Autodesk says it is releasing its IFC exporter so that users can more directly control exported elements. Users may, for example, change the representation of exported elements, should they find another, more useful encoding.
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Access to the Revit IFC exporter open source code, as well as information regarding the Revit IFC Exporter Open Source Committee, can be found at the SourceForge repository at http://sourceforge.net/projects/ifcexporter.
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GraphicSpeak � Autodesk releases Revit IFC Exporter as open source
