Decision-Making Framework for Building Assemblies Using nD BIM: Integration of Time, Cost, and Environmental Criteria

The increasing demand for efficient and sustainable building design has led to the development of nD BIM, which integrates multiple dimensions such as time (4D), cost (5D), and environmental performance (6D and beyond). However, existing approaches often lack an integrated decision-making framework that supports the simultaneous evaluation of these criteria, particularly in the early design phase of building envelope systems. This study proposes a unified nD BIM-based decision-making framework for building assemblies, using authoring tools, namely the BIM approach and LCA methodology. The proposed framework is applied in an empirical case study, where several design variants of a multi-residential building are developed and analyzed through 4D and 5D BIM models to assess construction time and costs, while environmental impacts are evaluated using selected key indicators, e.g., Global Warming Potential (GWP), Acidification Potential (AP), and the consumption of non-renewable primary energy (PENRT). The outcomes of these analyses are integrated into a multi-criteria decision-making model based on a weighting system. The results demonstrate that an nD BIM-based unified weighted decision model enhances decision-making by enabling transparent comparison of design alternatives and identification of trade-offs, thereby supporting more efficient and sustainable building envelope design while improving decision quality and reducing uncertainty for designers, engineers, and project investors.