Talibon

Performing Photogrammetry on a Traditional Philippines Sword

by Drew Rausch

3D Photogrammetry is the process by which many photographs are stitched together in order to create a 3D model. The staff of the University of Michigan Museum of Anthropological Archaeology is in process of learning this useful technique. This sword was chosen for a small test project on the unique difficulties that may arise when performing photogrammetry on cultural artifacts.The thin and long shape, the reflective nature of metal, and the uneven weight of the object all create unique challenges for digitization. In creating this model, a great deal of experience and information on the process of digitizing a difficult object was learned. 

The angle of the hilt on this sword tells us that this is a Visayan fighting sword known as the Talibon. The Talibon has a large curved blade that tapers from its flat thick false-edge to a razor sharp and curved true-edge, the blade is designed similar in thickness to an ax. While the Talibon sword can be effective at clearing brush and slaughtering game, it is a design that was specifically made for combat.  The people of the Visayan Islands and Southern Luzon were the main users of this style. In addition to its more practical and brutal applications, the sword can be strikingly beautiful in both carving and shape. 

The Philippines has a long tradition of iron sword making, dating back over a thousand years before Spanish colonization. The Talibon is a specific variation within the Filipino war bolo family of weaponry. War bolos are single edged knives and swords historically wielded one handed by Philippine warriors. Their main tactical advantage is their multi-use nature. Unlike the highly specialized fighting swords of Europe, China, and Japan, most variants of the war bolo have use in hunting, agriculture, and combat. The Talibon design is known from the 18th-19th centuries, but it is thought to be descended from the ancient sword-making traditions of the Philippines, as evidenced by the traditional curve of the blade and traditional designs that often score the pommel and scabbard.

The specimen pictured here has rattan binding on the hilt, and a dark patina wood finish on the scabbard with elaborate carving on the pommel. It was acquired during a University of Michigan Museum of Anthropological Archaeology expedition to the Philippines in 1925. It was collected under the assumption that the sword was used during the Philippine-American war of 1899. The blade is just over one and a half feet long, or nearly 50 centimeters, and shows some wear. Notice the diamond motif on the three petal flower pommel, this pattern is a traditional carving style that symbolizes a reticulated python, an animal that is both ecologically and culturally important to the Philippines. 

According to documentation associated with the collection of the Talibon, the pommel is made of the horn of a Carabao, a large variant of the Asian Water Buffalo that has been used for farm labor and food production for thousands of years. It is believed to have been introduced by Malayan people migrating to the Philippine Islands over two thousand years ago. This pommel was likely created out of a male Carabao’s horn. In the photo below, you can see a comparison of the pommel and blade to the horn of a female Carabao. A male’s horns would be significantly larger in size.

One of the main challenges with performing photogrammetry on this artifact is its long and thin shape. The thin shape makes it difficult to acquire the amount of photo overlap needed for the stitching software to complete the model. Another challenge is the reflectivity of the blade. Notice that the surface of the Talibon’s blade appears a dull gray on the models, whereas the actual object is fairly reflective and shiny. 

For the first attempt, both sides of the blade were photographed on a turntable covered with black felt. Over 200 photographs were taken with several close ups of the hilt in order to get the appropriate level of detail. Agisoft Metashape software was used to create two halves of the Talibon, but it was unable to create one finished combined model of both sides. This attempt was completed by mounting each half on the same plane.

Blender, a 3D software graphics toolset was then used to merge the two halves together manually. Even with some clean-up, the seam between the two halves was still very rough.

 second attempt was then made by photographing both sides of the talibon on a turntable, with a white background. This time, the images were processed with Epic Games’ RealityCapture software. This software was able to stitch the two halves together. The software did have trouble creating a smooth edge for the sharp edge of the blade, which was cleaned up manually, for this final display.

Photogrammetry can be a great tool for preserving cultural heritage. For the past decade advances in software technology have allowed for great strides in museum work regarding digitization of 3D models. While imperfect, models created with photogrammetry can be used for public outreach and educational purposes when the physical objects are unavailable. As can be seen with the models created of the Talibon, it can require a great deal of effort to create models of more complicated cultural objects. For contrast, the University of Michigan Museum of Paleontology has successfully streamlined the process of digitizing paleontological specimens with a permanent photogrammetry setup for their University of Michigan Online Repository of Fossils. In their case, objects are often uniform and more dull, rock or fossil structures. Sharp edges, symmetrical patterns, and refined materials make anthropological photogrammetry more difficult, but incredibly rewarding when completed. We plan to continue and expand the use of photogrammetry to educate and share our collection with our community.