When you import geometry, using the Import command on the File menu, in most cases a dialog is displayed that asks whether you want the imported geometry to be added to the scene, or to replace the scene entirely. For example:

Merge objects with current scene—Merges imported data with the current scene.

Completely replace current scene—Completely replaces the current scene with the imported data.

In general, once you respond to this dialog, a second dialog with geometry-specific options is displayed, as described in the topics that follow. (For some geometry formats, only one dialog appears, and these options are merged with the geometry-specific options.)