Working with a Region Object on a PCB in Altium Designer

Parent page: PCB Objects

Examples of the various types of placed region objects.

Summary

A Region, also known as a Solid Region, is a polygonal-shaped primitive object that can be placed on any layer. It can be configured to be positive, for example placed as a copper region; or negative, for example placed as a polygon pour cutout. By placing it as a negative on the multi-layer, it can be placed as a board cutout.

A region can have any number of sides and vertices (corners). It can be placed on a signal layer to define an area of solid copper, to be used to provide shielding or to carry large currents. Positive regions can be combined with tracks or arc segments and be connected to a net. In the PCB Library editor regions can be used to create custom pad shapes on copper layers, or special mask shapes on the solder and paste masks. On non-electrical layers regions can be used to define custom shapes for tasks such as logos.

A region can also be used to define no-go areas for component placement and routing, which are also known as keep-outs. These can apply to all layers by placing the region on the Keep-out layer, or they can be layer-specific by placing the region on a signal layer and enabling the Keep-out option for that region.

When placed as a negative, a region can create a cutout (a void) in a polygon pour. In this mode the region will not be filled with copper when the polygon is poured. When used as a negative region for a board cutout (by placing it on the multi-layer), it defines an area that becomes a hole through the finished board. Board cutout regions are transferred to Gerber and ODB++ files for manufacturing purposes.

Availability

Regions are available for placement in both the PCB editor and the PCB Library editors by selecting Place » Solid Region or Place » Keepout » Solid Region from the main menu.

Placement

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

1. Position the cursor and click to anchor the starting vertex for the region.
2. Move the cursor ready to place the second vertex. The default behavior is to place 2 edges with each click, with a user-defined corner shape between them. Refer to the Placement Modes topic below for more details on changing corner modes.
3. Continue to move the mouse and click to place further vertices.
4. After placing the final vertex, right-click or press Esc to close and complete placement of the region. There is no need to manually close the region as the software will automatically complete the shape by connecting the start point to the final point placed.
5. Continue placing further regions, or right-click or press Esc to exit placement mode.

Additional actions that can be performed during placement include:

• Press the + and - keys on the numeric keypad to cycle forward and backward through all layers currently visible in the design.
• Press the * key to cycle through the visible signal layers.
• Press the Tab key to access an associated properties dialog, from where properties for the region can be changed on-the-fly.

Placement Modes

While placing a region there are 5 available corner modes, 4 of which also have corner direction sub-modes. During placement:

• Press Shift+Spacebar to cycle through the 5 available corner modes: 45 degree, 45 degree with arc, 90 degree, 90 degree with arc, and Any Angle.
• Press Spacebar to toggle between the two corner direction sub-modes.
• When in either of the arc corner modes, hold the  or  keys to shrink or grow the arc. Hold the Shift key as you press to accelerate arc resizing.
• Press the 1 shortcut key to toggle between placing 2 edges per click, or one edge per click. In this second mode the dashed edge is referred to as the look-ahead segment (as shown in the last image in the set below).
• Press the Backspace key to remove the last vertex.

Press Shift+Spacebar to cycle through the 5 available corner modes, press the 1 shortcut to toggle placement between 2 edges or 1 edge.

Placing a Region as a Keepout

Using the Place » Keepout » Solid Region command, a region can be placed as a layer-specific keepout object or an all-layer keepout to act, for example, as a placement or routing barrier. Objects defined as keepouts are ignored during output generation, such as photo plotting and printing.

Keepout properties and restrictions can be assigned using the Keepout - Region dialog.

To access the Keepout - Region dialog, press Tab during placement. After placement, access the dialog by double-clicking on the Keepout Region or right-click and select Properties from the context menu.

Placing a Region as a Polygon Cutout

A Region can also act as a polygon cutout. To place a polygon cutout:

1. Place a standard region over the polygon and then enable the Polygon Cutout option in the dialog to achieve this.
2. Repour the polygon to pour around the new cutout using one of the Repour commands available in main menu at Tools » Polygon Pours.

Placing a Region as a Board Cutout

A Region can also act as a board cutout. To place a board cutout:

1. Place a standard region over the board shape and then edit the region and enable the Board Cutout option in the dialog to achieve this, or,
2. Place a board cutout directly via the menu at Design » Board Shape » Define Board Cutout.
3. Repour any polygons that overlay the board cutout using one of the Repour commands available on the menu at Tools » Polygon Pours.

Graphical Editing

Move Region Vertices

Regions contain to points, or "handles" with which to edit the shape of the region.

1. Full Handles - These filled handles are located at the corners of the region.
2. Empty Handles - These blank handles are located in the centers of the segments created by the Full Handles.

An existing region can be re-shaped by moving these handles, or vertices, located at each corner, or at the center of each edge.

To modify the region shape:

1. Click and select a region, which will highlight the vertices for the region and change the cursor to a crosshair.
   1. Click on a Full Handle to move that corner.
   2. Click along an edge to move the entire edge.
   3. Click on an Empty Handle to move the whole side (for track and for arc).
   4. Ctrl+Click on an Empty Handle to break that edge into 2 edges. Ctrl only needs to be held at the beginning of movement. The Shift+Spacebar hotkeys can then be used to cycle through modes (arc, miter, and any angle).
      

 
The various methods of moving region vertices.

2. If the any angle placement mode creates unwanted vertices, or to remove extra vertices in general, click Ctrl and grab the central full handle. An X icon appears over the handle and dragging the edge will reduce the vertices on that edge to one.

Modify Region Border

In addition to vertex editing, designers can also use the Modify Region Border command to easily change the shape of polygons. The command is run by right-clicking on the desired polygon and selecting Polygon Actions » Modify Polygon Border. Once the command is launched, the cursor becomes a crosshair. Each time you click, a new vertex is added. As during region placement, the Shift+Spacebar shortcuts can be used to change corner shapes.

 
Modifying a region border.

Non-Graphical Editing

The following methods of non-graphical editing are available:

Editing via an Associated Properties Dialog

Dialog page: Region

This method of editing uses the following dialog to modify the properties of a region object.

The Region 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 region object.
• Placing the cursor over the region object, right-clicking and choosing Properties from the context menu.

When editing a Polygon Cutout via the Region dialog, the only properties available for editing are Layer an Vertices.

Editing via an Inspector Panel

Panel pages: PCB Inspector, PCBLIB Inspector

An 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.

Editing via a List Panel

Panel pages: PCB List, PCBLIB List

A List panel allows the designer 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, it enables the display of just those objects falling under the scope of the active filter – allowing the designer to target and edit multiple design objects with greater accuracy and efficiency.