The artist drawing a scene faces the choice of a number of possibilities regarding vantage point and position of the picture plane. These choices naturally determine the way the artist sees the scene; for instance, whether a subject is portrayed frontwards, or side face, or somehow in between. It is apparent that the number of substantially different choices for our artist depends on, and increases with the complexity of, the scene. Since the nature of this scene is not necessarily amenable to mathematical terms, the idea of a catalogue of such choices akin to the catalogues we described in Section 3.8 is out of place. But there are a number of choices having a mathematical character which can be considered independently of the depicted scene.