Existing Contours
This command displays all the contours that represent the existing
surface (For contouring options see Display Options). Clicking on
Cut/Fill Labels from the menu runs the command and puts a check
mark on the menu. Picking again turns it off.
When Existing Contours is checked than all the contours for the
existing surface will be displayed. If it is not checked they will
not be displayed.
Prerequisite: existing surface
Keyboard Command: set_display_exist_ctr
