By default, the Revit exporter exports the original building geometry, and not the part information. To change this behavior, the user must follow the steps below. The steps below require the installation of the Export Alternate UI.
The output depends on whether or not the "Export parts as building elements" option is enabled or disabled. If it is disabled (the default), parts will be exported as IFCBUILDINGELEMENTPART, contained in a container of the appropriate type. If the option is enabled, no container is exported, and instead each part is exported as a separate entity of the appropriate type.
Example:
A user creates a wall, and divides it into 4 parts.
With "Export parts as building elements" disabled, the IFC file will contain one IFCWALL, with no geometry, that contains 4 IFCBUILDINGELEMENTPARTS, each with their respective part geometry.
With "Export parts as building elements" enabled, the IFC file will contain four IFCWALLs, each with their respective part geometry.
It is possible to export parts without the alternate UI. The steps are as follows:
This is essentially the same as above, without the possibility to export parts as building elements.