Geometric Characterization of Late-Baroque Domes in Sicily

This study focuses on historical rotational domes, whose surface is obtained by the rotation of a profile around a vertical axis. The recognition of the geometrical rules underlying the dome design is fundamental to correctly interpret its initial conception, the project and construction phases and all the changes over time. To this aim, the paper proposes two different procedures of Best Fit Analysis (BFA) applied on the inner surfaces of domes, which are obtained geometrically and analytically, respectively. Starting from a 3D survey, the objective is to determine the best approximating geometric shape of a dome and the existing point-to-point deviations between the geometric and the surveyed shape. In particular, the proposed analytical BFA uses all the 3D surveyed points as input data to obtain the geometric model. The BFA procedures were applied to seven examples of Sicilian domes built between the eighteenth and nineteenth centuries.