Since packaging is carried out parallel to the final design of the outer body shell, a close co-operation of the vehicle engineers with designers and aerodynamics engineers is necessary. Therefore package plans which contain substantial bordering contours necessary for free space and construction space in the longitudinal and the transverse section are prepared for the entire vehicle (figure above and next two slides). Furthermore they represent the body as well as the vehicle specific reference points, the eye ellipses, the various visibility beams, the bordering contours for the head movements of the passengers, as well as their positioning as a result of an ergonomically optimised interior layout. Therefore the package plans contain all the necessary specifications for the layout and design of the interior. The freedom of design for the designers at this point however, should be limited to areas where substantial regulations, ergonomic requirements or functional restrictions demand attention.