IFC class mapping file

IFC class mapping allows you to recognize IFC entities in your authoring software without loosing any info or data. Here’s how it works and how to use it

Are you dealing with having to import an IFC model in your BIM authoring software (Edificius, Revit, Archicad, etc.) but want to be sure that the original entities are recognized correctly or detected? More in general, do you need to exchange information between authoring software by means of the IFC standard format? In this post I’ll be explaining what the  IFC class mapping file concept is all about and how it can be useful for reading and detecting IFC entities.

I’ll then show you how you can modify some of the IFC properties without even needing to have a BIM authoring software.

What is the IFC class mapping file?

IFC class mapping is basically a text file that “maps” the categories generated by any sort of authoring software so that they correspond to the same category types as defined by another 3D modelling application.

In other words, we’re talking about an information converter.

Let’s see a quick example to clarify the concept. Let’s suppose that we need to load an IFC file in Revit that was originally exported by Edificius or Archicad or any other BIM authoring software. To ensure data compatibility, I would definitely need to find the same entities present in the IFC file also available in the Revit native file. Therefore, I’ll definitely need an information converter based on the IFC class mapping file.

This means that I’ll need to be able to read the same entity data in the source IFC model(doors, windows, slabs and walls, etc.) also in the resulting BIM authoring file without loosing any information. So, in the case of the door object (IfcDoor), this must be recognized as a door entity in Revit too (“door” family).

With an adequate class mapping definition, the authoring software will be able to recognize the corresponding entities correctly.

Figure | IFC class mapping

IFC class mapping in Edificius

To correctly map the entities of an IFC file with the corresponding entities in Edificius (the BIM authoring for architectural design) we need to start off by creating a new IFC document.

Here’s how to proceed in just 2 simple steps:

1. click on File>New>IFC document
   
2. from the file browser dialog, select the IFC file and click Open to load it.

Edificius will automatically recognize the IFC entities generated by modelling software capable of exporting in this format.

At this point you can seamlessly manage the file with dedicated tools available in Edificius.

The animation below shows how straight-forward it is to quickly load an IFC file in Edificius in order to automatically match its entities with the corresponding Edificius entities.

How to create a new IFC document with Edificius

IFC class mapping file in Revit

1. click File>Open >IFC Options
2. in the Import IFC Options dialog, click Load.
   
3. in the Load IFC Class Mapping File dialog, navigate to an IFC class mapping file, select it, and click Open
4. in the Import IFC Options dialog, click OK.

After loading the IFC class mapping file), you can open the IFC file from any other 3D modelling application.

How to load an IFC class mapping file in Revit

If you need to export the IFC file with Revit:

1. download the latest official additional component “IFC 2018” (year version based on the Revit version in use)
2. export IFC from Revit
3. click on the Export> IFC button
4. select the IFC 2×3 Coordination View 2.0 for which the software is also certified
5. hide the elements that you do not need to export.

Property Mapping for IFC Import – Archicad

For Archicad, to get the same the same correspondence between its entities and the entities of an IFC file, follow the simple steps below:

1. click on File> Interoperability> IFC> IFC Translators
   
2. select IFC Properties or ARCHICAD Properties
   

Archicad interface | Property mapping

If you choose the predefined option, IFC Properties:

• the software will automatically import all the IFC element related properties
• the data is available as IFC Property sets in various parts of the software interface (such as Find and Select and Scheme settings)
• property mapping is no longer necessary.

With the ARCHICAD Properties option:

• the mapping table is activated in order to choose which IFC Property values are to be associated with the Archicad properties
• each IFC property in the list (defined using the first column from the left) is mapped to an Archicad property
• in the current project file, new Archicad properties aren’t generated
• the IFC properties that are not listed in the mapping table, are ignored during import.

How to open and edit an IFC file with a freeware application

If you need to view or edit an IFC file but without having to use a BIM authoring software, you can use usBIM.viewer+, the free viewer that offers a series of useful tools that simplify IFC model management.

Here’s how simple it is:

• download and install usBIM.viewer+ for free
• open the software, then click on the Create Document from IFC function
• browse and select the IFC file to open
• view the model in 3D and consult the entity properties in the panel on the right.

For further info on this topic.

If you prefer an online solution, you can use usBIM.browser, the free application of the integrated usBIM system, which allows you to view any 3D model (online Revit file viewer, EDF viewer, OBJ viewer, etc.) and perform a number of operations directly on the IFC.