The relations between patterns of visibility quantification and perceived values in various urban typologies. An experiment in virtual reality

Urban typologies can be described through their perceptual values, the attractiveness of their spaces, spaciousness and routes provided, dependent on their morphology, geometry, proportions, density and various spatial elements such as landmarks location, buildings facades, green spaces including trees, textures and more. Movement along different urban typologies may result in diverse patterns of visual perception. The Dynamic 3D Visibility Analysis (DVA) model simulates the way pedestrians would potentially observe and experience the urban environment. DVA enables considering various characteristics and types of the built environment, the different surfaces, buildings, landmarks, green areas and the sky view. The DVA model was assessed with experiments in a visualization lab, where participants were immersed in virtual reality environments. Participants were asked to record their perception of density for each path. The model was found to be a reliable indicator for the perceived density along urban paths. The objective of the current work is to explore the relations between patterns of visibility quantification, based on DVA, and perceived values in various urban typologies through an experiment in virtual reality. The case studies are diverse urban fabrics that represent unique typologies; Each assigned to one of three categories: Naturally developed vernacular fabric such as the old city of Venice; pre-planned urban fabrics such as the Barcelona “Eixample” and the Manhattan grid, and singular architectural mega projects such as the “Interlace” project in Singapore. The initial segments of urban fabrics to be analysed were based on the size of an area of four Barcelona blocks in the ‘Eixample’ grid. Most of the urban environments chosen for this study are major touristic attractions commonly known as ‘positive’ environments. Most of them are well known to most participants either from a previous visit or from pictures. DVA along a simulated pedestrian path for each of the above urban typologies was recognized with a unique pattern of visibility. A video of the exact analysed rout along the virtual model was screened to the participants in the visualization lab. All routs are 1 km in length and wander about the urban space in a typical path to each morphology. Movement velocity in the videos is equal. Special consideration was given to representations of the virtual facades and typical elements along the designated routs additionally to the morphology. Participants were asked to evaluate their experience in each urban environment by grading various attributes presented to them. Results show that the visual experience for each virtual path is very different according to the participants. Illuminating relations between patterns of visibility and participants evaluations were found, highlighting a future potential to predict human experience for variant urban fabrics. DVA model could help explain various urban phenomena and can be used to predict and evaluate the human experience in existing urban environments as well as a tool to evaluate future planning and design proposals for better pedestrian experience in future urban environments.