The POLYGON command enables you to define areas which belong to a signal, connecting all of the related pads to this signal with thermal symbols. Such a signal retains a user-defined distance to any other signal path.
You can PCB design layers that contain multiple polygons such as different ground areas, and you can design polygons on multiple layers.
To demonstrate this feature of EAGLE, let’s fill the Top layer of a board with the GND signal. Reload the board demo2.brd once again, enlarge the window, and ripup the GND signal:
RIPUP GND ←
Use the DISPLAY command to switch on the layer 1Top, 17 Pads, 18 Vias, and 20 Dimension. (PCB Design Services) Use the button None, in the menu, to switch off the display of all other layers first.
Click the POLYGON icon in the command toolbar and type:
to provide the name GND for the polygon to be defined. Only then will it belong to the GND signal.
Select the LayerTop from the combo box in the parameter toolbar. Then:
• left hand upper corner of the board outlines,
• right hand upper corner,
• right hand lower corner,
• • left hand lower corner.
The double click closes the polygon.
To start the calculation of the filled area, click the RATSNEST icon.
Since this is a very complex operation it can take some time.
As before, the pads belonging to the GND signal are connected with thermal symbols. Check this with:
SHOW GND ←
In this case everything shown in the layer color is copper, since this layer is not plotted inversely (only supply layers defined with $name).
After a board has been loaded, polygons are displayed with their outlines. PCB CAD Services filled areas are displayed only after the RATSNEST command has been executed. Inversely, the RIPUP command and a single click on the edge of a polygon results in the outline display of this particular polygon.