Working with an Arc Object on a Schematic Sheet in Altium Designer

Parent page: Schematic Objects

Two placed Arcs (the one on the right is a Full Circle Arc).

Summary

An arc is a non-electrical drawing primitive. It is essentially a curved line segment which can be used when, for example, creating graphical symbols, custom sheet borders and title blocks.

Availability

Arcs are available for placement in both Schematic and Schematic Library Editors:

• Schematic Editor - the following commands are available:
  • Choose Place » Drawing Tools » Arc from the main menus, to place an arc with full control over start and end angles.
  • Choose Place » Drawing Tools » Full Circle from the main menus, to place a full circle arc, where start and end angles are fixed at 0 and 360 Degrees respectively.
  • Right-click and choose Place » Drawing Tools » Arc or Place » Drawing Tools » Full Circle from the context menu.
• Schematic Library Editor - the following commands are available:
  • Choose Place » Arc from the main menus, to place an arc with full control over start and end angles.
  • Choose Place » Full Circle from the main menus, to place a full circle arc, where start and end angles are fixed at 0 and 360 Degrees respectively.
  • Right-click and choose Place » Arc or Place » Full Circle from the context menu.

Placement

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

1. Click or press Enter to anchor the center point of the arc.
2. Move the cursor to adjust the radius of the arc, then click or press Enter to set it.
3. Move the cursor to adjust the start angle for the arc, then click or press Enter to anchor it.
4. Move the cursor to adjust the end angle for the arc, then click or press Enter to anchor it and complete placement of the arc.
5. Continue placing further arcs, or right-click or press Esc to exit placement mode.

Additional actions that can be performed during placement – while the arc is still floating on the cursor, and before the center point of the arc is anchored – are:

• Press the Tab key to access an associated properties dialog, from where properties for the arc can be changed on-the-fly.
• Press the Alt key to constrain the direction of movement to the horizontal or vertical axis, depending on the initial direction of movement.
• Press the Spacebar to rotate the arc anti-clockwise or Shift+Spacebar for clockwise rotation. Rotation is in steps of 90°.
• Press the X or Y keys to mirror the arc along the X-axis or Y-axis respectively.

Graphical Editing

This method of editing allows you to select a placed arc object directly in the workspace and change its size, shape or location, graphically.

When an arc object is selected, the following editing handles are available:

Selected Arcs (Full Circle Arc on right).

• 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 – and drag to reposition it. While dragging, the arc can be rotated (Spacebar/Shift+Spacebar) or mirrored (X or Y keys to mirror along the X-axis or Y-axis respectively).

Non-Graphical Editing

The following methods of non-graphical editing are available:

Via an Associated Properties Dialog

Dialog page: Arc

This method of editing uses the Arc dialog to modify the properties of an arc object.

The Arc dialog.

The Arc dialog can be accessed prior to entering placement mode, from the Schematic – Default Primitives page of the Preferences dialog. This allows the default properties for the arc object to be changed, which will be applied when placing subsequent arcs.

During placement, the dialog can be accessed by pressing the Tab key.

After placement, the dialog can be accessed in one of the following ways:

• Double-clicking on the placed arc object.
• Placing the cursor over the arc object, right-clicking and choosing Properties from the context menu.
• Using the Edit » Change command and clicking once over the placed arc object.

Via an Inspector Panel

Panel pages: SCH Inspector, SCHLIB Inspector, SCH Filter, SCHLIB Filter

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 - by using the applicable Filter panel, or the Find Similar Objects dialog - the panel can be used to make changes to multiple objects of the same kind, from one convenient location.

Via a List Panel

Panel pages: SCH List, SCHLIB List, SCH Filter, SCHLIB Filter

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 - 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 the designer to target and edit multiple design objects with greater accuracy and efficiency.