PCB Footprint

Electronic components typically have a 'Footprint', sometimes called a 'Decal' or 'Land Pattern' which specifies the 2D geometry of how the component is soldered to the printed circuit board.

Altium has a pretty nice workflow

http://www.accelerated-designs.com/(S(jlmltf45uft1olu50frefkvw))/Demo.aspx

Altium workflow

A footprint thus typically comprises of 3 or 4 layers of simple vector 2D vector shapes.