Nowadays, virtual reality technologies and immersive virtual reality (VR) apps allow people to view, explore, engage with and learn about historic monuments and buildings, historic sites, and even historic scenes. To preserve our cultural heritage for future generations. it is essential that damaged and dilapidated historic artefacts are accurately documented, and that steps are taken to improve user experiences in the areas of virtual visits, science and education. This paper describes an approach to reconstruct and restore historic buildings and mural paintings. The work process uses digital models that are then inserted into an interactive and immersive VR environment. Windows-Mixed Reality is used to visualize the said VR environment. The work method was applied at a United Nations Educational, Scientific and Cultural Organisation (UNESCO) World Heritage Site in Tenerife (Canary Islands, Spain), thereby creating a virtual three dimensional (3D) rendering of the architectural structures of the St Augustine Church in La Laguna and its murals. A combination of topography and terrestrial photogrammetry was used to reconstruct its architectural features, and the digital imaging tool DStretch^® to recover its murals. The resulting 3D model was then inserted into an immersive and interactive VR environment created using the cross-platform game engine Unity. One of the greatest challenges of this project revolved around recovering the dilapidated and virtually nonexistent mural paintings using DStretch^®. However, the final result is an immersive and interactive VR environment containing architectural and artistic information created within the video game engine Unity, which thereby allows the user to explore, observe and interact with a cultural heritage site in real time.

Extended In the archaeology of the Canary Islands (Spain), there are many studies based on the usage of new technologies to contribute to the identification and description of rock art engravings through high-resolution digital models (Martín, 2005; Martín, Velasco, González & Ramírez, 2007; Senén & Cuenca, 2016; Navarro & Cancel, 2019). This paper is supported by these documentation techniques and digital analysis in order to deepen into the characterization of the damaged rock art station Casa del Samarín (House of Samarín), or Tagoro del Rey, in Los Llanos de Ifara, south of the island of Tenerife (Figs. 1). Twenty-one panels conserved in situ were documented (Fig. 6). Geometric-linear, geometric with an oval and rectangular trend and figurative ones can be distinguished. The blocks [1] that compose the engravings station belong to a rocky basalt outcrop, to which other free-standing blocks are attached, forming a circle. The shape that describes this set of blocks is defined as a "cabin" or circular-shaped structure.This set of engravings, made on a basalt rocky outcrop with a planar factory, show a tendency to suffer from exfoliation and are affected by internal stresses. The intrinsic characteristics of this stone support, together with their exposure to anthropic actions and strong insolation, condition its fragility, with the risk of losing part of the representations that it houses. Given the threat posed by its gradual deterioration, we seek to ensure its digital preservation through precision three-dimensional (3D) records, the engravings inventory, the record of their conservation state and the understanding of the degradation processes that are affecting the outcrop. What has been explained will be addressed quarterly, to observe the evolution of any material changes every three months.The registration work consisted of taking four photogrammetric surveys in eight months; the surveys were georeferenced by means of a centimetric Global Navigation Satellite System (GNSS) and a total station. Structure from Motion (SfM) technology enabled the researchers to generate high-precision 3D models in an affordable way, not only in terms of cost but also ease of use. Digital copies with Geographic Information System GIS technology were extracted from them, being exportable in shapefile format (Fig. 7).As regards the documentation of existing pathologies, assuming standardized lexicon and classification criteria (IPCE, 2013), together with a rigorous information systematization, was key for achieving agile handling of the data collected and for facilitating monitoring tasks (Fig. 8). Damage maps were created for collecting the location and scope of the alterations. The complex volumetry of the outcrop and the varied orientation of the panels marked the need to resort to 3D editing so that all their faces could be properly registered (Fig. 10). This project was performed with a 3D design program, Blender®. Thanks to an imaging analysis process, internal textures of 3D models also provided relevant graphic support for the pictographic content and the conservation state (Figs. 11 & 14). DStretch® (Harman, 2008), a plugin implemented in the scientific image processing software ImageJTM, was used for this purpose. To conclude, researchers relied on CloudCompare (Girardeau-Montaut, 2015), an advanced 3D data processing software, to tackle a morphometric analysis that allowed us to detect the appearance of formal changes along with the recorded sequences (Figs. 12 & 15). In this process, the distances between two records, taken after six months, were computed with the Cloud to Mesh (C2M) tool, based on the Chamfer distance algorithm (Ruiz et al., 2016: 120).Registration file cards and damage maps clearly highlighted the main conditions: material losses (shown in orange) and breaks (in green) have affected the outcrop in a generalized way. Furthermore, sedimentary deposits (blue) are concentrated in interstices; while lichen colonies (idem) do so in the least sun-exposed areas. The use of DStretch® highlighted modern excoriations of anthropogenic origin and contributed to distinguishing recent material losses from the older ones, already affected by an incipient patina. Finally, thanks to morphological analysis, a new detachment (Fig. 15b) and a generalized displacement of exempt elements (Figs. 12 & 15) were detected. These displacements indicate outstanding manipulation, which could lead to decontextualizations or new fragmentations.Regarding the archaeological interpretation, macroscopic observation of exempt blocks located in the vicinity of the station and the zenith representation of the immediate environment from photogrammetry, have shown that they are forming a set of attached structures (Fig. 13). The site redefinition and the diagnosis of its very weakened defensive system show the need to intensify the archaeological study of this area, so emblematic for the archaeology of the south of Tenerife, in addition to establishing preventive conservation measures that can contribute to its stabilization. [1] Geological unit of size greater than 300 mm, term standardized by the USCS (Unified Soil Classification System).

