Unspoken in many of the skills of an expert designer is the ability to manipulate geometric concepts. The packaging of an aircraft's undercarriage mechanism into a compartment in the wing, the recognition of a stress-raising feature likely to lead to component failure, and the development of a plan of the machining operations to manufacture a product all require a very sophisticated geometric reasoning ability. The lack of accepted definitions and the imprecise use of terminology have created significant confusion about the differences between Parametric Design and Variational Design. The authors believe that there are fundamental differences between the two design methodologies which affect their suitability and value in different design situations. The authors concur that a Variational Design system should encourage an engineer to explore more design alternatives because it makes changing the design approach much easier. In addition, the mathematical foundation of variational geometry allows a variational design system to provide information about tolerancing, mechanisms and optimisation which is not conceivable with Parametric Design systems. We reason that variational design is intrinsically a more powerful design technique that is more appropriate to the preliminary design process.