One of the biggest features in the new release of Navisworks 2013, is that you can now directly load Revit .RVT files into Navisworks in addition to exporting .NWC files from Revit.
We will support the loading Revit files from three previous releases, so we will load files created in Revit 2010, 2011 and 2012 as well as the current release 2013.
Most of the time these will load correctly into Navisworks with no further work required; however there will be occasions where you receive the message "There were errors encountered while opening the Revit model. Please open the file in Revit and fix the errors".
This means you will need to fix the file in Revit 2013, this fixes parts of the model that cannot be converted inside of Navisworks. When you save the file in Revit 2013, Navisworks can then load those elements.
If you do not own a copy of Revit 2013 then you can still export NWC files from the version of Revit you have installed on the machine. Just install the Revit Exporters through 'Add or Remove programs' if they are not already installed then you can go to Add-Ins > External Tools to export a Navisworks 2013 NWC file.