Professional paper
https://doi.org/10.17018/portal.2020.11
Application of 3D Digitization of Cultural Heritage: Architectural Elements of the Cistercian Abbey in Topusko
Valerija Gligora
orcid.org/0000-0001-5101-8575
Andrej Janeš
orcid.org/0000-0003-0683-3364
; Croatian Conservation Institute, Department for Archaeology, Zagreb, Croatia
Abstract
During the 1999 excavations near the remains of the façade of the Cistercian Abbey church, located in the Opatovina park in Topusko, a large quantity of stone architectural elements was found. During 2018, documentation of the architectural elements was performed using 3D modelling. The use of computers in archaeology has changed with the development of the technology, and in the 1990s, 3D models were used more often for archaeology, although their beginnings can be traced back to the mid-1980s. Today, archaeology can distinguish two concepts related to 3D modelling: 3D digitization and 3D reconstruction. 3D digitization is a process by which the spatial shape of an object is determined and recorded in digital form, and 3D reconstruction describes the reconstruction of an object or parts of an object that no longer exist, with the help of 3D modelling. 3D models of architectural elements in Topusko were made using image-based modelling, one of the techniques of 3D digitization. Each of the 36 elements was photographed with a series of overlapping photographs, and the photographs were processed using Agisoft Photoscan. The program uses the photos to generate a sparse point cloud using the structure-from-motion (SfM) process. The program recognizes points that appear in multiple photos and connects them, and it discards points that do not match, while using the connected points to calculate the position and orientation of the camera when shooting. The next step is to create a dense point cloud. Using a multiview stereo (MVS) workflow, the program uses points that have fewer repetitions than the points used to create the sparse point cloud. Once the point cloud is created, it is possible to create a mesh, the step in which the program creates the geometry of the object. The last step is to create the texture of the 3D model. After creating a 3D model, it is possible to export an orthomosaic, which is later imported into AutoCAD and serves as a basis for creating design documentation. Orthomosaic maps of the floor plan, side view and cross-section were made for the architectural elements in Topusko, so that they could be drawn in AutoCAD. In addition to creating documentation, such 3D models can be used for virtual restoration or virtual anastylosis.
Keywords
Topusko; Cistercian Abbey; 3D model; 3D digitization; image-based modelling; stone architectural elements; archaeological documentation
Hrčak ID:
250644
URI
Publication date:
20.12.2020.
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