Rhino and Grasshopper to Revit Via IFC Plugins from Geometry Gym

 SSI (Smart Structural Interpreter) is a suite of plugins for Rhino3d and Grasshopper3d that enable BIM and Structure model generation and exchange with Revit via the IFC file format.

The free work in progress plugins are available for download from the Geometry Gym website.

Further reading: Grasshopper-related add-ins. 

Credit: Luke Johnson's What Revit Wants blog.