The program used for the creation of the 3D model was Agisoft Metashape, which is a software that enables generating highly detailed, texturized models. To create models, the software makes use of Structure from Motion (SfM) – a technique that combines photogrammetry (a technique of using 2D photography to recreate shapes and geometries in 3D and determine the relationship between the position of objects in space (Linder, 2003, p. 1) and computer vision, which allows for creating 3D models from 2D sets of images.
While capturing the object (in this case – a model train), we followed rules of SfM capturing. To allow a undisrupted processing by the software, the toy was put on a turntable inside a light box (as shown in picture 1). We surrounded the object with scale bars to support the accurate measurements and position of the 3D model. We took the photos from three different angles (top, middle, bottom) and turned the turntable before each photo. Ideally, adjacent photos should overlap 60%. However, the movement between pictures was too small and resulted in a heavy dataset, which led to the program running at a slow speed. Therefore, in the end, only every fourth photo was used, enabling reaching the desired overlap percentage and smooth processing. The imported dataset was a large set of photographs of the object, which was later aligned. Following this step, a point cloud was created and then cleaned of extraneous data. After the point cloud did not contain any parts of the background, we built the model. The result was satisfactory – the train constituted the only part of the model. However, after building texture, generating masks from selected photos was necessary (see picture 2).
Although this step is usually optional, in this case, applying it has helped tremendously with achieving the desired result. The final step was repeating the process at high quality and exporting the 3D model (Picture 3).
Overall, working with Agisoft Metashape did not pose significant issues. The 3D model, although it possesses minor flaws, is a good representation of reality.