This paper proposes the use of the DStretch image analysis tool applied to the study and formal analysis of eighteenth-century mural paintings in the San Agustín Church of San Cristóbal de La Laguna, a World Heritage city in Spain. Thanks to the technification of digital documentation, it has been possible to recover virtually this pictorial group that currently is almost completely lost due to a fire occurred in 1964. A work methodology that aims to achieve a reliable and rigorous recreation is proposed, supported by free software DStretch. This tool, which is conceived for research on rock art, is based on decorrelation processes, used in digital image treatment, which improve the readability of an image. The method offers an interesting applicability to the study of the historical mural painting analyzed and enhance the objectivity of its virtual reintegration.

Gracias a la revolución tecnológica que vive el campo de la documentación del patrimonio vemos cómo los registros 3D se consolidan como recurso documental y se extienden con infinidad de propósitos, entre ellos los estudios morfométricos. Con la intención de contribuir en este campo, proponemos un método encaminado a la detección y cuantificación de cambios formales en bienes de naturaleza metálica, un tipo de material susceptible de sufrir daños físicos en un corto período de tiempo. La puesta en práctica de dicha metodología se ejemplifica a través del estudio efectuado sobre un casco de hierro del s. XVI, conservado en un avanzado estado de mineralización. Fue registrado antes y después de un préstamo temporal apoyándonos en dos sistemas de gran difusión en el campo de la digitalización 3D: el escaneado por luz estructurada y la fotogrametría. Finalmente, se compararon sus registros mediante la herramienta de análisis de datos 3D CloudCompare para detectar sus posibles diferencias.

This paper presents multi-disciplinary research undertaken between 2022 and 2024 at El Riscal, the only rock art station known in Seville (Andalusia, Spain), a territory otherwise very rich in Late Prehistoric archaeological remains. Discovered in the 1980s and first published in the early 1990s, El Riscal presents engraved motifs not documented in other parts of southern Spain, where schematic-style painted rock art is prevalent. The set of methods employed in this research includes petrology, chemical characterisation (XRD, SEM-EDS), digital photogrammetry and digital image analysis, archaeological prospection and archaeoastronomy. The results throw new light on the characteristics and temporality of the site, with a pervasive significance through time. This, in turn, invites a new approach to the geographical distribution of the various traditions and styles present in Iberian rock art. This research also suggests that re-examining previously published rock art sites could lead to a better understanding of styles, chronologies and traditions.