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Starting Out: Car Design Glossary - Part 2
by David Browne, Director Automotive Design, Coventry University   
Original Renault Twingo (and also Fiat's Cinquecento) has soft curves, generous radii, a happy face and 'playful' interior detailing. Original Audi TT (below right) highly disciplined 'geometric' surfaces and detailing. Ford Ka (bottom left) graphic was named 'New Edge'

Form Language

(See also surface language)

This can refer to the manipulation of the form of any individual vehicle, or to the visual 'feel' or identity that characterizes and unites a manufacturer's entire range. It can also refer to the 'library' of design themes, manners, details, clichés, etc., available for a designers reference.

Usually, the way the principle surfaces of any car's exterior - and interior - are treated will help to confirm its nature or purpose. A small city car, intended to be non-threatening and friendly, may have soft curves, generous radii, a happy face and 'playful' interior detailing. Sportscars' surfaces should help make them look athletic and powerful, and 4x4's will tend to be chunky and apparently unsubtle and unrefined.

Deployed corporately, surface language is a form of brand or marque identity, referring to the manner in which designers from different companies will treat the sculptural journey from broadly similar points 'A' to points 'B'.

Audi designs, for example - epitomized by the original TT - have highly disciplined 'geometric' surfaces and detailing: perfect radii, incised shutlines and precise surfacing. This 'cerebral' designing characterizes the whole range and creates a unified family identity (interestingly, the 'organized' surfaces of an Audi-designed Lamborghini couldn't be mistaken for the more ‘seductive' sculpture of a Ferrari).

'Jaguarness' can be traced backwards (side-stepping the XJ-S....) to the emotive E-Type, D-Type and C-Type, but the sharper new XF attempts to redefine the new way forward.

Some form language is even afforded the significance of being named: Ford's graphic 'New Edge' of the 1990s and less convincing moving-when-standing-still 'Kinetic Design' (illus. Fiesta, bottom right). BMW's controversial 'flame surfacing' unifies their entire, diverse, range.

Some early Japanese, and more recently Korean and Chinese manufacturers, with no design history of their own, have ‘borrowed' others' successful design language as a shortcut to market acceptance. 


French Curves

Guides used to describe curves of varying radii - i.e. non-constant curves which produce lines which 'accelerate' or 'speed up' by 'unwinding' - are called French Curves and Ships Curves. These are templates made from plastic, wood or metal used to create smooth curves between two or more pre-determined fixed points in both 2D drawing and 3D manual modeling.

French Curves are the small, multi-sided, transparent plastic templates made from combinations of different external, and 'pierced' internal, curves. The ubiquitous standards are the Burmester set (of 3) and those appropriately known as Ram's Horns (or Monkey Tails in the US).

Ships Curves are generally larger, altogether simpler, without internal cut-out shapes, and useful for longer, more 'relaxed' lines.

Railway Curves or Sweeps (sometimes called 'Steels') have constant radii - i.e. their curvature is the same at any point along their length. They come in graduated sets in both clear plastic for drawing and small-scale modeling, and in steel or aluminum for full-size clay modeling purposes.

Ellipse Guides or Templates are used for drawing wheels in perspective and come in a range of angles from an acute 15 to an almost round 80 degrees, and like Circle Guides seem to be almost universally produced in translucent green plastic.

Fiat 520 sedan (1927-29) is an early 'six-light '; Audi A4 (below) is a more recent example. Volkswagen Passat CC is a 'four light' design


Not, as you might think, something you switch on when it gets dark, but the traditional name for car windows. Hence from the 1920's, a 'six light' sedan is one with three separate side windows on each side.

As an example, an Audi A4 is a 'six light' design, whereas a VW Passat CC is a 'four light' design, even though both have a similar elongated DLO graphic.

The rear window of a car is variously referred to as the 'rear screen', 'back light' or 'rear light'.

See also Day Light Opening (DLO)

Nissan Rogue conceals Mohican lines below roof rails
Mohican Line

This is a good example of the continuously developing vocabulary of the designer.

It refers to the black or body-colored capping strips which run lengthwise along the sides of the roof and serve the dual purpose of hiding a major weld line where the body-side pressing meets the roof panel, and concealing location points for roof racks. So cars have not one, but two, Mohican lines.

Developed in the early 80s by Japanese companies, these replaced conventional seam-concealing tacked-on roof gutters, reducing visual clutter and cost. It's a Japanese studio-derived term largely unknown in American or European studios - whose 'roof joint finisher' or 'roof channel capping' sound rather dull by comparison.

1923 Lancia Lambda was pioneer of the monocoque. McLaren F1 (below left) and Ferrari Enzo (right) are modern examples
Monocoque (sometimes ‘Unibody’)

This is a construction method - first widely used by the aircraft industry - in which the exterior stressed skin panels support some or all of the loads on the structure. Most cars are made this way.

Pioneered by Lancia with the 1923 Lambda, the first truly mass-produced chassis-less European monocoque was the 1934 American Budd-inspired Citroen ‘Traction Avant'.

In 1946, aircraft manufacturers Piaggio devised a unique two-wheeled utility vehicle using structural steel pressings. The Vespa scooter mobilized post-World War II Italy, and became both design classic and legend.

Oddly, this is a construction method that operates at both ends of a scale: in steel it's suited to high production numbers, but in carbon fiber it's used in small production runs of extremely expensive cars such as the Ferrari Enzo and McLaren F1.


1960 Maserati T.60 'Birdcage'

This is a construction method in which a complex but lightweight and rigid, internal structure or skeleton is covered by a non load-bearing skin. This building method lends itself to cheaper and more noticeable facelift exercises.