As a digital methodology for creating the 3D Model of the Funko Pop! figurine of Vincent van Gogh, we utilised both photogrammetry and structure from motion.
Photogrammetry is a method used to capture physical objects by retrieving information through measuring, recording and interpreting photos (Papadopoulos, n.d). The photographs taken, thereby, play an important role. In our case, we needed to do close-range photogrammetry, meaning that the camera was stabilized on a tripod and photos were taken from different angles of the object. Furthermore, to be able to do a 3D reconstruction of the object the photos needed to overlap by 60 percent (Papadopoulos, n.d). As our figure was put on a turning table, we needed to make sure that the object was moving just enough to still overlap the previous picture. Even though many pictures were taken from several angles, this proved to be a struggle since Agisoft Metashape which analysed and re-created the digital 3D model was not able to comprehend every part of the body (e.g. the back of the straw hat). Therefore, we decided to also take pictures of the figurines upside-down to obtain more angles.
Moreover, an important aspect of photogrammetry is that lens distortion should be avoided. We did not realize until the end that the photos we took had minimal lens distortion (some pictures were 40 instead of 41). Although those pictures were not recommended to be used, they still helped in reconstructing the 3D model. This is because they contained important details that Metashape needed for reconstructing the 3D model. However, it is worth noting that because of the use of different focal lengths, when we merged the two chunks on Metashape, one model ended up being bigger than the other. Thus, they could not align properly. To solve this issue, we decided to only keep the model of the straw hat from the first chunk and the rest of Vincent's body from the other ones.
Furthermore, one of the disadvantages of using photogrammetry is the dependency on good light (Papadopoulos, n.d). Because of the structure of the object specifically the head, we had a problem with shadows. For instance, in the back of the straw hat there were many shadows which made it difficult for the software to understand the shape and re-create it. This was perhaps one of the main issues that complicated the process of creating the model in the software. Thus, to help Metashape we began by creating masks for each picture. Although it was quite time-consuming, it definitely made a difference for the final product.
