Entity Snaps

Commands: 2DINTERSECTION, 3DINTERSECTION, NEAREST, CENTER, ENDPOINT, EXTENSION, FROM, GCENTER, INSERTION, INTERSECTION, MIDPOINT, MTP, NONE, PARALLEL, PERPENDICULAR, POINT, QUADRANT, TANGENT

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 rubberband 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.

To define the Entity Snap settings

1. Open the Settings dialog.

2. In the Settings dialog, expand the Program Options settings class.

3. Under Program Options expand the Display settings group, then scroll down to the Entity Snap settings.

          4. Under Drawing expand the Drafting settings group then go to Coordinate Input > Entity Snaps .

To set the Entity Snaps

Do one of the following:

• Click the buttons on the Entity Snaps toolbar.
  The buttons of the currently active entity snap modes are pressed.
  
  
• 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.
  
  

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.

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 bar when a command prompts for a point. Other running entity snaps are temporarily disabled.

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; 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.

To snap to the extension of two entities

1. If not already on, turn on the Extension Entity Snap mode ().
2. Launch a drawing tool, e.g. Draw Line.
3. Move the cursor over the endpoint of the first entity (1).
   A small cross () indicates the entity is marked for extension.
4. Move the cursor over the endpoint of the second entity (2).
   A small 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.

Using temporary tracking points

When using temporary tracking points, Polar Tracking must be on and it is recommended to have dynamic dimensions active as well.

1. Whenever a command prompts for a point, do one of the following:

• Click the mouse wheel.
• Click the Temporay tracking points tool button () on the Entity Snaps toolbar.
• Hold down the Shift key, then right click and choose Temporay tracking points in the context menu.
• Type TK in the command bar, then press Enter.

The command is suspended temporarily.

You are prompted: Specify first temporary tracking point:

     2. Enter a point, e.g. use an entity snap to specify a point.
You are prompted: Specify next temporary tracking point (press ENTER to end)

     3. Do one of the following:

• Enter a point.
• Press Enter to accept the last temporary tracking.

The command resumes.

Using 'Middle of 2 points' snap

1. When prompted to specify a point, do one of the following:

• Click the Snap to the middle of 2 points button () on the Entity Snaps toolbar.
• Type mtp or m2p in the command bar, then press Enter.
• Press and hold the Shift key, then right click and choose Snap to middle of 2 points in the context menu.

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

1. Make sure Entity Snap Tracking is active.
2. Launch an entity create command to create a linear entity (e.g. Line).
3. Specify the first point of the entity.
   The line displays dynamically.
4. Do one of the following:
   • Press and hold the Shift key, then right click and choose Snap to parallel in the context menu.
   • Click the Snap to parallel tool button () in the Entity Snaps toolbar.
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.

Geometric Relations

When dragging a grip of a line, polyline, arc or a circle the geometric relation (perpendicular or tangent) of the entity being edited with crossing or nearby other lines, polylines, arcs or circles is indicated. A snap marker displays and the other entity highlights when the current position of the dragged entity is perpendicular or tangent within the distance defined by the APERTURE system variable. This feature is controlled by the GEOMRELATIONS system variable.

In the images below the red grip of the line is dragged. Depending on the position of the dragged grip the line is nearly perpendicular to the other line (top) or the circle (middle) or tangent to the circle (bottom). Click when the desired position is reached.