Laws of perspective

The essential idea of perspective is that light rays from a scene form a cone (known as a projection) to the eye through an imaginary screen or window (the picture plane). The set of points where the rays meet the screen constitute a picture or section, the appearance of which is determined by laws of perspective, some of which are given below:

• For lines parallel to the picture plane (PP), vertical lines are drawn as vertical, and horizontal lines are drawn as horizontal.

• For lines inclined to the picture plane,
parallel lines meet at a vanishing point (VP),
lines perpendicular to the picture plane vanish at a point called the centre of vision (CV)
on the horizon line (HL) directly in front of the eye.
horizontal parallel lines vanish at a point on the horizon.
horizontal lines at 45° to the picture plane meet at the diagonal vanishing point, (DVP),
a point on the horizon equal in distance from the centre of the eye.

Types:
One point perspective     Two point perspective     Three point perspective