Working with a Leader Dimension Object on a PCB in Altium Designer

This document is no longer available beyond version 21. Information can now be found here: Dimensions for version 24


Parent page: PCB Design Objects

A placed Leader Dimensions
A placed Leader Dimensions


A leader dimension is a group design object. It allows for the labeling of an object, point or area. The label text can be encapsulated in a circle, a square, or not at all, while the pointer can be an arrow or a dot.


Leader dimension objects are available for placement in the PCB editor only. Use one of the following methods to place a leader dimension:

  • Choose Place » Dimension » Leader from the main menus.
  • Click the Leader Dimension button () in the drop-down on the Active Bar located at the top of the design space. (Click and hold an Active Bar button to access other related commands. Once a command has been used, it will become the topmost item on that section of the Active Bar).
  • Click the  button on the Place Dimension drop-down () of the Utilities toolbar.
  • Right-click in the design space then choose the Place » Dimension » Leader command from the context menu.


After launching the command, the cursor will change to a cross-hair and you will enter dimension placement mode. Placement is made by performing the following sequence of actions:

  1. Position the cursor then click or press Enter to anchor the dimension start point (the location of the arrowhead or dot).
  2. Move the cursor then click or press Enter to anchor a series of vertex points that define the shape of the leader.
  3. After placing the final required vertex point, right-click or press Esc to effect placement of the text label and exit placement mode.
When dimensioning an object, anchor points become available to you that highlight where the dimension can be attached. The point nearest the cursor will be the one used and where the dimension will attach if you click or press Enter.

Additional actions that can be performed during placement are:

  • Press the Tab key to pause the placement and access the Leader mode of the Properties panel from where its properties can be changed on the fly. Click the pause button overlay ( ) to resume placement.
  • Press the + and - keys (on the numeric keypad) to cycle forward and backward through all visible layers in the design to change placement layer quickly. Alternatively, use the Ctrl+Mouse Wheel shortcut to cycle through the available layers.
  • Press Spacebar to toggle the dimensioning direction between horizontal and vertical.
While attributes can be modified during placement (Tab to bring up associated properties panel), keep in mind that these will become the default settings for further placement unless the Permanent option on the PCB Editor – Defaults page of the Preferences dialog is enabled. When this option is enabled, changes made will affect only the object being placed and subsequent objects placed during the same placement session.

Graphical Editing

This method of editing allows you to select a placed leader dimension object directly in the design space and change properties such as the position of its text, its shape and its reference point.

When a leader dimension object is selected, the following editing handles are available:

A selected Leader Dimension
A selected Leader Dimension

  • Click and drag A to move the start point of the dimension (i.e. the position of the arrowhead).
  • Click and drag B to move the end point of the dimension (i.e. the position of the text label).
  • Click and drag intermediate handles to change the shape of the leader.
Handle A allows for a re-definable reference; once the dimension is detached from a reference object, it becomes non-referenced and can be moved for attachment to a different reference point or object.

If the leader dimension object is totally non-referenced (i.e. it is not attached to a reference design object), click anywhere on it away from editing handles then drag to reposition it. While dragging, the leader dimension can be rotated or mirrored:

  • Press the Spacebar to rotate the leader dimension counterclockwise or Shift+Spacebar for clockwise rotation. Rotation is in accordance with the value for the Rotation Step defined on the PCB Editor – General page of the Preferences dialog.
  • Press the X or Y keys to mirror the leader dimension along the X-axis or Y-axis.
If attempting to graphically modify an object that has its Locked property enabled, a dialog will appear asking for confirmation to proceed with the edit. If the Protect Locked Objects option is enabled on the PCB Editor – General page of the Preferences dialog and the Locked option for that design object is enabled as well, that object cannot be graphically edited. Double-click the locked object to select it then disable the Locked property in the Properties or List panel or disable the Protect Locked Objects option to graphically edit the object.

Non-Graphical Editing

The following methods of non-graphical editing are available.

Editing via the Leader Dialog or Properties Panel

Properties page: Leader Dimension Properties

This method of editing uses the associated Leader dialog and Properties panel to modify the properties of a Leader Dimension object.

The Leader dialog (the first image) and the Leader mode of the Properties panel (the second image) 
The Leader dialog (the first image) and the Leader mode of the Properties panel (the second image)

During placement, the Leader mode of the Properties panel can be accessed by pressing the Tab key. Once the Leader Dimension object is placed, all options appear.

After placement, the Leader dialog can be accessed by:

  • Double-clicking on the placed Leader object.
  • Placing the cursor over the Leader Dimension object, right-clicking then choosing Properties from the context menu.

After placement, the Leader mode of the Properties panel can be accessed in one of the following ways:

  • If the Properties panel is already active, select the Leader Dimension object.
  • After selecting the Leader Dimension object, select the Properties panel from the Panels button at the bottom right of the design space or select View » Panels » Properties from the main menus.
If the Double Click Runs Interactive Properties option is disabled (default) on the PCB Editor – General page of the Preferences dialog, when the primitive is double-clicked or you right-click on a selected primitive then choose Properties, the dialog will open. When the Double Click Runs Interactive Properties option is enabled, the Properties panel will open.
While the options are the same in the dialog and the panel, the order and placement of the options may differ slightly.
Press Ctrl+Q to toggle the units of measurement currently used in the dialog/panel between metric (mm) and imperial (mil). This only affects the display of measurements in the dialog/panel; it does not change the measurement unit specified for the board, which is configured in the Units setting in the Properties panel when there are no objects selected in the design space.
The Leader Dimension properties can be accessed prior to entering placement mode, from the PCB Editor – Defaults page of the Preferences dialog. This allows the default properties for the Leader Dimension object to be changed, which will be applied when placing subsequent Leader Dimensions.

Editing Multiple Objects

The Properties panel supports editing multiple objects, where the property settings that are identical in all currently selected objects may be modified. When multiples of the same object type are selected manually, via the Find Similar Objects dialog or through a Filter or List panel, a Properties panel field entry can be edited for all selected objects. If values of a property are different for objects in the selection, the appropriate field will be shown as an asterisk (*) – a new property value will be applied to all selected objects.

Editing via a List Panel

Panel pages: PCB List, PCB Filter, PCBLIB List, PCBLIB Filter

A List panel allows you to display design objects from one or more documents in tabular format, enabling quick inspection and modification of object attributes. Used in conjunction with appropriate filtering – by using the applicable Filter panel, or the Find Similar Objects dialog – it enables the display of just those objects falling under the scope of the active filter – allowing you to target and edit multiple design objects with greater accuracy and efficiency.


  • A leader dimension object can be moved in the following ways:
    • Select both the dimension object and the object that is being dimensioned: the whole can be dragged to a new location as required.
    • Select the object that is being dimensioned only: the dimension will follow the object. The segment of the leader dimension (between the arrow/dot and the first defined elbow) will expand/contract to keep the relationship between the dimension and the object being dimensioned.
    • Select the dimension object only: it is important to note that the dimension cannot be moved on its own if it is referenced by a design object. To move the dimension only, it must first be detached from the object it is dimensioning.
  • When the reference to which a dimension object is attached is deleted, a dialog will open asking whether the dimension should also be deleted. If the dimension is not deleted, it remains in the design space but non-referenced.
  • Leader dimensions are group objects consisting of text and track segments. They can be converted to their set of primitive objects by choosing Tools » Convert » Explode Dimension to Free Primitives from the main menus. Once exploded, a dimension object can no longer be manipulated as a group object.
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