By Garry Stockton
If you are new to Navisworks, or simply confused of which file format to use, below you will find a simple explanation.
NWC - Cache Files
NWC files format is not intended for general use. It contains a cached version of the converted Revit model geometry. It allows users to open files into Navisworks which can be saved in NWF or NWD file format. NWC files are created to load the model more quickly when opened next. However, it does not allow users to save NWC file format.
NWD - CAD File
NWD files are lighter than CAD files (less loading time) and users can only save it if they have a licensed version. It is used to publish and share the compiled version of the ongoing project for others to review, even if they do not have Navisworks, they can use Freedom (free viewer). This allows the user to retain the source file and can share a secure NWD file.
NWF - Federated Files
An NWF file contains indexed data of all the model files that are being used. It stores all the other data opened in Navisworks. It is recommended to use the NWF file format while working with an ongoing project as any changes or updates made with the original drawings will get reflected in the next time the model gets opened in Navisworks.