Segmentation of stone walls from 3D models for stone wall BIM creation

Abstract

Traditionally, the mapping of stone walls has relied on two-dimensional drawings and photographs, which present challenges such as the lack of three-dimensional information, dependence on individual skills, and significant labor demands. This study aims to enhance the efficiency of creating "Ishigaki Karte" for systematically recording and managing the current state and structure of cultural heritage stone walls. We propose a method to generate line drawings from high-density 3D mesh models created using Structure- from-Motion Multi-View Stereo (SfM-MVS). By applying the Segment Anything Model (SAM) to the texture images of the 3D models, we automatically segment individual stone wall regions and extract boundary information, which is then exported in DXF format. To verify accuracy, we compared the automatically generated boundaries with manually delineated boundaries in a selected area of Nagoya Castle. The results showed a precision of 0.90 and a recall of 0.79, confirming that the segmentation of each stone wall was achieved with high accuracy.