This open source version can override the version that comes standard with shipped Revit. Revit 2013 contains both IFC export and IFC export UI overrides, which contains options not available in the regular UI, such as ifcXML and ifcZIP support.

http://sourceforge.net/p/ifcexporter/home/Home/

Please note that there are three separate installers in the Downloads section for this project:

  1. 2012 – This contains the IFC Exporter for Revit installer compatible with the Revit 2012 series of products. The latest version is intended to be used with Revit 2012 Update Release 2, although earlier versions are available.
  2. 2013 – This contains the IFC Exporter for Revit installer compatible with the Revit 2013 series of products. For more information on the difference between 2012 and 2013, check out [What’s new in 2013].
  3. 2013 UI – This contains the IFC alternate Exporter UI for Revit installer compatible with the Revit 2013 series of products. There is no Revit 2012 version of this UI. This replaces the default IFC Export UI in Revit, and adds new functionality such as saving export configurations, and new export options such as saving to ifcXML and ifcZIP file formats.