Much research has been conducted into the visualisation of objective space and decision space landscapes. This work moves away from this and investigates a 3D interactive method for linking EA decisions through time with the design of engineering systems. The proposed system shows through an intuitive interface, the design space being explored by the algorithm including decision variable choices, locations that are fixed early on in the optimisation and those problem areas that are difficult for the algorithm to solve. The paper presents a case study in water distribution network design, although the methods described are, in principle, generalisable to other design domains.