In our perspective drawing above, you can see the lines of construction used to draw the two rectangles from our illustration on page 2.

There are two types of construction lines used in perspective drawing:

1) Orthogonal Lines which we have drawn in red.

2) Transversal Lines which we have drawn in green.

We will continue to use this colour coding in subsequent illustrations.

Orthogonal Lines

Orthogonal lines are parallel to the ground plane and move back from the picture plane.

Orthogonal lines set the varying heights or widths of a rectangular plane as it recedes from view.

Orthogonal lines always appear to meet at a vanishing point on the eye level.

Transversal Lines

Transversal lines are always at right angles to the orthogonals.

Transversal lines are parallel to the picture plane and to one another.

Transversal lines establish a fixed height or width between two orthogonal lines.

Transversal lines form the nearest and furthest edges of a rectangle as it recedes from view.

Vanishing Points

Vanishing points, which we have drawn in blue, are dots on the eye-level where parallel lines seem to converge and disappear.

Our illustration uses a single vanishing point and is the simplest form of perspective drawing.

It is an example of One Point Perspective.