Abstract
This study takes advantage of digital surveying to investigate in reverse the complexity and creativity of architectural composition in religious Baroque buildings while studying a so-called minor architecture, the church of Santa Maria dell'Odigitria in Acireale (CT), whose interior is modeled with geometric rigor, through a design process that is based on the use of simple geometric figures but articulated differently, such as to structure a complex structural and proportional order. The three-dimensional space of a computer instead becomes the core of the unveiling process, the place where the scholar has the opportunity to interact and communicate with millions of points gained, to reason on the geometric and spatial qualities of the object; where the geometric intuition about the genesis of the shape can be verified in real time through a simple query / overlap, in which one can move from measurement to representation, from the spatiality of the real to its discretization and viceversa.
TopReverse Modeling Approach For The Geometric Interpretation Of Historical Architectures
Reverse modeling or reverse engineering is a metholodogical approach that, in the field of industrial design, describes the transition between a huge amount of geometric data about an object represented by its 3D coordinates – point cloud – and its mathematical description obtained from the numeric model by extrapolating exemplary sections used as directrices and generatrices.
Most of the software for such an “inverse” modelling, starting from point clouds, is provided with a series of two-dimensional (plans and circles) and three-dimensional (cylinders, spheres, cones) graphical primitives able to fit a surface to a specific selection of points by means of best-fit algorithms that extract the best interpolating geometries. These algorithms take into account the typical noise of each laser scanner, thus mediating the thickness of the cloud of points in a single geometry.
In the architectural heritage field, current systems for 3D metric data acquisition (3D laser scanners) realize a sampling of three-dimensional points with a step, chosen by the scholar according to his research needs. This is done during the acquisition phase and it represents the density of the survey, that is the representation detail. This point cloud is a numerical model that can be considered an objective fact (Docci, Gaiani & Migliari, 2001).
Key Terms in this Chapter
NURBS: Are a mathematical representation commonly used in computer graphics for generating and representing curves, surfaces, free form surfaces and solids. In this case numerical codes are structured and arranged to describe geometric shapes, dimensions to associate with these forms or qualitative information that is useful to their representation.
Incannucciate Vaults: Covering structures that do not fulfill a supporting function and are formed by one skeleton of wooden ribs, encased peripherally in the walls. The centerings were nailed with mats of reeds, the whole was finished at the intrados with mortar and plaster.
Realine Vaults: Covering structures with a supporting function, they are constituted by a conglomerate that in the area of Catania is made of pumice and gypsum. The carpentry was constituted by centerings and planking timber on which a layer of mortar was spread.