This is the .NET code used by Revit 2019 and Revit LT 2019 to support IFC. The open source version can override the version that comes standard with shipped Revit. This contains the source code for Link IFC, IFC export and the IFC export UI.
We are in the process of greatly simplifying the build progress. We will add notes shortly once this work is complete.
Release notes can be found here: link to Wiki Release Notes page
Help for IFC in general can be found here.
An archive of the original SourceForge forums can be found here.
The Revit IFC open source uses the Lesser General Public License version 2.0 (LGPLv2). It relies on ANTLR 4 which uses the BSD license.