.NWD File Extension
What is an NWD file?
CAD file created by Navisworks, a program used for reviewing and simulating architectural designs; contains CAD models, camera viewpoints, animations, and user comments; used for presentations and for showing clashes between CAD designs.
Unlike .NWF files, which only store references to the source data files, NWD files include all source data files so the document can be viewed standalone. In this manner, NWD files act as a snapshot of the current project's file set.
You can view NWD files with Navisworks Freedom, and you can publish NWD files in Navisworks Manage by choosing File → Publish from the application menu. Both Freedom and Manage are included in the Navisworks suite.