As previously mentioned, it's all teamwork. If in fact, it's not one of the more seldom new developments, it's all about showing consideration at an early stage, for the needs of the developers responsible for other areas. Whereby, one can certainly sometimes say that it's a case of “first come, first served”.
Indeed, woe is to those whose contradicting developments have reached an advanced stage. Shortly before the start of a VW-Polo series, Ferdinand Piësch once decided to equip the car with more side-strengthening. Now, however important the NCAP-test results may be, the delayed introduction of a series probably also costs millions.
Of course, any form of dissent does not, as a rule, carry solutions to a problem, even in the very early stages. What is needed are regulations to which one can orientate oneself, and which are valid over and above the respective development. It is nevertheless, quite astonishing, how a number of variations are created inside the often restricting bounds of the guidelines, of which some of the more daring conceptions, have recently also asserted themselves. The life of a designer is characterized through a strange dualism, the lonely search for ideas, and the convincing and defending of these ideas inside the team. Together, both components only lead to a self-realization. Indeed, the people who have to guide the designer-teams through the quagmire of over-demands and hopelessness, are to be admired.
The development should be tightly interwoven with the production. Of course the business representatives and the sales/marketing people also play an important part. Oddly enough, the designing is not placed on the same level, but has to interact with all these departments. If it works, design is everything, if it doesn't, it very quickly means nothing at all.
Who has not already experienced the feeling of triumph when his/her design has been realised, or the desolation of it having been rejected? In designing, this begins with the three-dimensional model, the outside of the vehicle is done on a scale of 1 : 5, the interior in fact, is presented at a scale of 1 : 1. One important factor influencing all this has not yet been mentioned, this is the legislation, or to be more precise, the legislation in various countries around the world. In fact, at the moment, it's not the USA who is leading as far as the regulations governing collisions with pedestrians, but Europe.
Amazingly, at the moment (2014), more is being done in the field of interior design. This has a lot to do with the amount of displays. In some cases, unrealizable demands are being made on the operation. Straight away, there are again two neighbouring design-fields, the ergonomics and the haptics. In addition, the dashboards of the most reasonably priced model and the top-of-the-range model can't be too similar but also not too different to operate.
So, enough about the preparation, what we have are models. In the past they were made of wood (see picture below) and of course, they were also used for the manufacturing. One could adapt the sheet-metal, so that afterwards, they would produce bodywork with acceptable seam-gaps. Of course, some of the finishing also had to be done by hand, e.g., if a door was to be replaced.
Nowadays, the shape comes out of a computer. Complimented by a little additional data, the 1 : 5 scale model can be mechanically produced. If the model is approved, a much more expensive full-size model is then created. In this case, the work is more than likely dome by hand. The model can even be spray-painted over a thin film and placed on on a suitable trolley so that it can be pushed outside. Natural sunlight and the design must fit perfectly together. 07/14