The chapter presents an integrated approach to the design of anatomically customized biomedical products, combining the principles of Knowledge-Based Engineering (KBE) with additive manufacturing technologies. The rapid advancement of digital engineering tools and the growing demand for patient-specific treatment necessitate a shift from traditional, manually driven workflows toward automation grounded in formalized expert knowledge. Key CAD modelling methodologies, both parametric and non-parametric, are discussed, alongside their applications in the design of prostheses, orthoses, implants, and surgical models. The chapter outlines the development of intelligent CAD models, automated design systems, and the progressive transition from conventional to fully automated design environments. Particular attention is given to the structure and classification of engineering knowledge, its capture, representation, and implementation within KBE systems that enable large-scale mass customization of biomedical products. The use of Finite Element Analysis (FEA) for evaluating and optimizing the mechanical performance of additively manufactured orthopedic devices is also presented. Ultimately, the chapter emphasizes that digital transformation and knowledge-based automation reconcile individual patient needs with industrial-scale production, defining a new paradigm of innovation in biomedical engineering.