You can freely download Dxf3DExport, a free add-in for SolidWorks that will transfer 3D geometry from SolidWorks to 3D DXF.-> Telechargement -> Divers (French site)
Just copy Dxf3DExport.dll in the Apps directory of SolidWorks (create it if it does not exist). It will be loaded with SolidWorks.
Messages, menus are a small help file are in english.
Pascal Scanu Atemi (French SolidWorks Solution Partner)