Using three-dimensional modeling for reconstructing a polished stone tool

The methods of 3D modeling have been increasingly used in archaeology, making it possible to comprehensively analyze individual artifacts at a new level of accuracy and create a basis for statistical comparison between large groups of objects. This article describes application of 3D modeling methods to reconstructing a polished stone tool. During processing of the Neolithic evidence from the Ruchei Smolokurnyi site (Northern Angara Region), it was noticed that after breakage, polished tools (adzes, axes, or pestles) were always remodeled into other items, such as scrapers, planers, chisel-like tools, bifaces, and even cores. One of large chisel-like tools has preserved numerous spots of polished surface after remodeling. In the process of working with a high-precision 3D copy of this stone artifact, a number of cross-sections intersecting the remains of the polished surface were made. All known large polished items from that site were longitudinally symmetrical. The method of mirror symmetry was applied, which increased the area of the polished surface on the reconstructed object. By analyzing the original and mirrored sections, it was possible to determine the main features of the original tool. It had asymmetry in profile relative to the longitudinal axis. One side was more convex with a weakly distinguished longitudinal rib in the center. The other side was flatter, less convex, with more thorough polishing extending to the longitudinal edges. After analyzing the images and comparing them with a series of cross-sections of morphologically similar intact items, the original polished tool was identified as adze. Thus, the methods of 3D modeling have made it possible to reconstruct the type and supposed appearance of the original polished tool.