Object snaps enable you to quickly select exact geometric points on existing entities without having to know the exact coordinates of those points. With object snaps, you can select the endpoint of a line or arc, the center point of a circle, the intersection of any two entities, or any other geometrically significant position. You can also use object snaps to draw entities that are tangent or perpendicular to an existing entity.
You can use object snaps whenever the program prompts you to specify a point, for example, if you are drawing a line or other object. To turn on the ESNAP mode, any of the following ways is available:
Execute from Tools-Draft Settings menu option, toggle to Object Snap page, and tick the Object Snap On checkbox.
Right click on the ESNAP button on Status bar, choose On.
When using object snaps, the program recognizes only visible objects or visible portions of objects. You cannot snap to objects on layers that have been turned off or to the blank portions of dashed lines.
When Object Snaps is turned on, a marker and a tooltip are displayed when you move the cursor over an object snap location on an object.
Setting object snaps
You can set object snaps using any of the following methods:
Choose Tools>Draft Settings > Object Snap, then click one of the object snap tools.
On the Entity Snaps toolbar, click one of the object snap tools.
On the command line, type an object snap command.
On the status bar, right click ESNAP, choose settings.
Press and hold down the Shift key while right clicking anywhere within the drawing window to display the object snap shortcut menu, and then choose the object snap you want to set.
Object Snap settings
If you need to use one or more object snaps repeatedly, you can turn on running object snaps on the Grid and Snap tab of Draft Settings dialog box. The object snap mode keeps on unless you turn it off. For example, you can use an object snap to draw a line to the center of a circle.
If several object snaps on, the system chooses automatically the most suitable object snap. If there are two possible object snaps at the selection area, the system choose the one that is closer to the center of target box.
If you turn several object snaps on, you need to check which one is in effect when you specify a point. If several object snaps are eligible at a given location, press the TAB key to cycle through the possibilities before you specify the point.
Object Snap Restrictions
With the object snap on, you can snap objects only visible on the screen, including objects on locked layers, layout viewport boundaries, and polyline segments. You cannot snap to objects that are not visible, including objects that are not displayed, objects on turned-off or frozen layers, or the blank portions of dashed lines.
The object snap in available only when you are prompted to specify a point. There isn't any information about object snap displayed if you try to use an object snap at the Command prompt.
The automatic snap tool is a visual aid tool for snapping that help you see and use object snaps more efficiently. When any object snap is on, the system displays a marker and a tooltip when you move your cursor on over a snap point. AutoSnap turns on automatically when an object snap is on. By default, AutoSnap mark, tooltip and magnet are on. You can change the settings of AutoSnap on the Options dialog box.
AutoSnap consists of the following snap tools:
Marker. The object snap location is displayed when the cursor moves over or near an object. Marker shape is determined by the snap it is marking.
Tooltip. Indicates which part of the object you are snapping to in a flag at the cursor location.
Magnet. Attracts and locks the cursor onto the nearest detected snap points. Provides a visual that is similar to snapping to a grid.
Aperture box. Surrounds the crosshairs and defines an area within which, when you move the cursor, system evaluates objects for object snaps. You can determine the aperture box is displayed or not, and the aperture box size can be changed too.
To change the size of the object snap target box
Choose Tools>Options > Drafting.
Under Aperture Size, slide to adjust the desired size.
APERTURE: Controls the size of the object snap target box
OPTIONS: Customizes the ZWCAD settings
OSNAP: Sets running object snap modes
System Variables Reference
APBOX: Turns the AutoSnap aperture box on or off
AUTOSNAP: Controls AutoSnap marker, tooltip, and magnet
OSMODE: Sets running Object Snap modes
OSNAPCOORD: Controls whether coordinates entered on the command line override running object snaps