The continuously increasing product complexity on the one side, and the demand to constantly decrease development times and costs on the other, require new development processes in the automotive industry. This paper describes a product development process which, by intensively and systematically applying computer-aided modeling techniques, makes a significant contribution to the management of this tremendous complexity in a cost- and time- efficient manner. The presented process strives for a widespread usage of modeling techniques (such as physical system modeling and simulation, model-based control system design, rapid prototyping, etc.) over all technical domains involved in the product (mechanics, hydraulics, electrics, electronics, software, etc.) as well as over several stages of the product development process. Key to this concept though is not just the intensive use of these techniques throughout the whole development process, but the holistic approach: Rather than having standalone systems for different tasks/domains, it is strongly strived for one commonly used tool chain/compatible tools which is/are applied to the whole process. This allows for the sharing of one commonly used holistic model, which elaborates throughout the development process. The holistic model becomes “the one real source” of the development process, the overall technical specification of the product, which is also applied to define the interfaces between domains, departments and even to the supplier. Furthermore, the holistic model promotes a high level of reuse: Model portions may be reused/shared between departments, domains, customer and supplier, and even different development projects. How the holistic model-based development process is applied to several different tasks from different development domains using tools such as computer simulation, rapid prototyping or test-bench-based hardware in the loop simulation, is shown by means of an example of the development of an electrified powertrain of a recreational vehicle as carried out by BRP-Powertrain.