On the Select Tools tab 
on PathFinder, click the Create Zone button.
In the graphics window or PathFinder, define the volumetric extent of the zone by selecting one or more assembly components, and then click the Accept (check mark) button.
The volumetric extent is displayed in the graphics window.
If you want to modify the size of the zone, go to step 4, otherwise click the Next button, then click the Finish button.
To modify the size of the zone, click a face on the zone boundary box, then click an assembly component vertex or a point in free space.
Tip:
You can display and hide the zone boundary boxes in the graphics window using the View tab→Show group→Zones command.
You can display, hide, or select the parts in a zone using the zones shortcut menu commands on the Select Tools tab when you select a zone entry in the list.
You can use the Drawing View Wizard to select an assembly zone volume to be shown in a drawing view. You can choose an assembly zone from the .cfg, PMI model view, or Zone list on the Drawing View Options page of the Drawing View Wizard.