Preliminary aircraft design and cabin design are essential and well-established steps within the product development cycle for modern passenger aircraft. In practice, the execution usually takes place sequentially, with the preliminary design defining a basic layout and the detail implementation following in a subsequent step. In order to enable higher fidelity assessment of the cabin early on in the design process, for example by means of virtual reality applications, this paper proposes an interface, which can derive detailed 3D geometry of the fuselage and cabin from preliminary design data provided in the Common Parametric Aircraft Configuration Schema (CPACS) using a knowledge-based engineering approach. Missing information on the cabin and fuselage structure is detected and generated by applying a set of interconnected design rules. Similarly to the TiGL Geometry Library for CPACS, the presented interface furthermore provides a knowledge-based parameter engine, which translates the parametric information from CPACS into CAD-geometry using the Open Cascade Technology library. The engine is explicitly focused on the fuselage including details such as extruded frame and stringer profiles or extruded bulkheads. The parametric and geometric models can be shared to enable a comprehensive integration of cabin analysis in automated collaborative aircraft design chains, not only with respect to passenger comfort, but also manufacturability or crash safety. Virtual reality visualizations using platforms such as Unity are a particularly interesting application. Using triangulated representations of the CAD-geometry, highly immersive virtual mock-ups can be built by merging the data from CPACS with external high-fidelity component models, even at early design stages. Therefore, a new evolution of the cabin definition in CPACS is proposed, which establishes the necessary interfaces. Aside from the high degree of immersion, another advantage of virtual reality environments is their interactivity. This offers promising opportunites to provide engineers with a virtual environment to intuitively interact with and explore complex product data sets like CPACS by visualizing metadata and analysis results along with the geometry.