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IFC file: all you need to know

IFC file: What is it and how to open it

An IFC file is a standard file format for exchanging building models’ information between AEC professionals using different software

The introduction of the IFC file was a true revolution for the digital AEC world representing a new common language to all operators involved in the entire life cycle of a building or infrastructure project.

But what is an IFC file? What’s it for? and how is it structured? How do you visualize?

In this article I’ll be answering these and other questions, providing various practical aspects behind this topic and, therefore, what it can do to help you in your daily work.

Additionally, I’ll explain how to view and manage it with a free online IFC viewer.

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What is an IFC file

The IFC file is an open, non-proprietary file format, international standard ISO 16739, and can be used to exchange and share data, during design, construction, operation and maintenance phases, between all the figures and the various applications developed by different software houses without the need for them to support native (proprietary) files.

What is an IFC file

Interoperability in a closed and open system

On the other hand, the IFC is not only an exchange format, but a schema, i.e. an organised data structure according to precise rules: the IFC schema can be thought of as a ‘filing system’ for organising and transporting digital data.

IFC file format

The IFC file can be encoded in different formats, each one with its own characteristics.

The official formats published on the buildingSmart International website are:

  • .ifc: default file format based on the ISO STEP Physical Format (SPF) standard
  • .ifc-xml: encoding based on the XML language
  • .ifc-zip: a compressed archive of one of these formats
  • .ttl: encoding based on the ifcOWL language
  • .rdf: encoding based on the ifcOWL language

According to buildingSMART International, the IFC format is the main tool for Open BIM implementation.

How to open an IFC file

To open, an IFC file you could follow two methods:

  • purchase a BIM software that supports importing IFC Files;
  • use a free online BIM and IFC viewer.

Using an online viewer you don’t have to download any application, just:

  • create your account and access usBIM
  • import in to a folder and open your IFC file
  • view the 3D model, entities and properties.

IFC file structure

The IFC format allows you to produce files that include:

  • geometric information of the various entities of ‘simple’ building components (such as walls, doors, floors, etc.) and all associated data;
  • alphanumeric information (properties, quantities, classification, etc.) specifying their parameters, physical properties, construction information, maintenance information, etc.

The logic of the IFC is based on 3 fundamental concepts, which represent the structure itself and define:

  • IfcObjectDefinition: entities (objects)
  • IfcRelationship: entity relationships
  • IfcPropertyDefinition: properties associated to entities.

A BIM model is a model consisting of specific parametric entities that have relationships with each other and whose technical characteristics are described through properties.

To know more about this topic, take a look at the below articles:

Model View Definition and BIM

MVDs are subsets of the IFC schema as defined by buildingSMART International that group together certain information useful for specific workflows or uses.

These “filtered views” are very useful as they make the data exchange process simpler and avoid sharing unnecessary or redundant notions, following standardised procedures.

The following image shows the idea of the completeness of the IFC schema and how an MVD specification is able to streamline it according to certain information.


IFC schema and MVD variation

As it can be seen from the image above, the MVD is a filtered view that takes in some or all of the information from the entire schema.

Therefore, an MVD function does not depend on the many software packages on the market, but on the information to be shared.

This is the result of a specific need, i.e. to transfer the information necessary for a specific situation, facilitating the exchange between the software available at an international level.

Read the article “Model View Definition (MVD) and BIM data exchange” to know more about this topic.

Classification systems in the construction sector

A classification system is the grouping and coding method that allows you to organise entities.

There are different classification systems, with different ways of categorising them, such as:

  • Omniclass
  • Uniclass
  • Uniformat
  • Masterformat
  • etc.

To know everything about classification systems in buildings I suggest the article “IFC and classification systems in the construction sector“.

Before concluding here are two practical indications that meet the most common needs of technicians: open an IFC file and convert a DWG file to IFC.

How to convert a DWG into IFC file

If you are working on a DWG project or 3D block and you need to convert it in IFC using a simple and reliable tool, follow the steps below.

  1. Download and install the usBIM.viewer+ for free;
  2. Choose the option Create document from 3D file
  3. Select the 3D model to convert
  4. From the toolbar, click on Export IFC file.

Having to convert files from DWG, SKP, OBJ, 3DS format to IFC format is a frequent need today and for which it will be necessary to use a specific software.

Whitepaper for download

Get hold of this Whitepaper (below) with a collection of some articles on the IFC topic and published by BibLus.

To find out more about the IFC file format, download the ACCA software whitepaper now!