Typically, the pediment forms the end of a gabled roof or defines the main point of entry into a classical building. As a result, the pediment is symbolically and functionally an important part of classical architecture.
The pediment comprises two inclined, or raking, cornices and a horizontal cornice which defines a triangular area known as the tympanum. In the following plate, the juncture between the raking cornice and horizontal cornice is illustrated. The cymatium crowns the raking cornice but is omitted from the horizontal cornice of the pediment. A split fillet provides a small but important visual connector between these two elements.
Because the raking cymatium is set at an angle, it is slightly larger and has a different profile from the horizontal cymatium at the returns. To determine the profile of the raking cymatium, divide its curved portion into 6 equal parts as indicated by the dashed lines. At the point where each dashed inclined line meets the profile of the horizontal cornice, project each point vertically upward to line A-B. Since the raking cymatium and horizontal cornice meet at a 45 degree angle, line A-B also represents the projection of the raking cymatium. This line can be drawn parallel to the rake so that lines projecting down at a 90 degree angle will define the profile of the raking cymatium where they meet the inclined dashed lines.
Below the raking cymatium is the raking fillet (part of the split fillet) which has the same width as the horizontal cornice. Likewise, the raking corona and raking bed mold have the same width and projection from the frieze as their horizontal counter parts. The tympanum is in the same plane as the frieze.
Text: Martin Brandwein Rendering: M. Gunnison Collins