Urban Porosity. A morphological Key Category for the optimization of the CAS’s environmental and energy performance.

This paper illustrates Porosity seen in IMM as fundamental morphological characteristic of urban systems, integration of two basic components of urban space: Volumes and Voids. It aims to highlight the role of Porosity in the relationship between urban morphology and environmental-energy performances with objective considerations and evaluations of its characteristics based on values and indicators. Hence IMM as systemic methodology presents some key findings in this process to describe it objectively. This paper aims to presents an innovative way to estimate Porosity as a Key Category and anticipates its role in finding a correct balance between level of Compactness, Complexity, and Connectivity in the urban system (CAS). Actually in IMM balancing these determinants (resulting from the interaction of the Key categories) is considered the foundation of a best performing CAS (sustainable urban form) and any of them would not be sufficient on its own to achieve the result.