Vertical urbanisation is perceived as necessary to accommodate a growing population but is associated with severe risks for human well-being. It requires a profound understanding of how architectural designs can ensure visually readable and liveable environments before it has been built. However, current digital representation techniques fail to address the diverse interests of non-experts. Emerging biometric technologies may deliver the missing user information to involve (future) inhabitants at different stages of the planning process. The study aims to gain insight into how non-experts (visually) experience 3D city visualizations of designed urban areas. In two laboratory studies, university students were randomly assigned to view a set of the same level of detail images from one of two planned urban area developments in the Netherlands. Using eye-tracking technology, the visual behaviour metrics of fixation count and duration and general eye-movement patterns were recorded for each image, followed by a short survey. The results show how visual behaviour and perception are remarkably similar across different detail levels, implying that 3D visualizations of planned urban developments can be examined by non-experts much earlier in the design process than previously thought.