Center Dimension
Contents
Parent page: Dimension
A placed Center Dimension.
Summary
A center dimension is a group design object. It allows for the center of an arc or circle to be marked.
Availability
Center dimension objects are available for placement in the PCB Editor only, by clicking Home | Dimension | 
and selecting Center from the drop-down list.
Placement
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:
- Position the cursor and click or press Enter to anchor the dimension to the desired arc or circle.
- Move the dimension until the desired sizing is achieved then click or press Enter to complete placement.
- Continue placing further center dimensions, or right-click or press Esc to exit placement mode.
Additional actions that can be performed during placement are:
- Press the + and - keys (on the numeric keypad) to cycle forward and backward through all visible layers in the design respectively – to change placement layer quickly.
- Press Spacebar to rotate the dimension anti-clockwise 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 Tab key to access an associated properties dialog, from where properties for the dimension can be changed on-the-fly.
Graphical Editing
This method of editing allows you to select a placed center dimension object directly in the workspace and change its size and orientation, graphically.
When an center dimension object is selected, the following editing handles are available:
A selected Center Dimension.
- Click & drag A to change the size of the dimension. As you drag a handle, the dimension may be rotated (Spacebar/Shift+Spacebar).
Non-Graphical Editing
The following methods of non-graphical editing are available:
Via an Associated Properties Dialog
Dialog page: Center Dimension
This method of editing uses the following dialog to modify the properties of a center dimension object.
The Center Dimension dialog.
The Center Dimension dialog can be accessed during placement by pressing the Tab key.
After placement, the dialog can be accessed in one of the following ways:
- Double-clicking on the placed center dimension object.
- Placing the cursor over the center dimension object, right-clicking and choosing Properties from the context menu.
Quickly change the units of measurement currently used in the dialog between metric (mm) and imperial (mil) using the Ctrl+Q shortcut. This affects the dialog only and does not change the actual measurement unit employed for the board, as determined by the 
and buttons in the Home | Grids and Units area of the main menus.
Via the PCB Inspector Panel
Panel page: PCB Inspector
The PCB Inspector panel enables the designer to interrogate and edit the properties of one or more design objects in the active document. Used in conjunction with appropriate filtering, the panel can be used to make changes to multiple objects of the same kind, from one convenient location.
Notes
- A center dimension object can be moved in the following ways:
- Selecting both the dimension object and the circle/arc that is being dimensioned. The whole can be dragged to a new location as required.
- Selecting the circle/arc that is being dimensioned only. The dimension will move with the object.
- When the reference arc or circle to which a center dimension object is attached is deleted, a dialog will appear, asking whether the dimension should also be deleted. If the dimension is not deleted, it remains in the workspace, but non-referenced. Note however that a non-referenced center dimension cannot be attached to another circle/arc.