Two bottom layer Keepout Arcs: on the left is a Full Circle Keepout Arc; on the right
is a Keepout Arc selected for editing.
An arc is a primitive design object. It is essentially a circular track segment that can be placed on any layer. As well as the standard arc that is used for design tasks such as defining a component outline or curved routing, there is a second type of arc available, referred to as a keepout arc. A keepout arc can be placed on a signal layer to create a layer-specific barrier or no-go region. They also can be placed on the Keepout layer where they will apply to all signal layers. The difference between a standard arc and a keepout arc is that layer-specific keepout-type arcs are not included in output generation, such as Gerber or ODB++. A keepout arc is identified by having an outline in the Keepout color.
Keepout Arcs are available for placement in both PCB and PCB Library Editors. There are four keepout arc placement modes available (Center, Edge, Any Angle, and Full Circle). The modes are described in the Placement section.
PCB Editor - to place a keepout arc:
Choose the required keepout arc mode from the Place » Keepout submenu, or
Choose the Arc (Center) mode from the PCB Editor Active Bar. The keepout objects are accessed via the keepout button on the bar (as shown below), click and hold anywhere on that button to access all keepout objects. The last used menu button will become the current Active Bar button.
PCB Library Editor - to place a keepout arc:
Choose the required standard arc mode from the Place » Keepout submenu, or
Choose the Arc (Center) mode from the PCB Library Editor Active Bar. The keepout objects are accessed via the keepout button on the bar (as shown below), click and hold anywhere on that button to access all keepout objects. The last used menu button will become the current Active Bar button.
A keepout arc can only be placed on a signal layer or the Keepout layer.
The way in which an arc is placed depends on the particular method of placement that you have chosen to invoke. Four different methods of arc placement are supported:
Place arc by center – this method enables you to place an arc object using the arc center as the starting point.
Place arc by edge – this method enables you to place an arc object using the edge of the arc as the starting point. The arc angle is fixed at 90°.
Place arc by edge (any angle) – this method enables you to place an arc object using the edge of the arc as the starting point. The angle of the arc can be any value.
Place full circle arc – this method enables you to place a 360° (full circle) arc.
After launching the command, the cursor will change to a crosshair and you will enter arc placement mode. Placement is made by performing the following sequence of actions:
Click or press Enter to anchor the center point of the arc.
Move the cursor to adjust the radius of the arc then click or press Enter to set it and complete placement of the arc.
Continue placing further arcs or right-click or press Esc to exit placement mode.
Additional Placement Actions
Additional actions that can be performed during placement are:
For all methods (excluding full circle arcs), press the Spacebar before defining the arc's end point to render the arc in the opposite direction.
Press the L key to flip the arc to the other side of the board – note that this is possible only prior to anchoring the arc's start/center point.
Press the + and - keys (on the numeric keypad) or use the Shift+Ctrl+Wheelroll shortcuts to cycle forward and backward through all visible layers in the design to change placement layer quickly.
Press the Tab key to open the Keepout - Arc mode of the Properties panel from where properties for the arc can be changed on the fly. When this is done interactive editing will pause so that the panel can be used, click the button to return to the interactive arc placement mode or press Esc.
While attributes can be modified during placement (Tab to open the 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.
This method of editing allows you to select a placed arc object directly in the design space and graphically change its size, shape or location.
When a keepout arc object is selected, the following editing handles are available:
Click and drag A to adjust the radius.
Click and drag B to adjust the end points (start and end angles).
Click anywhere on the arc away from editing handles then drag to reposition it. Alternatively, click and drag on the arc center-point. While dragging, the arc can be rotated or mirrored:
Press the Spacebar to rotate the arc 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 arc along the X-axis or Y-axis respectively.
If attempting to graphically modify an object that has its Locked property enabled ( button in the Properties panel), 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 selected or graphically edited. Click the locked object to select it then disable the Locked property in the List panel or disable the Protect Locked Objects option to graphically edit the object.
The following methods of non-graphical editing are available:
This method of editing uses the associated Keepout - Arc dialog mode and Properties panel to modify the properties of an Arc Keepout object.
The Keepout - Arc dialog on the left, and the Keepout - Arc mode of the Properties panel, on right
During placement, the Keepout - Arc mode of the Properties panel can be accessed by pressing the Tab key. Once the Arc Keepout is placed, all options appear.
After placement, the KeepoutArc dialog can be accessed by:
Double-clicking on the placed Arc Keepout object.
Placing the cursor over the Arc Keepout object, right-clicking then choosing Properties from the context menu.
After placement, the Keepout - Arc mode of the Properties panel can be accessed in one of the following ways:
If the Properties panel is already active, by selecting the Arc Keepout object.
Right-click select the Properties panel from the Panels button in the bottom right section of the design space, or by selecting View » Panels » Properties from the main menu.
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 panel between metric (mm) and imperial (mil). This only affects the display of measurements in the 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 editing design space.
The 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.