We keep watching IFC readers are difficult to say the least. The fact that there are so many.
There are options fo IFC:
- BEAM IFC
- Visual ARQ has IFC import and actually can deal with the data in Rhino
- Geometry Gym
- BIMDex IFC to Rhino
- IFC into Revit using Rhino.Inside Revit.
- IFCPanel - IFC Panel | Food4Rhino
- Using OpenIFCShell in CPython for direct access to the IFC file and its objects. Rhino.Python has the ability to read and write IFC files using this method.
The OpenIFC shell is quite interesting because then the data can be custom mapped to Rhino objects.