Within the context of modern industries, additive manufacturing (AM) plays a critical role. Design for AM (DfAM) requires defining design actions related to the product's geometry under development. DfAM affects design choices such as the type of process, the material, the geometry, and the model's features. Knowledge-based engineering (KBE) is promising for integrating DfAM principles in the early phases of product development. Still, few limitations are noticed, such as the real interoperability between DfAM and 3D CAD systems, leading to the application of proper DfAM rules downstream of the 3D modeling. This paper aims to describe a method to formalize AM engineering knowledge used as a repository to develop a CAD-integrated decision su...