.3DD File Extension
File TypeArcGlobe Document
What is a 3DD file?
GIS data file created by ArcGlobe, a visualization application used to view 3D GIS datasets; stores a reference to a geodatabase, which contains the spatial content and output results created by the software's geoprocessing operations; can store GIS data as a collection of three-dimensional layers; used for saving and loading views of 3D GIS datasets.
ArcGlobe is included with the ArcGIS Desktop software package.