Developing the preliminary cost estimate for the free-form building facade in conjunction with the panel optimization process

Abstract

The exterior surfaces of the free form buildings contain the panels with very complex curvature. While the panels incarnate a symbolic and remarkable building facade in the urban environment, constructing the panels is extremely complex. Because the bigger the curvatures of the panels, the more expensive the construction cost, a free-form building designer needs to perform the process to mitigate the curvatures of the panels at the early design stage without damaging the features of the free-form façade in parallel with estimating the cost to construct the panels (i.e., panel optimization). However, at the upfront design phase, estimating cost of design alternatives and finding a good one that meets both design intention and budget limit is very difficult. Most designers lack understanding, technology, and data on panel optimization. This study suggests how to optimize the panels for free-form facade by using Grasshopper, a widely-used application that a building designer can easily approach as well as how to calculate the construction cost change in conjunction with the optimization process. The panel optimization is mainly carried out by connecting Grasshopper's continuity analysis function with curvature analysis function. A case study is performed on a recently completed free-form building project in Korea to verify the applicability of the study result.