There are several posts out there that talk about the options available to get 3D geometry from Revit to Sketchup many of which refer to the *.FBX format..
We have spent a good deal of time ad effort working with outputs from Revit, Tekla, Bentley and many others and have written the consummate IFC importer for Sketchup with results that out perform what you achieve in many other IFC viewers (Tekla Bimsight, DDS IFC viewer)
In writing the iFC importer we now know more than most what the issue are associated to IFC exports from Revit and would be happy to share that knowledge with others so that you can send Autodesk the feedback necessary to affect change in future versions. As such we invite you to get in touch, send us your models* and we will review them, giving you valuable feedback on the quality shortfalls that prevent your data from being reused in downstream processes such as cost estimation, planning and FM.
* We guarantee complete confidentiality, any model shared with us will be removed from our systems after analysis and communication of our analysis results.