Working with a Sawtooth Object on a PCB in Altium Designer

Parent page: PCB Design Objects

Sawtooth objects are added to increase the length of a route, the Net Length Gauge indicates the progress towards achieving the required target length.

Summary

The sawtooth object is a system-created group object. The sawtooth object is created by the software during interactive length tuning to increase the overall length of a route. The software builds the sawtooth-shaped section of routing from tracks and/or arcs in accordance with the properties defined in the sawtooth mode of the Properties panel. Because the sawtooth object is a group object, a placed sawtooth can be interactively reshaped if required.

Availability

The sawtooth object is placed automatically in the PCB editor when the Interactive Length Tuning command is being used and the route length is shorter than the length specified for that net.

The route length requirement is specified by:

• An applicable Length design rule.
• An applicable Matched Length design rule.
• A user-defined length, specified in the Sawtooth mode of the Properties panel or Sawtooth dialog.

Placement

After launching the PCB editor's Route » Interactive Length Tuning command, the cursor will change to a cross-hair and you will enter length tuning (Sawtooth placement) mode. Placement is made by performing the following sequence of actions:

1. Click on the routed net that needs its length to be increased.
2. Move the cursor along the route in the direction that the sawtooth is to be added as shown in the animation above. A sawtooth will appear and continue to grow as the cursor moves. The sawtooth properties (length, style, amplitude, and gap) will be in accordance with the current settings defined in the Sawtooth mode of the Properties panel (more on this below). The amplitude of the sawtooth is automatically decreased to avoid existing routing and component objects as shown in the image at the top of this page.
3. During placement, the cursor can move away from the existing route by up to the current Max Amplitude distance specified in the Properties panel. If the cursor moves further than this, the sawtooth currently being placed will disappear. Move the cursor back towards the existing route to restore the sawtooth being placed.
4. The sawtooth will stop growing when the required overall route length is achieved if the Clip to Target option is enabled in the Properties panel. Click to complete placement of the sawtooth.
5. Continue tuning other route lengths (placing further sawteeth) or right-click or press Esc to exit length tuning mode.

Additional actions that can be performed during placement include:

• Press the Tab key to pause placement and access the Sawtooth mode of the Properties panel from where its properties can be changed on-the-fly. Click the pause button overlay ( ) to resume placement.
• The properties of the sawtooth can also be interactively adjusted during placement using shortcuts. Refer to the Placement Shortcuts section to learn more about the shortcuts.

Placement Shortcuts

The shortcuts available during length tuning include:

Graphical Editing

This method of editing allows you to select a placed Sawtooth object directly in the design space and graphically change its size and shape.

Sawtooth tuning pattern supports the  and shortcut keys to interactively decrease/increase the height of the tuning pattern during placement.

When a Sawtooth object is selected, its polygonal outline is displayed as shown in the animation below. The outer shape of the polygonal outline is defined by a series of edges: where each edge is represented by an end vertex at each end. Each end vertex represents the location where two edges meet.

Standard polygonal shape editing techniques are available for editing the shape.

When editing a polygonal object, there are three editing modes available, Slide/Miter, Incurvate (arc), and Move. The current mode can be changed while dragging a vertex or an edge by pressing Shift+Spacebar to cycle through the three modes.

• Slide/Miter - click and hold on an edge or a center vertex to slide that edge; click and hold on an end vertex to miter the corner.
• Incurvate - click and hold on an edge or a center vertex to incurvate that edge; click and hold on an end vertex to incurvate (arc miter) the corner.
• Move - click and hold on an edge or a center vertex to break that edge into two edges; click and hold on an end vertex to freely move that corner.

Non-Graphical Editing

The following methods of non-graphical editing are available.

Editing via the Sawtooth Dialog or Properties Panel

Properties page: Sawtooth Properties

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

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

During interactive length tuning, the Properties panel can be accessed by pressing the Tab key.

After placement, the Sawtooth dialog can be accessed by:

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

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

• If the Properties panel is already active, select the Sawtooth object.
• After selecting the Sawtooth 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.

The properties displayed in the panel and dialog reflect the settings that were used to create the selected sawtooth.

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 page: PCB List, PCB 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.