What is IFC?

Industry Foundation Classes (IFC) is a standardized, digital description of the built environment.

IFC provides a structured and consistent manner to describe both the physical (e.g. slabs, columns) and abstract concepts (e.g. relationships) of buildings and civil structures, and this facilitates exchange of information across domains and use cases.

IFC is developed by buildingSMART International, and is also published as an international open standard (ISO 16739).


Why use IFC?

Being open and neutral, the IFC standard is vendor agnostic, and can be supported across various software platforms, interfaces and applications. The standard acts as a common language to enhance information exchange and collaboration.
IFC also serves as data preservation against obsolescence of software versions, and with information being captured in a structured manner, it facilitates analysis and extraction of information.


Difference between IFC2x3 and IFC4

The development on IFC started in the mid 1990s, and the first version was released in 1997.

buildingSMART International continued to work on developing the standard, with IFC2x3 established in 2006, and the newer and more comprehensive IFC4 established in 2013. These are the more commonly used versions in the industry. Find out more about IFC version releases here.

Difference between IFC Entities, Type Objects, Attributes, Property Sets and Properties

The IFC schema holds the structure of how building related information can be stored. IFC has already defined data structures (e.g. entities and attributes) to hold information about the building and its elements (such as walls, columns, doors, etc)

A few useful data structures to take note of:

IFC Entities
  • An IFC entity can be used to describe a physical element (such as IfcDoor for a door, IfcWall for a Wall), or a conceptual idea (such as IfcZone to indicate a group of spaces).
IFC Type Objects
  • IFC has further defined entities with its sub-types, so that commonly shared information could be applied to all occurences of this type. For example, users can tap on the already defined (predefined) list of wall types (e.g., PARAPET, MOVABLE, etc.) in IfcWallType to indicate the type of wall used in a building.
IFC Attributes
  • The attributes data structure in IFC helps to hold information regarding the characteristics of entities. Attributes can also be inherited from the parent entities in the IFC entity hierarchy.
  • For example, the attributes "GlobalID" and "OwnerHistory" is defined in IfcRoot (the base class that all entity definitions are based on), and all entities inherit these properties.
IFC Property sets and properties
  • IFC has also defined sets (or groups) of properties that can be used to further describe the entity, and usually starts with "Pset_" naming convention.
  • For example, to describe the wall, IFC has defined 2 groups of properties: Pset_WallCommon (with common properties such as AcousticRating, FireRating, etc.) and Pset_ReinforcementBarPitchOfWall (with common properties such as BarAllocationType, VerticalBarPitch, etc.). Users can use the properties that they need to describe the element of interest.

Other points to note:
  • Besides these IFC predefined data structures that can be used to contain information of the building, IFC also offers the flexibility to add on customized or user defined properties and type objects, to cater to varied needs.


How to export to IFC in BIM authoring tools

Most native BIM authoring tools are IFC certified. To help you familiarize with exporting to IFC on a few of the major BIM authoring tools, here are some available resources that you can refer to.

Autodesk Revit
Bentley OpenBuildings
  • Online help on exporting to IFC in OpenBuildings
  • Recording of the IFC Webinar, which includes demonstrations on features supporting IFC
Graphisoft Archicad
  • Online help on exporting to IFC in Archicad
  • Information on working with IFC in Archicad
  • Recording of the IFC Webinar, which includes demonstrations on features supporting IFC
Trimble Tekla
  • Online help on exporting to IFC in Tekla
  • Recording of the IFC Webinar, which includes demonstrations on features supporting IFC
More about BIM Software IFC Certification

buildingSMART International certifies software that supports the IFC schema, to give users and customers the assurance that the software and solutions is compatible and supports the IFC versions they need.

BIM software companies are also keen to have their applications and solutions certified, to enable their AEC customers and practitioners to work with a wide range of tools and successfully collaborate with different project stakeholders.

The list of certified software can be found here.


Missing Information When Exporting to IFC


It is important to keep in mind that the intent for IFC is to facilitate exchange of information. IFC models are generated from native BIM models. Therefore, the information of interest must first be created in the native BIM models before it can be exported and found in the IFC model.

If there were missing information or unintentional errors in the original native BIM model, the IFC model that was exported would have the missing information or errors too.

You may want to refer to resources above to troubleshoot your IFC export issues.

IFC Format for CORENET X Submissions


With the development of CORENET X and the intended Automated Model Checking capabilities, a common format is required to validate the submissions and allow reviews across agencies on the Collaboration Platform.

IFC is proposed as the base for the common representation. With information being stored in a consistent data structure, the models can be used for future analysis and further development of use cases and applications too.

IFC-SG - Adapting IFC for Some of Our Local Regulatory Requirements 

To ensure our regulatory information can be captured and exported to IFC, the information must first be incorporated in the BIM model and exported to IFC.

IFC allows for customization of properties and object types to the existing IFC entities. While most regulatory information will be represented in existing international IFC standards, some "localization" will need to be carried out to capture selected information unique to the Singapore context.

ifc-10 8 sep

This localized IFC data model that is developed based on the IFC standard to address local regulatory needs is termed as IFC-SG. Some examples include:

  • Defining a customized "BarrierFreeAccessibility" property to associate with a ramp element to indicate that the ramp is designed for accessibility
  • Defining a customized "Driveway" type uner the IfcCivilElement entity, to indicate the driveway object in a project development


Working Closely with BIM Software Partners to Support IFC-SG

To facilitate industry in the preparation of the submission and export to IFC-SG, we are working closely with the BIM software partners on the configurations and templates for their software to support the export for eventual submissions. The BIM software partners regard IFC-SG as important and useful for the local industry, and are supportive of this effort.
IFC-SG software templates, configurations and related documentation will be provided at a later phase, for industry and practitioners to use in the preparation and export of BIM models for submission.


For any feedback or enquiries related to CORENET X, please complete the form here.


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