# Three-Dimensional Reconstruction of the Early Christian Temples of the Roman Fortress of Pitiunt
## 2 Materials and Methods  
In recent decades, the development of new technologies and software has led to the widespread use of photogrammetry, 3D reconstruction and engineering modelling in archaeological research and work on the protection of historical and cultural heritage sites [13; 14; 15; 16; 17; 18]. In this regard, the reconstruction and visualization of the original appearance of the Roman fortress of Pitiunt, an important economic, military and Christian centre of the eastern Black Sea region during Late Antiquity and the Early Middle Ages, is of great interest. This work, aimed at creating a virtual exhibition for the \"Great Pitiunt\" Museum in Pitsunda, has been carried out by the Markula Archaeological Expedition since 2018. The complex and varied task was divided into several stages. In the first stage, from 2018 to 2019, a 3D reconstruction of the fortress of Pitiunt in its heyday (the second half of the 4 th century to the beginning of the 5 th century) was carried out [19]. The work resulted in models of defensive structures and infrastructure elements for the fortification. Initially, a probable appearance of Temple Nos. 1 and 3 was proposed as model-filling elements without significant details. In the second stage, there was a detailed elaboration of the appearance of the floor mosaics which decorated Temple No. 2 and which are partially preserved on the floor of Temple No. 3. A detailed description of the process and justification of each element of the composition is given in this work [20]. After the reconstruction of the historical environment and the interior elements, it was possible to proceed directly to the 3D reconstruction of the original appearance of the site of ecclesiasticl architecture of the 4 th-6 th centuries. A major advantage of the temple complex of the Roman fortress of Pitiunt is that the site has been the subject of very detailed research. This lasting expedition produced a wealth of documentation, including detailed drawings and descriptions of the site, photographs and analytical papers. All this is complemented by a large archaeological collection of artefacts held at the local Great Pitiunt Museum Reserve. The good state of conservation of the site makes it possible to study in situ the materials used, the quality of the masonry, the thickness of the lime mortar and the presence of opus mixtum brick bands separating the layers of marine conglomerate masonry. The richness of the tile remains allows one to determine the geometric dimensions and their application in the model. This constitutes the fundamental quantitative material on which the work presented is based. During the research, a comprehensive methodology for the 3D reconstruction of historical sites was developed. The methodology includes the following stages:  
1. Clarification of the ground plan, preserved fragments of the structure, building materials, details, etc. This work is based on the use of photogrammetry involving taking pictures of the objects using a digital camera from the ground and/or using a UAV. The photogrammetric 3D model was used to create the primary plans, projections and sections of the reconstructed temple. 2. Study of the excavated materials, building materials to clarify missing dimensions and features of the building, and variations in the construction of some elements. Studying literature to find architectural analogues of the modelled temple and to determine the influence of various architectural schools on the proportions and assumed vertical dimensions. 4. Producing drawings, projections and sections, as well as design variants for unpreserved elements based on architectural analogues. 5. A 3D model of the temple must be constructed according to the received drawings, with verification and correction of the power scheme of the building, taking into account the variations of proportions. Detailed modelling of door and light openings, as well as decorative elements, must also be done, taking into account analogues and building traditions accepted at that time. 6.