Using IFC Shared Parameters
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Not all properties defined in the IFC schema are part of Revit by default, as this would overload the database. It is recommended to add only the parameters needed in a specific project. Frequently used parameters can be added to the project templates.
These can be added to the Revit Project using the Autodesk Parameter Service, which is available since Revit 2023 and automatically retrieves shared parameters through Autodesk Docs:
Alternatively, the IFC shared parameters can also be added using the traditional shared parameters stored in text files. Revit IFC Open Source extension ships with two shared parameter files which are stored in the following folder after the installation
C:\ProgramData\Autodesk\ApplicationPlugins\IFC <Version>.bundle\Contents\
They can also be downloaded from the GitHub repository.
The two files are:
- IFC Shared Parameters-RevitIFCBuiltIn_ALL.txt
- IFC Shared Parameters-RevitIFCBuiltIn-Type_ALL.txt
The shared parameters are added to Revit using the Dialog found in Manage > Project Parameters and it is recommended to use the first file for adding the Instance parameters and the second one for Type parameters.
The reason for having two files is that the IFC schema is based on types and instances, just like Revit. In IFC, however, the same parameter can be attached to instances and types (and can also be given different values), while Revit requires the user to choose between type and instance when assigning a parameter – it is not possible to select both.
Depending on the project requirements, it might be necessary to attach certain properties to both IFC Instance and IFC Type levels. To achieve this, the instance properties from the first file and the type properties from the second can be added. The properties from the second file will display [Type] in the name in Revit, which will however be removed during export.
To illustrate this, let’s assume you need to deliver your doors with the Pset_ DoorCommon containing different FireRating on Type and Instance. Steps necessary:
- Add the Instance property according to the previous screenshot from IFC Shared Parameters-RevitIFCBuiltIn_ALL.txt, assign it to the Door Category, and ideally group it under IFC Parameters (not obligatory but improves the overview).
- Add the Type property from IFC Shared Parameters-RevitIFCBuiltIn-Type_ALL.txt and assign it to the Type this time, select the Door Category, and group it under IFC Parameters.
The result should look like this:
