2D entity snaps

Entity snaps enable you to quickly select exact geometric points on existing entities without having to know the exact coordinates of those points.

With entity snaps, you can select the end point 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 entity snaps to draw entities that are tangent or perpendicular to an existing entity. You can use entity snaps any time you need to specify a point.

You can work with entity snaps in one of two ways:

  • Enable a running entity snap that remains in effect until you turn it off by choosing an entity snap when no other command is active.
  • Enable a one-time entity snap for a single selection by choosing an entity snap when another command is active. You can also use a one-time entity snap to override a running entity snap.

When using entity snaps, the program recognizes only visible entities or visible portions of entities. You cannot snap to entities on layers that have been turned off or to the blank portions of dashed lines.

If the APBOX system variable is on, the entity Snap Aperture Box is added to the crosshairs when one or more entity snaps are active.

When you move the cross hairs, the program snaps to the snap point closest to the center of the Snap Aperture Box. The Snap Marker indicates the current snap point.

The DRAGSNAP system variable controls the snap behavior while dragging, providing an increased WYSIWIG experience. DRAGSNAP controls whether rubber band dynamics are displayed at the current cursor location or at the current entity snap location. DRAGSNAP applies to all modify commands that display dynamics, such as COPY, PASTECLIP, PASTEBLOCK, MOVE, ROTATE, MIRROR, SCALE and STRETCH.

  • DRAGSNAP = 0 (Default): dragged entities display at the cursor location.
  • DRAGSNAP = 1: dragged entities display at the current entity snap location.

The OSOPTIONS system variable suppresses entity snaps on certain entity types. The value is stored as a bitcode using the sum of the values of the selected options.

  • 1: Entity snapping is disabled for hatch entities.
  • 2: Entity snapping is disabled for geometry with negative Z values when using a dynamic UCS.
  • 4: Entity snapping is disabled for endpoints of dimension extension lines.
Note:  Press the TAB key, without moving the mouse, to cycle through all possible entity snaps available at the current cursor position.

Defining the 2D Entity Snap system variables

Right click the ESNAP field in the Status bar then choose settings in the context menu. The Settings dialog box displays with the 2D and 3D entity snaps settings expanded.

2D Entity Snap options

Icon Description
Sets the OSNAPZ system variable to Ignore entity snap elevation, replacing the Z coordinate of the snapped point with the current value of the ELEVATION system variable.

The 3d snap marker (1) displays the identified 3d point, the snap marker (2) displays at the current Elevation height.

Disables the Ignore hatches option of the OSOPTIONS system variable, thus allowing to snap to hatches.
Disables the Entity snap to negative-z option of the OSOPTIONS system variable, thus allowing entity snaps with a negative z-value when a Dynamic UCS is active.
Disables the Ignore endpoints of dimension extension lines option of the OSOPTIONS system variable, thus allowing entity snaps to dimension extension lines.

Entity Snap Modes

Name Icon Marker Context menu shortcut* Transparent shortcut** Description
TK tk Use temporary tracking points. Prompts you to identify temporary points; press Enter to accept the last temporary point.
MTP 2 mtp Snaps to a point in the middle between two points. Prompts you to identify two points.
ENDPOINT E end Snaps to the nearest endpoint of an entity or polyline segment.
MIDPOINT M mid Snaps to the midpoint of an entity or polyline segment.
NEAREST N nea Snaps to the nearest point on an entity.
CENTER C cen Snaps to the center point of an arc, circle, polygon, ellipse or elliptical arc.
GEOMETRIC CENTER G gce Snaps to the centroid of any closed polylines and splines, planar 3d polylines, regions and planar faces of 3D solids.
PERPENDICULAR P per Snaps to the perpendicular point of another entity. You can snap to an arc, circle, ellipse, line, polyline, infinite line, ray, spline or edge of a plane to form a perpendicular alignment with that entity or with an extension of that entity.
PARALLEL L par Displays a tracking line parallel to the selected entity.
TANGENT T tan Snaps to the point on an arc, ellipse, spline or circle that, when connected to the previous point, forms a line tangent to that entity.
QUADRANT Q qua Snaps to the closest quadrant of an arc, circle, ellipse, or elliptical arc.
INSERTION I ins Snaps to the insertion point of an attribute, block or text entity.
NODE O

poi

nod

Snaps to a point entity.
INTERSECTION R int Snaps to the intersection of any combination of entities.
APPARENT INTERSECTION A app

