The 3Delight Preferences Dialog
Render Engine tab of the 3Delight Preferences.
Viewing Apps tab of the 3Delight Preferences.
The Render View preference is for selecting the window (and application) in which image layers are displayed during rendering. It can be either the Maya Render View or 3Delight Display.
The Image Viewer option specifies the location of the applications that will be launched to view images. The default application is 3Delight Display.