Traditional GIS (Geographic Information System)-based visibility analysis has been conducted mainly two-dimensionally based on the concept isovist in architectural and urban space or the concept viewshed in terrain and landscape analysis. Recent developments of non-GIS spherical analysis such as SOI, SVF, and Sky Opening, have inspired development of a GIS-based volumetric visibility analysis referred as the VIEWSPHERE. It was proposed in this dissertation for measuring the quality of urban open space, by volumetric computation of ambient optic array, a concept originated from Gibson’s ecological perception theory. Through its development, we can operate volumetric computation of visible urban space. With the consideration of the third dimension of urban space, we argue that a volumetric visibility impact assessment for large-scale urban design and development will provide a more relevant result than planar measurement and will provide better information about how urban quality can be achieved by the alternative urban forms and interventions.