The regulations on emissions from a combustion engine vehicle are getting tougher with increasing awareness on sustainability, requiring the exhaust after-treatment systems to constantly evolve to the changes in the legislation. To establish a leading position in the competitive market, companies must adapt to these changes within a reasonable timeframe. With Scania’s extensive focus on Simulation-driven design, the product development process at Scania is highly iterative. A considerable amount of time is spent on generating a specific model for a simulation from the existing Computer-aided Design (CAD) model and pre-processing it. Thus, the purpose of this thesis is to investigate how design and simulation teams can collectively work to automatically generate a discretized model from the existing CAD model, thereby reducing repetitive work. As an outcome of this project, a method is developed comprising of two automation modules. The first module, proposed to be used by a design engineer, automatically generates a simulation-specific model from the existing CAD model. The second module, proposed to be used by a simulation engineer, automatically discretizes the model. Based on two case study assemblies, it is shown that the proposed method is significantly robust and has the potential to reduce product development time remarkably.