Use the Snap to Object option to automatically position
the edge of an object using the edge of another object. The Snap
to Object option is available in the Drawing Aids palette and from
the View menu.
When Snap to Object is enabled, an object that you move to within
one grid space of another object snaps to the other object automatically.
If additional snapping options are enabled, the objects must be
closer to each other before the object you are moving snaps.
Snap to Object snaps objects to other objects even if the objects
do not touch. For example, in the following illustration, the bottom
edge of object B snaps to the top edge of object A.
When the Snap to Object option is enabled, you can disable it
temporarily by pressing the Alt key when you position the object.
Pressing the Alt key temporarily enables the option when it is disabled.
Note: Because the Alt key disables the arrow keys,
you cannot use it to toggle Snap to Object on or off when you use
arrow keys to move objects.
When you select multiple objects, the objects are treated as
one object for snapping.