EAGLE Guided Tour Part 14: Copper Pouring

Creating copper areas is done with the Polygon command. It allows you to draw the outlines of an area and assign it to a specific signal. The Ratsnest command then calculates the exact shape of the copper area. Unlike other programs which implement copper pouring by subtracting layers from each other, EAGLE actually calculates the entire shape of the area. It therefore can detect orphaned areas (which are not connected to the signal, like in the lower right corner of the example).