“The relation of head to body determines the standard by which we assess all other proportions in nature,” writes Kenneth Clark in The Nude. He notes in this must-read for all aesthetes published in 1956 that the human eye is disturbed by bodily imperfections and therefore doesn’t judge the nude as a living organism, but as a design.

Slimming in fashion is directly related to sleekness in the car

A few years back, speaking with Chris Bangle, then BMW’s director of design, he told me to “replace nude with car, and you will understand everything about cars”. One of the controversial designer’s last projects at the carmaker was Gina.

The concept car took this notion of car as human to a different level with an outer skin made of cloth – the virtually seamless polyethylene-coated Lycra stretch fabric shielding a moveable substructure beneath.

You could say the car’s skeleton is draped in metal in much the same way our bodies are in cloth. Cars can have taut muscles or be lean like a runner; be as slim as a catwalk model, or just plain sexy.

We criticise a car for looking bloated and sneer at the ones with a big behind. The car is shamelessly anthropomorphic. But, how closely do the frivolous world of fashion – where trends come and go literally by the season – and the more sedate world of the motorcar interact?

Things are changing, albeit slowly. With cars coming to the market at a much quicker pace, and with such extensive personalisation programmes on offer, we areseeing a stronger dialogue between the two worlds.

In both worlds, the most important aspect is the initial architecture, as there is a limit to what you can camouflage if the proportions are wrong. Nargess Gharani, co-founder of London-based fashion label GharaniStrok and an independent design consultant, agrees that the initial concept needs to work before you even consider developing it further.

“If an original design is beautiful and therefore flattering but the trim used is badly positioned, or of poor quality, it will destroy the original design,” she explains.

For Audi, this means following a clear genetic code, which involves having a very high shoulder line and a very condensed green house. At Mercedes-Benz, the shoulder line is the most erotic feature on the car; it shows power and is therefore crucial to the overall appearance.

Slimming in fashion is directly related to sleekness in the car. Vertical lines create a longer, leaner figure in the same way horizontal ones form visual length on the car.

Gharani comments that on a garment it is more effective to work with seaming, which is a more subtle way of creating the same visual impact. Too many character lines running the length of the body can become visually distracting.

The BMW way is to sculpt its lines. For the carmaker, lines have to be authentic; they are intersections of surfaces and only applied when two surfaces happen to intersect – much like seaming in tailoring. Other tricks of the trade include elongating the DLO (day light opening), blending the hood for a slimmer visage, or using light and shade on the surface to create a feelingof slenderness.

Accessorising the car can also work wonders to highlight aspects and hide flaws. Wheels, headlamps, the grille and other graphic elements on the car can work in a similar way to buttons, jewellery, shoes and handbags. “Heals make you look slimmer and give better posture,” says Gharani.

But what current car excites the fashionista? The Nissan Cube, it seems, with its 60s-inspired cabin, clean lines and use of colour as well as the clever manipulation of material that pushes boundaries yet maintains functionality.

Gharani explains: “This, I believe, is very important in both fashion and car design, as you have to be fresh and push boundaries, but never keep your eyes off what is commercially viable.”