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Starting Out: Car Design Glossary - Part 1
by David Browne, Director Automotive Design, Coventry University   
1987 Chrysler Portofino concept (above). 1998 Dodge Intrepid ESX II (below left). 1993 Dodge Intrepid (below right)
 

Cab Forward

Chrysler's marketing department is credited with coining this one to describe their 1987 'Portofino' Concept Car,  though some say it was Ford design Vice President, Jack Telnac.  Railway enthusiasts however, will recognise the term from Southern Pacific's Cab Forward locomotives of the early 1900s.

The overwhelmingly positive reception for the Portofino, plus the instincts of a then fairly desperate Chrysler management team, led to the production of a stunning family of cab forward products: the 1993 Dodge Intrepid and the 1994 Chrysler LH and New Yorker which made even the once trend-setting, but admittedly ageing, Ford Taurus (Scorpio) look pretty dull.  These cars also heralded the resurgence of Chrysler as an automotive design force.

The benefit to the overall package was space: by moving the screen, driver and passenger forward, space was liberated for the rear compartment, and this was further enhanced by moving the (non-driven) rear wheels, and therefore wheel arch intrusion, backwards.  One way and another, it was a pretty innovative package & style combination - particularly in the context of full-sized American cars. 

At the other end of a theoretical cab position scale, you would have to put the hugely 'cab rearward' slingshot Mercedes-Benz SLR McLaren.

Mercedes-Benz C-Class (above), Citroen Pluriel (below left), Smart RoadsterCoupe (below right)
 

Cant Rail

The structural member which usually sits squarely on top of the B-pillar forming the top edge of the door frame aperture, and which may run (visually) seamlessly into the A and C pillars, an arrangement most clearly defined by glass-roofed versions of cars such as the Mercedes C-Class (illus).

Side curtain airbags are located on the inside of cantrails.

The Citroen Pluriel and Smart Roadster have removable Cant Rails.

A character line gives both definition and personality to a car
 

Character Line

An important feature line or crease which may be sculpted, or more pleasingly, created by the meeting of 2 planes on a car's surface, and which gives or adds both definition and 'personality' to the form.

A character line is more fundamental to, and therefore more important to a design than a feature line or a crease, and in the best examples may be sufficiently unique to represent that car when abstracted  eg SEAT Altea. The slightly 'banana-ed' sculptural character line that echoes the beltline and sweeps the flanks of the Mercedes CLS is also present on the A-Class, B-Class, R-Class and, in indented form, the commercial Viano, so is also a major expression of current Mercedes form language.

By contrast, the more 'scribed' character line on the bodyside of the Jaguar S-Type, intended to recall the 1960's 3.4 and 3.8S, is unique to that model, and doesn't appear on any other Jaguar.

See: Surface language

Front cheater (above) and rear cheater with incorporated door handle (below right)
Cheater Panel

The small triangular, usually matt black-painted, surface at the base of the A-Pillar. It generally forms the leading edge of the side glass graphic - or DLO - on, or just ahead of, the front door, and which may usefully disguise sculptural 'uncertainties' in this awkward, but key, conjunction of 3 planes. For such a small item, its contribution is surprisingly important, as can be seen when it is not there. (illus: Fiat Punto)

Functionally, if in the door, it happily provides a natural platform for external rear-view mirrors and a useful channel for the front glass drop.

Rear Cheater

Again, a small, usually matt black-painted, triangular panel at the base of the trailing edge of the rear side window or in the rear quarter panel.  In the former, its function will be to create a shorter door glass, to provide a vertical channel, and to enable the window to be lowered  without obstruction from the door closing and locking mechanisms. 

Functional considerations aside, front and rear, designers will have attempted to create the illusion of a longer and more elegant DLO.

Also known as the 'Flag' in USA

Clay

Automotive Styling Clay is a dull brown, grainless, wax-based material, originally of US origin, used as a top, finishing surface for scale and full-size exterior and interior models. Although temperature-sensitive, unlike water-based ceramic clay, it doesn't dry out, and cannot be fired.

It is preheated in 1 kg billets in ovens to a working temperature of around 60 degrees C, at which it is very malleable, and is applied as a 25 mm or so skin over a structure called a 'buck' or 'armature'. When it cools to room temperature, it is then sculpted using a variety of hand tools or computer-controlled 3 and 5-axis milling machines.

The particular advantage of clay is that it can as easily be added to as subtracted from, and the finished product is, literally, seamless.

Dressed Clays

As clay is such a dull, lifeless material, clay models need a bit of help to be readable and properly understandable by the non-designers who may make choices and decisions based on what they're looking at - and what they think they see.

The simplest form of 'dressed' clay - whether small scale or full-size - is one in which the glass areas are 'blacked out'. This can be achieved quickly and easily using black masking tape, black paint, or more uniformly using Di-Noc.

The Audi A5 (above) has a pronounced crease line at the shoulder.
Toyota bbka
Crease Line

A crease is the pressed or folded line created by the meeting of two different planes or surfaces.

Unlike feature lines, a crease is integral to a design, and cannot simply be applied to a surface, but is commonly  the means of defining major surfaces and elevations. Ford's 'New Edge' design used creases (mainly) to graphically define the boundaries - or edges - of the various surfaces on the Ka, Cougar etc.

A crease may be positive or negative, but has more inherent 'integrity' than a feature line. However, a particularily strong or interesting crease in an otherwise simple surface might take on the importance of a character line.

Two very adjacent creases may 'conspire' to create a feature line: Giugiaro's 1974 Mk 1 Golf (illus) had relatively flat body sections with crisp, straight, and uniform - almost folded - feature lines, and was referred to by Ford's Design Director, Uwe Bahnsen, as coming from the 'Origami' school of styling.