Selecting Tools - Subsections opens a viewer which displays the subsectioning of your circuit in the Sonnet session window. You may view all metalization levels and their subsectioning. You may also open the subsectioning viewer by clicking on the View Subsections button in the main interface window or in the Estimate Memory Results window.
Note that the subsectioning needs to be calculated in response to this command and depending on the complexity and size of your circuit and your computer resources can take some time. If you wish to abort the command, click on the Abort View Subs. button which appears in place of the View Subsections button in the main Cadence Virtuoso Interface window.