Transparency combines inside and outside of the space. In order to enable maximum transparency, minumum use of material is needed. The more glass surfaces are used, the more maximum transparent surfaces are created. Complex systems, since they can be developed and formed by both truss and cable systems and likewise by shells such as grid shell and lattice shell, they all are reviewed and analyzed. The example of these systems are divided into different categories and for each category graph samples are produced. Complexity is determined by hierarchy, geometry, integration and new details. When more than one structural system in one building is recognized, then possibly that building is a complex one. Because it certainly involves integration of the structures, hierarchical production (built) process and new details. Complex structures sometimes stand as an entity but sometimes they are in cooperation with some other structures. These buildings are the ones in which the structural material used at a minimum degree whereas the transparency is at the maximum degree. Formally improbable structures become possible by the details used in constructing these complex structures.