The presented research describes the holistic development of a modular lightweight timber shell. So-called segmented timber shells approximate curved geometries with the use of planar plates, thus combining the excellent structural performance of double curved shells with the resource-efficient prefabrication of timber modules using only planar elements. Segmented timber shells constitute a novel building system that demands for innovative approaches on structural design and construction technologies. The geometric complexity of plate shells in conjunction with the particularities of the building material wood pose great challenges to the computational design and planning processes as structural requirements and fabrication constraints determine the shell design at early design phases. This paper discusses the design development and construction of the BUGA Wood Pavilion: A segmented timber shell structure made of hollow cassette components. Particular emphasis lies on the technical challenges of the employed building system, notably structural design and analysis, detailing solutions and the construction process. The authors further describe the integrative structural design and optimization methods developed for the timber shell in question. The BUGA Wood Pavilion demonstrates the possibilities of lightweight and sustainable wood architecture merging the merits of integrative design, structural engineering and high-tech robotic fabrication methods.