An Integrated Digital Framework for Multi-Objective Analysis and Design Decisions in Historic Area Renewal: A Case Study of Hehuatang, Nanjing

Urban renewal in China increasingly focuses on extensive residential historic areas embedded within cities. Recent practice emphasizes refined and progressive renewal strategies, which require multi-dimensional evaluations of micro-scale spatial elements and the formulation of differentiated renewal pathways. The progressive renewal also requires repeated evaluation and adjustment. However, conventional evaluation and decision-making largely rely on manual judgment, which can be subjective and inefficient when dealing with complex information. To address these limitations, this study proposes a digital methodological workflow integrating multi-objective analysis with design decision-making. The workflow targets spatial design issues at three hierarchical levels—streets, plots, and buildings—and is implemented through a multi-module platform. The platform consists of an analytical evaluation module and a design decision module. The analytical module provides quantitative assessments across morphological and non-morphological dimensions, while the design decision module combines analytical results with expected parameters to generate optimization suggestions for spatial structures and identify renewal pathways for spatial elements. Tested in the conservation and renewal planning of Hehuatang in Nanjing, the platform demonstrates the ability to efficiently compare spatial structure schemes and rapidly determine renewal pathways, improving the scientific rigor and efficiency of renewal planning.