If you have access to Sonnet software from the same computer on which you are running Virtuoso, it is possible to open the Virtuoso SonnetEM View in the project viewer for viewing or editing. Selecting Tools - Project Viewer - View 2D from the main menu in the Cadence Virtuoso Interface main window, the Sonnet session window is opened with the Sonnet project translated from your Virtuoso SonnetEM View opened in a project editor tab in View Only mode.
When you view your circuit in the normal 2D view in the project viewer, you are always “on” a particular level, as shown by the level drop list in the Project Viewer tool bar. The top level is always “0” and increases as you move downward through the box. You can switch levels by using your arrow keys, or using the level drop list. By default, all polygons on your present level are shown in solid, and all polygons on all other levels are shown as dashed outlines.