISO 16739-1:2018). The latest version, IFC 4.1 (2018), is recommended by buildingSMART for all current developments. A very recent, but still under development, release is IFC 4.3, which extends the IFC schema to the domains of railways, roads, ports, and waterways [19]. The improvements to IFC 4 are related to a new documentation format, extensions of IFC in structural areas, and enhancements of geometry description [19]. Generally speaking, the IFC 4 format overcomes the limits of the past formats in data-exchange between different platforms [20]. The higher the complexity of the work to be accomplished, the greater the diversification of the professional skills involved in the process, and consequently, the greater the quantity of information to be exchanged. Often, most of this information is redundant or even useless for specific phases of the design or, in general, for the building project workflow [21]. This results in a lack of efficiency in the work phases and difficulty managing the types of exchanged information. However, this exchange must be supported by the different software packages involved in the process during the lifecycle of a structure; therefore, the correct interpretation of the exchanged information takes a fundamental role. This concept is at the base of the model view definition (MVD), a subset of the IFC scheme, which permits the exchange of information in different areas of the design and construction process of a building and defines the dataset to be transferred depending on the particular use. Each IFC version is associated with a series of official buildingSMART MVDs. The most common model view is the Coordination View 2.0 [22], related to IFC 2x3, which can deal with both architectural information and structural analysis data. The CV 2.0 is a wide schema, covering the data related to both the CAD and CAE processes. The structural analysis view schema, also labelled the Structural Analysis View (SAV) [23], is an MVD belonging to IFC 2x3 TC1 [24]. The purpose of the SAV is to integrate information related to structural engineering, such as loads and load conditions, boundary conditions, constraints, materials, and connections between the elements. The standard format IFC 2x3 implements the structural analysis schema, with all the basic information to effectively operate without relevant data dispersion, except for the data related to the dynamics of the structures not yet implemented in that standard. IFC 4 extended the support for geometries and parametric data, building services and structural domains, and GIS mapping.