Abstract
In recent years, in addition to the consolidated interest of the scientific community towards 3D digital surveying methods for the documentation of cultural heritage, the need to virtually use it is rising, to promote and enhance its value. This chapter focuses on the use of new technologies aimed at the documentation and communication of Knowledge, with the objective of involving the community through a participatory and immersive approach. Technologies, visualization, and fruition are, therefore, the key terms of the work in progress conducted by a team from the University of Catania and aimed at the documentation, safeguard, and communication of the ecclesiastical architectural heritage of Acireale, built after the earthquake of 1693.
TopIntroduction
In recent years, the processes of 3D data acquisition based on images (Structure from Motion - SfM - methodology) and range data (digital survey through Laser Scanner) have widely been used, not only for the graphic documentation and the creation of a digital database of the artifacts surveyed, but also for the detailed and accurate 3D modeling and reconstruction of architectural and archeological assets, of single monuments or entire cities. In particular, the models obtained through SfM methodology and laser scanner technologies, when adequately processed, are optimal for immersive Virtual Reality (VR) applications. Depending on the purpose of the virtual experience to be created and the type of access to the digital model (on site, through a VR installation, or via the web), immersion can also be guaranteed using a sequence of spherical images. Virtual Reality allows a wide category of users to emotionally experience real places that are often inaccessible or difficult to visit because of a complex management and several conservation issues; it is the case, from some points of view, of the two places analyzed within this research, that is aimed at using the digital data from digital survey to simulate innovative virtual visiting routes inside the Baroque religious architecture of Acireale. This can be considered as the first step to create a complete tourist-religious itinerary for the knowledge of the historical-typological, stylistic-formal and decorative features of the entire eighteenth-century ecclesiastical heritage (Magnano di San Lio, 2000). The two case studies represent elegant examples of Baroque architecture: the planimetric layout (founded on the oval shape) of the church of Santa Venera and the splendor of the frescoed vaults of the church of Santa Maria del Suffragio are constants of the historical period in which they were built. Specifically, Santa Venera is a complex centrally-planned building whose construction began in 1758, based on a design by Paolo Amico Guarrera. This church has already been the subject of a previous study by this research group, aimed at analyzing the geometric-spatial component and at deeply understanding the geometrical rules subtended to the planimetric layout and to the vaulted surface (Galizia & D'Agostino, 2017). Santa Maria del Suffragio, instead, is one of the most representative examples of the artistic activity of the local painter Pietro Paolo Vasta: the explosion of colors of the purgatory-themed fresco cycle, made in 1751, enriches the simple planimetric layout with its single hall (Magnano di San Lio, 1992; Blanco, 1968). The virtual models obtained are the result of in-depth investigations (archive documents, iconographic researches, geometric and architectural studies) which constitute the cognitive data for a digitization as faithful as possible to the real artifacts.
The ultimate aim of this study is to create virtual environments which can revive the spirit of the eighteenth-century artists through the figurative seduction and the emotional involvement of the users. The general methodology adopted in both case studies is based on the integrated use of digital survey (Laser Scanner and Structure from Motion Photogrammetry), 3D modeling and VR technologies for a detailed documentation and an accurate reconstruction of the architectures and of the atmosphere that characterizes the interior of the two churches. As will be seen, it was therefore decided to follow two different paths (but with the same purpose) in order to create two types of virtual simulation starting from the data acquired through the digital survey campaigns.
Specifically, the virtual tour inside the church of Santa Venera was created by using spherical images (obtained with an Iris 360 camera). This approach guaranteed an easy and immediate immersive experience, considering that raster contents require few computational resources and are easy to use on digital platforms (like mobile devices).
Key Terms in this Chapter
Equirectangular Image: It is an unrolling of the spherical image onto the plane, the width is exactly twice its height.
Playful Learning: It is a term used in education and psychology to describe how it is possible to learn using playful components.
Baroque: Term used to indicate an artistic movement born in Italy (more precisely in Rome) between the seventeenth century and the first half of the eighteenth century and that has had original developments throughout Europe. This cultural current has been expressed in literature, philosophy, figurative art, music, and especially in architecture. It followed Renaissance art and Mannerism and preceded the Rococo (in the past often referred to as “late Baroque”) and Neoclassical styles. In architecture, the Baroque style is characterized by aspects aimed at creating a strong sense of wonder, such as complex volumes, exuberant details, movement, magnificence, contrast between light and shadow or full and empty.
Edutainment: This term is a neologism formed by the fusion of the words “education” and “entertainment”. It is a media designed to educate through the use of a playful component.
Reverse Modeling: It is the process by which it is possible to obtain the morphology of an object from the digital acquisition of the physical model.
Retopology: It is the process of converting high-resolution models into simpler and lighter meshes. The basic idea is to create another mesh that simplifies the original HD asset.
Unwrapping: This term indicates the first step in the UV mapping process, that corresponds with the flattening of the mesh on a 2D plane. Once the mesh has been unwrapped, an UV map is created. The UV map is the flat representation of the surface of a 3D model, used to easily wrap textures. The U and V refer to the horizontal and vertical axes of the 2D space, as X, Y and Z are already being used for the 3D space.
Polygonal Mesh: It is a collection of vertices, edges and faces that defines the shape of an object in space.
NURBS geometry: NURBS stands for “Non Uniform Rational Basis-Splines”, a class of geometric curves used in computer graphics to represent curves and surfaces. A NURBS is the mathematical representation that software uses to define geometric objects. A NURBS is defined by four characteristics: the degree, the control points, the knots and the evaluation rule.
Serious Game: It is a digital game that does not have exclusively or primarily a purpose of entertainment but contains educational elements. Ideally, in this kind of educational tool the serious and playful aspects are in balance.