 This transformation puts the objects into normalized device coordinates.More concretely, a point in clip coordinates is represented with four components,

and the following equality defines the relationship between the normalized device coordinates formula_4, formula_5 and formula_6 and clip coordinates,

Clip coordinates are convenient for clipping algorithms as points can be checked if their coordinates are outside of the viewing volume.For example, a coordinate formula_8 for a point is within the viewing volume if it satisfies the inequality formula_9.