The Export 3D App File option in the file menu will create a copy of the currently open drill as a .3da file type. These .3da file types, also known as mobile app files, can be viewed in the 3D Viewer application.
To create a mobile app file, first open the drill from the File menu. Once the drill is open, go to the File menu and choose Export File then Export 3D App File. A new window will open where you can give the file a name, and specify which directory you would like to save the file to. Once you have decided on a destination and file name, press Save.