There are different ways to export from Revit to IFC, here I’ll show a way to preserve correctly all the Project Base Location settings of your project, especially the Elevation (Z coordinate) otherwise usually excluded.
If using Revit 2014
- update it to the latest Service Pack (very important)
- download and install the latest IFC Export for Revit 2014 (from SourceForge or Autodesk Exchange)
- From:* File > Export > IFC*
- Click “Modify Setup…”
- Check “Include IFCSITE elevation in the site locall placement origin” Finally export!