Church of San Lorenzo in Turin was designed and built by Guarino Guarini in the second half of 17th century and became distinguished for its special dome system and its geometrical configuration. Guarini is well-known for applying complex geometries and conic sections in his domed churches. But for the first time he developed his new pattern of dome with interlacing bands with fully independent structural ribs in church of San Lorenzo. The main target of this study is to present the relation between the geometry and structure in this church. In this research, first, Guarini’s artistic perspective and scientific knowledge are considered to find their influences on the design of the church. Second, the church is described to reach a better understanding of its spaces and its geometrical features.

There are different ideas about the procedure of creating the plan of the church and most of them are matters of discussion. The idea examined in this study is based on using the quadrature and starting from the inner side of the central space.