This paper presents a generic functional design modelling methodology applied in the computer-aided design (CAD) environment to associate functional considerations and physical models of the design. Function concept modelling represents the engineering design purposes of the product elements and is usually considered to be interdependent from the detailed geometric solutions. Although CAD is prevailing in modelling geometry of the design artefacts, functional considerations, or design intents, are often not represented systematically and explicitly. The gaps between functional and geometrical representations of the design models require an extensive research to unveil their associations and interactions. Functional feature, and the corresponding semantic representation with the built-in mechanisms, is proposed in this paper to support a CAD methodology that models the interrelations between functional and physical considerations of the design and drives the design through functional perspective. Abstract geometry features are used as functional concept carriers with certain geometries to link functional design considerations in the detailed design model. A case study of a designed product that is used in the oil extraction process from oil sands in Canada is presented to demonstrate the feasibility of the proposed methodology.