Multi-LOD generative approach for multi-objective sustainability optimization from the early stages of building design

Given the urgency of reducing the buildings' environmental impact, this article focuses on optimizing sustainability from the earliest design phases, when decisions have the greatest influence. To address the challenges posed by the coarse granularity of digital models during the sketching phase and the often-conflicting nature of sustainability criteria, a generative workflow is proposed. This workflow, based on a multi-Level of Detail (LOD) framework, enables the evaluation and tracking of multiple sustainability criteria throughout the design iterations. This systemic methodology integrates automated functional spatial-planning, hierarchical segmentation of construction solutions, and systematic exploration of Pareto-optimal alternatives for bi-objective optimization. The framework is validated during the sketch phase using life-cycle cost and global warming potential, across eight real-world office-building case studies. Feedback from ten construction experts confirms the Proof-of-Concept's effectiveness in supporting both retrospective and prospective decision-making, underscoring its potential to advance sustainable design practices in the Architecture, Engineering, and Construction sector.