Abstract: An installation is provided for the precise mutual alignment and welding together of the main components of a vehicle body to form a complete body shell during production of the prototype thereof. The components of the prototype body are joined in precise position in a first tacking station, which can be closed in the manner of a cage, and tacked through the openings in the cage. In a subsequent welding station, the tacked sheet-metal parts of the body, which is now only supported on the underside, but otherwise freely accessible on all sides, are fully welded together. This division of the work makes prototype production efficient and ergonomically very favorable.