Sketchup Models (.skp) may be imported into Revit using the Autodesk FormIt Add-in on the Menu.
Note: Since April 2024, Autodesk is no longer actively developing FormIT and the focus has shifted to Forma.
The sketchup file will be converted to a FormIt type file and then used as a reference model to create a Conceptual Mass which can then be analyzed. Sketchup uses faces and more complex models may not be read fully by Revit depending on how layers and materials are set in Sketchup.