Abstract
Motives: Urban form plays a crucial role in achieving sustainability, shaping accessibility, multifunctionality, and resilience within cities. However, the challenge remains in quantifying sustainable urban form in a way that captures both its spatial characteristics and its apacity to foster multifunctionality.Aim: This study explores the sustainability of urban form in Lithuania through a nature-inspired approach, integrating biomimicry principles with quantitative modeling and simulative mathematical graph-based analysis. The research draws from established urban theories, including New Urbanism, the compact city, the 15-minute city, identifying multifunctionality and bottom-up self-organization as fundamental characteristics of both natural and urban systems. Literature analysis highlights the growing interest in urban form and sustainability, revealing strong thematic linkages between land use, transportation, and public health. Empirical analysis is conducted at multiple scales, from the national level to individual city comparisons, employing graph-based spatial modeling to assess walkability, accessibility, and functional distribution. The methodology integrates GIS-based tools, simulative urban network modeling, and weighted centrality measures to identify urban structures that inherently support sustainability principles. Results demonstrate that Lithuanian cities exhibit distinct patterns of multifunctionality, influenced by their historical evolution, urban morphology, and planning paradigms. Findings reinforce the hierarchical and emergent nature of sustainable urban form, validating the concept of pervasive centrality in urban networks. Moreover, the study highlights the importance of spatial configuration over function quantity in fostering walkable, accessible, and resilient urban areas. While the proposed model successfully identifies clusters of 15-minute city neighborhoods, it also reveals limitations, including the role of large-scale infrastructure interventions and administrative boundaries in shaping urban accessibility.Results: This research contributes to the ongoing discourse on sustainable urbanism by providing a quantitative, spatially explicit framework for evaluating urban form sustainability. It highlights the need for integrated planning approaches that balance bottom-up urban evolution with strategic policy interventions to create cities that are both sustainable and functionally diverse.