Clockwise from top: BMW X6 alloy, Citroen CX, Minilite wheel, Bugatti Type 35, Subaru WRX gold alloys

 

Alloy Wheels

Racing-derived like their wire-wheeled predecessors, this is the generic name for any non pressed-steel, metal wheel - the single most important piece of automotive jewelry.

They are cast or forged in aluminum alloy, with a protective, usually silver-painted finish, which replaced the unsuccessful polished and lacquered treatment of the 70s (illus.Citroen CX). Darker paint finishes are sometimes selectively machined back to the bare metal to add contrasting 'sparkle', while brake dust can also add a little useful detail definition. The simple use of distinctive gold paint on the Subaru Impreza and Renault's Clio Williams, guaranteed instant recognition.

The importance of wheels to a car's appearance and stance is not lost on the manufacturers, who always list a range of larger-diameter optional-extra alloys, and also fuels an enormous aftermarket industry.

Landmark, timeless - and now ubiquitous - designs include Bugatti's beautiful 1924 'Type 35' (whose 8-spoke castings brilliantly incorporated the brake drums) and the 1960s 'Minilite'. Notable designs also included the 1970s faux alloy 'Rostyle' (found on MGB models) and the American 'Wolfrace'.

 Armature

An armature is sometimes called a 'buck', but this can get confused with 'seating buck'.

Clay is heavy, expensive and temperature-sensitive, and if applied too thickly, it is prone to cracking under its own weight. For these reasons, clay models of any scale are built up over a supporting armature of wood and foam. In full-size models, they will also have a steel ‘chassis' with axles - road wheels aiding both reality and maneuverability.

The armature's dimensions will be based on those taken from tape and package drawing information, making allowance for a sufficient layer of clay for sculptural maneuver.

 Concept Sketch

Generally, sketches, which may initially take creative liberties (particularly with proportion), will eventually be required to acknowledge the constraints of the package drawing and of reality.

Concept sketches will be free of such inhibiting constraints. They will be used to stimulate creative design ideas and directions and to propose novel solutions. Alternatively, they may be sketches that demonstrate the conceptual ideas behind the design, its influences or form language.

They may also be commissioned for publication, and as such, are likely to have been 'worked up' in Photoshop, and might be considered to be relaxed, high-impact renderings.

See also sketch

Below: Mercedes C111 (L) and McClaren F1 (R)

Doors

Conventional doors have to obey certain rules: hinge points must be in a vertical plane to avoid having to open a door 'uphill' against its own weight, or being dragged 'downhill' by it. 'Double parallel' hinges enabled the huge doors of the Renault Avantime to be opened in 'normal-sized' spaces, but provided the manufacturers, Matra, with an assembly nightmare.

But there are other forms of door, some which allow much more visual freedom and delight.

 

Gull Wing Doors

Hinged along the roof and resemble a bird's wings when opened upwards, these first appeared on the 1952 Mercedes-Benz 300SL racing cars. They were a logical German engineering solution to the problem of providing access yet still preserved the integrity of the tubular spaceframe's necessarily high and wide sills. The resulting visual delight was purely incidental...

Top-hinged doors reappeared on the 1974 Bricklin and the infamous 1981 DeLorean, and with variations: the 1991 Toyota Sera and the 2003 Ferrari Enzo both have one hinge in the roof and the other at the base of the A-pillar, while the Mercedes SLR McLaren has 'swing wing' doors with both hinges on the A-pillar.

Rolls-Royce Phantom Drophead Coupe (above) and Mazda RX-8 below (left) and Honda Element (right)

‘Suicide' (or ‘Barn') Doors

Doors hinged at their rear, or trailing, edge. In the 1920s and 30s, it was quite common for all doors to be hinged from the B-pillars. Occasionally forced open by air pressure created by the forward movement of the car lead to their name, these were subsequently banned.

Suicide doors have been recently re-introduced in the rear of 'extended cab' pick-up trucks, the Mazda RX-8 and the Honda Element. Like the 1937 Lancia Aprilia and 1961 'Kennedy' Lincoln Continental, the RX-8 has no B-pillar (legislation is met by clever and robust engineering). The completely open body sides offer unrivalled access to the rear seats of a coupe.

BMW has coined the more elegant term 'coach doors' for its current Rolls-Royce models.

1971 Lamborghini CountachScissor Doors

These doors pivot expensively upwards on a single hinge, aided by a gas strut. Though they solve the problem of opening a very long door in a confined space, they create another - that of turning a low-slung sports car into a garage roof-scraping one.

Scissor doors first made production on the 1971 Lamborghini Countach, were retained for its replacement, the 1990 Diablo, and have become a Lamborghini trademark.

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

 Light

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 railsMohican 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'Spaceframe

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. 

