‘Good proportions’. It’s a popular refrain from car designers in response to the question: ‘what makes a good design?’. But what are ‘good proportions’? How close is this to the idea of a person having a ‘good figure’ and the ideal human form being one that approximates to the classic superhero?
The proportions of a car are the ratio between its key volumes and shapes. Typically a car designer will be speaking about the proportions that lie within the silhouette of the car, the key ones being: the ratio of hood length to cabin length; the relationship between front overhang, wheelbase and rear over hang; the depth of the day-light-opening (DLO) / side window to the body side. But there are no absolutes even within these key proportions: a curved windshield makes the length of the hood vary according to the angle it is viewed at; a high rocker and prominent light catcher in the body side reduces the visual depth of the body-side; and a lot of plan shape in the corner foreshortens the overhangs from most viewpoints. And there is in-fact a myriad of different proportions that sit within a typical car design that might include the relative size and position of lights, wheel arches, shoulders etc.
What makes ‘good proportions’ then? Well, focusing on those evident just within the side-view of a car, compare those of these two designs: the 2006 Dodge Nitro shown here in red and the 2004 facelift of the Fiat Multipla shown here in silver. Two very different car designs from different cultures, for different markets – although both sold concurrently in Europe for several years and offered similar internal capacity. I've chose n them as they bookend the three core ‘inside the silhouette’ side proportions.
The Dodge has far greater length of hood length to the cabin length compared to the Fiat – its proportions clearly denote far greater emphasis on the engine area whilst the Fiat denotes far greater emphasis on passenger space.
The Dodge has minimal front-overhang that means its rear-overhang gives it a classic rear-wheel-drive ‘sling-shot’ stance, whilst the Fiat’s minimal rear-overhang and longer front-overhang have the classic front-wheel-drive ‘diving forwards’ stance.
Yet, despite these stark proportional differences between the two designs, it is the difference in the proportion of their side windows that has the most marked impact on the identities of these designs: the Dodge has very shallow day-light-opening (DLO) / side window and yet a deep body-side, whilst the Fiat has an exceptionally deep DLO and quite shallow body side. Subconsciously this proportional difference is read (in part) anthropomorphically: the Fiat DLO is the large head of a toddler on its small frame, the Dodge has the pin-head of a superhero on its muscular frame. And this is the kernel of the issue many designers have taken with the Multipla design (lauded though it is by many, including this author): that it has an ungainly, top-heavy set of proportions that its deep side windows mostly create.
So does this answer the question what makes ‘good proportions’? That the anthropological read of a car, subconscious or otherwise, means that we desire proportions that emulate those of a desirable human or superhuman? Forsquare stance with pin-head atop a muscular body? For many this may be true. But then just as not all people aspire to the superhero body shape, or read cars anthropologically – and as car design has so many other ingredients – so there are no hard rules for 'good proportions'.