Snaps to the apparent intersection in the current view of two entities that do not intersect in three-dimensional space.

Snaps also to the intersection of any combination of entities.

EXTENSION X ext Snaps to the extension of an entity or to the intersection of the extension of two entities.
NONE Y non Turns off all entity snap modes.

* Type this letter to quickly select the entity snap mode in the right click context menu.

** Type the transparent shortcut in the Command line when a command prompts for a point.

Other running entity snaps are temporarily disabled.

Setting the Entity snaps

Do one of the following:

  • Press and hold the Shift key, then right click and select the Entity Snap mode in the context menu.

    The icons of the currently active Entity Snap modes are outlined.

  • Click the buttons on the Entity Snaps toolbar.

    The buttons of the currently active entity snap modes are pressed.

When no command is active, the above procedures toggle the Entity Snap modes on/off.

When a command is active, the above procedures set a 'one shot' override of the current Entity Snap modes.

Alternatively, you can type a single letter shortcut as indicated in the table below.

To toggle the Entity Snaps on/off:

  • Click the ESNAP field in the Status Bar.
  • Press the F3 function key.

Working with multiple Entity Snap modes

  1. Move the cursor to the entity you want to snap.

    One of the active Entity Snap modes markers display.

  2. Do not move the mouse and press the TAB key.

    The entity the snap point is on highlights.

  3. Do one of the following:

    • Click to accept the snap point.

    • Press the TAB key.

      The next possible Entity Snap mode marker displays.

      The entity the snap point is on highlights.

  4. (option) Repeat step 3 until the right snap point is found.

Snapping to the extension of two entities

  1. If not already on, turn on the Extension Entity Snap mode.

  2. Launch an entity creation command, for example LINE.

  3. Move the cursor over the endpoint of the first entity (1).

    A small red cross indicates the entity is marked for extension.

  4. Move the cursor over the endpoint of the second entity (2).

    A small red cross indicates the entity is marked for extension.

  5. Move the cursor near the intersection of the extensions of the two entities.

    An X indicates the intersection (3).

  6. Click to accept the snap point.
Note: You can snap to the extension of lines, polylines, arcs and elliptical arcs.

Using the Middle of 2 points snap mode

  1. When prompted to specify a point, do one of the following:
    • Activate the Snap to the middle of 2 points snap mode ().

    • Type mtp or m2p in the Command line and press Enter.

    You are prompted: First point of mid:

  2. Specify the first point.

    You are prompted: Second point of mid:

  3. Specify the second point.

    The point in the middle of the two points is snapped.

Using the Parallel entity snap mode

  1. Make sure Entity Snap Tracking is active.

  2. Launch an entity create command to create a linear entity (for example Line).

  3. Specify the first point of the entity.

    The line displays dynamically.

  4. Press and hold the Shift key, then right click and choose Snap to parallel () in the context menu.

  5. Hover the cursor over the entity you want to draw parallel to.

    The Parallel Entity Snap marker () displays on the selected entity.

    Wait until a small cross (+) indicates the entity is recognized.

  6. Move the cursor in order to place the dynamics of the line more or less parallel to the selected entity.

    A tracking line displays from the start point of the line.

  7. Do one of the following to specify the second point while the tracking line displays:
    • Click a point.

    • Enter the desired length and press Enter.

    • Use a second entity snap tracking point, then move the cursor to the intersection of the parallel tracking line and the second entity snap tracking line.