The Renault Espace is an example of a one-box car, as is the original Twingo. Twingo 2 (right) is closer to a more conventional two-box profile

 One-Box (Monospace or Monovolume)

The principal volumes of the traditional sedan can be split into separate compartments or boxes: the hood/bonnet is the first box; the passenger compartment the second, and the trunk/boot the third - i.e. it's a 'three-box' car. A three or five-door hatchback (no separate trunk compartment) is a 'two-box' car.

A 'one-box' design is achieved by pulling the base of a hatchback's A-pillars and screen forward, but unlike cab-forward designs, the driver and passenger are left where they are. The impression from within is one of spaciousness - though the space gained is largely unusable

One-box designs communicate extra size or volume: the spacious and versatile 1997 Mercedes A-Class is actually shorter than the current, cramped Mini. The main drawbacks are the shift of the A-pillars from the drivers' peripheral vision towards his direct field of vision, and solar gain from the panoramic windscreens.

Though Fiat might challenge the claim, the 1992 Renault Twingo is generally regarded as the first mass-produced one-box car. Commercial vehicles with 'forward control' seating have been one-box for years which is perhaps why Americans refer to their MPVs as 'vans'.

Package Drawing of the Lotus Evora Package Drawing

Although 'artistic license' with perspective, proportion (and wheel diameter) may be expected and understood in both 2-D and 3-D, the reality exists in the package drawing. Drawn over a 'tens lines' grid to a stated scale, it can be measured.

Typically, the package drawing is delivered, via the engineers, to designers as an assembled collection of largely non-negotiable 'hard points' in the form of the unclothed functional contents of a car. This will include recommended length, width and height, wheel centers, engine, drivetrain and fuel tank location, screen angle and position, maximum and minimum percentile manikin positions (with sightlines) which will also impact on the interior's design, as will inner wheelarch intrusion, etc.

In 2-D elevation, or 3-D CAD form, all this will provide the initial underlay over and around, which a designer will have to demonstrate his sketches can be persuaded to fit - without loss of 'character'.

See also package

 Ramp Angles

The Approach Angle is measured by drawing a tangent from the leading edge of a front tire upwards to the lowest point on the front overhang.

The Departure Angle, by a line similarly drawn from the trailing edge of a rear tire to the lower rear overhang.

The Breakover Angle is that created by drawing tangents from the trailing edge of the front tire, and the leading edge of a rear tire to meet at the center point under the sill/rocker panel.

There is no legislation covering ramp angles, but maximizing them is functionally critical on off-road vehicles and of cosmetic interest to owners of sports cars with minimal ground clearance. 

Rendering

A rendering is the definitive expression of a design idea. Although light, shade, color and reflections - all possibly computer-enhanced (typically using Photoshop) - may be expected 'ingredients' of a rendering, it has more to do with the precision, accuracy and care with which a design is described. This is quite likely to be 'sharpened' by the use of drawing aids such as ellipse guides and French curves.

Photo-realistic definition won't be required between designers well used to looking at, enjoying and 'interpreting' sketches, but is necessary to explain and sell a design idea to, for example, non-designer clients in decision-making roles (such as senior management). In some cases, common views and colors may even be stipulated to remove preference between competing renderings.

Sketches are usually done in Biro or soft Prismacolor pencil

Sketch

(See also concept sketch, rendering, package drawing, tape drawing, underlay)

Drawing is still regarded as the language of designers. Sketches are an important visual expression of a designer's creative thought process, but not generally the end product.

Sketches are used as an aid to evolving and visualizing an idea. Initially they will be rapid, exploratory and ‘evocative' rather than definitive - trying to catch the 'spirit' or 'mood' of the idea. The line quality, detail and form definition will become clearer as an idea is developed (hence sometimes, development sketch) until it is resolved in a rendering. A sketch is, by definition, unfinished, though most designers prefer the relaxed 'atmospheric looseness' and 'un self-consciousness' of sketches.

There is debate about whether sketching is a thinking process in itself, whether the thinking and sketching are 'simultaneous', or whether the thinking is done 'normally' and transmitted, via the hand, to paper, for appraisal by the eye.

Sketches are not generally made for other people and development sketches or 'thinking drawings', complete with center, section and perspective construction lines, may never actually be seen. In this sense, if they have no development potential, sketches can be thought of as 'disposable' rather than ‘precious'. Having said that, these are an important record of both a designer's range of ideas and the ability to develop any preferred idea.

Favorite weapons are a soft, blue Prismacolor or Derwent pencil (which easily produce expressive lines) or, for the more skilled, a Biro (which doesn't) on thin 'layout' paper. Sketching may also be done on the computer using Photoshop, but most designers find the lack of 'immediacy' inhibits the process. The expression 'napkin sketch' defines the notion of 'immediacy'.

