Concept design of cars has traditionally revolved mainly around illustrators creating 2D sketches, the 3D shape only becoming obvious after many drawing iterations and having been painstakingly created by a CAD designer. My approach is very different in that I create the concept itself directly in 3D using subD techniques more commonly being used for animated organic characters. This method is FAST and can be used to evaluate the concept CONTINUALLY in three dimensions, enabling visual tuning of body curves on an all together more intricate level than 2D sketching would ever allow.
The concepts that evolve are good 3D representations of how the car will look, but the subD technique is far from precise and mathematically correct, as a Class-A CAD model would be: I just supply an alternative to the 2D sketch. So what I create is: a non-exact visual concept in three dimensions, visualized in the Sketchfab 3D renderer for 3D interactive viewing by the customer. Different takes on the same design can evolve during the design process, and private models can from time to time be shared online with the customer to steer the design process in the preferred direction.
Go here for a 3D interactive car concept design portfolio.