IFC Revit Export: Best Practices With Simon MOREAU (1/2)
This is the first part of a two part article summarizing all the features I wish I knew before I started exporting IFC from Revit.
I've been working with IFC a lot lately and getting the correct values from various modeling software can get tricky. To check if my demands around IFC are realistic, I need to understand the possibilities offered by these modeling software. So I spent some time understanding Revit's IFC export plugin.If you are relying on IFC for your process, you should first download the latest version of the IFC plugin for Revit. This plugin seamlessly replaces Revit's built-in IFC module and makes improvements to standard IFC import and export. Its source code is available on Source forge and you can even suggest your own improvement.
Selection of levels to export
The deactivation of the parameter "Building floor»On a Revit level removes the IFCBuildingStorey corresponding file of the exported IFC file. The elements initially based on this level are associated with the IfcBuildingStorey located immediately below.
Exporting Revit Properties
Since my last article, the exporter IFC has made some progress, and new options are available.Export all Revit properties
Activation of "Export Revit Property SetsIn the IFC export UI sends all Revit properties in custom property groups named after the parameter group in Revit.Creating your own property sets
With a user-created configuration text file, you can create your own property sets and populate them with Revit settings. In this configuration file, a first line describes the set of properties: its name, whether it will be associated with instances (I) or types (T) and the list of elements for which to create the custom property group. The following lines list all the properties in the property group, their names, types, and associated Revit parameters.
Here is an example of a configuration file used to export the Create and Demolition phases of each wall and roof into a new property group named "Phases".
Creation PhaseTextPhase Created
Demolition PhaseTextPhase Demolished
This configuration file is loaded into the "Export user-defined property sets"from the IFC export user interface:
The mapping text file allows you to send Revit values in any IFC parameter. Each line in this file links a Revit parameter to an IFC parameter. However, you can only use the "official" IFC parameter, contained in one of the property sets defined in the specification. Also, the data type of the IFC property must be the same as the Revit parameter. If you need a different setting, you will need to create your own property groups.
Here is an example of the mapping file used to export the "Analytical construction" value of each gate in the value Reference from IFC:
The IfcZones are groups ofIfcSpaces used to define zones in a building. To create these IfcZones in Revit, two methods are available, one for them MEP spaces and the other for coins.
The grouping of MEP spaces with HVAC zones creates IfcZones in the exported IFC. You can also export the settings of these HVAC zones to the property set PSet_ZoneCommon or any other set of properties.
Here you can see the description of the area, however, PSet_ZoneCommon is not created.
We also note that although MEP Spaces and Rooms are both exported to IfcSpace, the exporter adds its original category in the Description field of IFC.
In the second part of this post, we'll explore how to add Classifications, IfcZones, and QuantitySets to your IFC file. See you soon !
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