Sketch Model

In the creative sequence, the sketch model is used as a 'quick and dirty' (and cheap) means of translating a 2-D sketch into 3-D to make sure that the essence of the graphically successful sketch is not lost - or indeed, to confirm that the translation is actually possible. As with the sketch, the sketch model is a means to an end, not an end in itself.

For students, this will mean a small-scale - 1/10 will do it - blue Styrofoam model; for the professionals it's more likely to be a ¼ scale clay model. For both, there is the 3-D computer-modeling (usually using Alias software) alternative, the simple objective being to map-in the broad surfaces and, importantly, check the conjunctions of these surfaces. As these 3-D renderings are developed they may be checked in 'real' 3-D by milling a rough foam or small rapid-prototyped 'wax' model before committing considerable resources to milling-out a full-size model either in clay or high-density foam.

Designers use a spline to develop Renault Megane model 

Spline

Another term with shipyard origins. A spline is a long strip of flexible wood, sprung steel or plastic which is used as a guide to draw or model smooth curves.

Held against its natural spring either at the ends or at a number of fixed points with weights, it will take the line which minimizes the energy required to bend it, and adopt the smoothest possible 'natural' curve in its attempt to straighten itself out.

A spline may have a constant or tapered section. A constant-sectioned spline held only at the ends will produce a constant curve; a tapered spline, held similarily, will produce a curve which will accelerate, or speed up towards the thinner end: it will be, effectively, a French curve.

In the days before computers, long splines were also used by car body engineers at full stretch on full-size drafting tables. But, in the 1940s, mathematicians studying the spline shape derived a formula known as the spline curve or function, which led to its use in computer-aided surface design.

Holden Efijy concept (above). Iconic Mini (below right) did not follow trends of fashion, while Chrysler PT Cruiser quickly became 'last season'.

 Styling

1) The term 'styling' tends to be used in a dismissive, derogatory sense to imply superficiality. This however, denies the notion that it may, in itself, have some value, not merely be skin-deep, second rate design.

Style is closely linked to fashion with its ever-changing seasons, but somehow the stylistic changes that conspire to produce 'this season's look' in the fashion world, while often polarizing opinion, seem to escape criticism. Some cars with a high style content often turn out to have a short 'honeymoon' period: Chrysler's PT Cruiser and Crossfire initially had would-be purchasers queuing, but quickly became very 'last season'.

A 'sense of style' can be created (and thereby conferred on the owner) and there are certainly cars which cut across social, gender and age boundaries and achieve timeless stylishness by not following trends or the dictates of fashion.

At its superficial best, styling may dominate function, but shouldn't compromise it. It is an exercise in form and semantics - the emotional trigger that attracts us in the first place, and like anything else it can be done supremely well or truly badly.

2) 'Styling' as an abbreviation of 'Styling Studio'. For example, Jaguar hung on to the term longer than most automotive studios, but changed it on the appointment of Ian Callum as Director of Design. However, it was always useful in differentiating a Design Studio from those other areas where design activities happened - chassis design, engine design, etc.

Tape drawing examples

 Tape Drawing

Full-sized or scale line 'drawings' of side and end elevations of a design made on translucent plastic film stretched on a vertical surface over a 10cm grid (known as 'tens lines') and package information, using rolls of black masking tape, photographic tape or purpose-manufactured Japanese drawing tapes.

These crêpe tapes are stretchable for creating curves - but have enough 'body' for these curves to flow naturally - and are lightly sticky, to enable regular repositioning for line-adjustment purposes - the equivalent of 'rubbing out'.

Their purpose is to provide accurate, measurable, linear information relative to the 'tens lines' grid to the team of sculptors or modelers working on the clay model. In this sense, they are purely functional and are not pictures. However, the addition of airbrushed color, light and shade, and the full range of tape widths creates the 'tape rendering' which, in full-size form, can quickly and cheaply provide an accurate impression of the 'presence' of a design proposal - albeit in elevation. A whole extra dimension is achieved in the bigger studios using full-size, fully rotatable, 3-D digital images projected on to 'power walls'.

The same tapes are used in 3-D too, for much the same purpose, providing a line for modelers to work to, or adding definition to clay models of any scale.

Underlays aid the gradual and accurate development of sketches

Underlay

The slight transparency of vellum and the thin white paper in layout - or marker - pads allows the use of underlays to aid the sketch and sketch development process.

Elevational package drawings, photos with useful perspective placed underneath, will show through and can be sketched over as can previous drawings, making adjustment or improvement straightforward. Some view this as 'cheating', but it's really a way of speeding-up the creative process and is standard industry practice.

If spirit-based felt-tipped marker pens are used, layout pads of 'bleed-proof' marker paper will prevent the ink seeping through and spoiling the underlay (but this will slightly 'deaden' the colors).