The styling features most likely to raise the pulse and lower the resistance of a car buyer -- shapely fenders, a rakish roofline and curves the neighbors will envy -- are easy for designers to sketch, but all too often, impossible for factories to produce.
Car and truck bodies are shaped by many factors, including the practical need to carry loads (a box is ideal) and the fuel-economy benefit of an aerodynamic form (which favors a rounded profile).
But another limit to a vehicle's shapeliness is the ability to manufacture its exterior panels with the contours and creases envisioned by designers. Metal will bend only so far before it tears or cracks; alternatives like fiberglass are more forgiving, but carry the stigma of being "plastic."
New technologies for bending sheets of steel and aluminum, and for lowering the cost of lightweight materials like carbon-fiber composites, are making it possible for automakers to produce vehicles more faithful to the lines originally drawn by the styling studio.
Full article here