EAGLE Help

# ARC

Function
Draw an arc of variable diameter, width, and length.

Syntax
ARC ['signal_name'] [CW | CCW] [ROUND | FLAT] [width] * * *

Mouse
Center button changes the active layer.
Right button changes the orientation.

The ARC command, followed by three mouse clicks on a drawing, draws an arc of defined width. The first point defines a point on a circle, the second its diameter. Entering the second coordinate reduces the circle to a semi-circle, while the right button alters the direction from first to second point. Entry of a third coordinate truncates the semi-circle to an arc extending to a point defined by the intersection of the circumference and a line between the third point and the arc center.

The parameters CW and CCW enable you to define the direction of the arc (clockwise or counterclockwise). ROUND and FLAT define whether the arc endings are round or flat, respectively (please note that for performance reasons "round" endings are approximated by "half octagons" on some output devices, as is also the case with Wires).

Signal name

The signal_name parameter is intended mainly to be used in script files that read in generated data. If a signal_name is given, the arc will be added to that signal and no automatic checks will be performed.
This feature should be used with great care because it could result in short circuits if an arc is placed in a way that it would connect different signals. Please run a Design Rule Check after using the ARC command with the signal_name parameter!

Line Width

The parameter "width" defines the thickness of the drawn line. It can be changed or predefined with the command:

```CHANGE WIDTH width;
```
The adjusted width is identical to the line width for wires.

Arcs with angles of 0 or 360 degrees or a radius of 0 are not accepted.

Example for text input:

```GRID inch 1;
ARC CW (0 1) (0 -1) (1 0);
```
generates a 90-degree arc with the center at the origin.