Aliasing refers to the jagged edges and other rendering artifacts commonly associated with computer-generated drawings. It is caused by the presence of higher frequency renderings than can be represented by the pixel samples. Lines are much more susceptible to aliasing problems because every pixel drawn is part of an edge while most pixels of polygon models are in the middle where there are no high frequencies. More detailed explanations of why this is so are available in [71], [72], [62], and [21].