The section

The section works in the vertical plane as does the elevation, but with one important difference. A section can be placed at any distance away from the wall that is the subject of the drawing, thus including or excluding features at will. In fact, the cut does not even need to be a single planar cut through the space; it can jump from plane to plane, varying in distance from the subject wall, but remaining parallel to it. Like the elevation, there should be no perspective, but unlike the elevation, the structure enclosing the space is shown at the point where the section cut dissects it, so wall thicknesses and so on are indicated.

Shown here is a quick section sketch by Emily Pitt for the design of a house in Notting Hill, England. Colour has been used to show use: green for guest areas and blue for occupant areas.