I've just found this and need to share....
From the company that spend so much time in court righting for the rights and the ownership to the dwg and dxf format, Autodesk has donated the STL Exporter for Revit to Open Source under the LGPL 2.1 license. The source code, latest builds and user/technical documentation will be available at the following site. You will be able to view and edit the source code to suit your needs.
This is something Autodesk has never done before with an add-in/plug-in/app for Autodesk Revit or any other Autodesk product. (See MapGuide for the first Autodesk contributed open source project.)
The code hackers and tinkerers among you are probably saying “cool! – now I can play with it and make it suit my needs”.
The skeptics among you are probably saying “Autodesk is trying to dump responsibility for this thing on the user so they don’t have to support it”. To the skeptics I would recommend you read on. ...... Click Here to visit the whole posting over at BIM Apps.