“Multiple rulers parallelism”—a study on architectural ruler based on traditional architecture of the Zuojiang Valley in the Guangxi Province

As core elements of traditional construction, architectural rulers governed historical building practices. Using three-dimensional scans of nine buildings in the Zuojiang river basin, this study reconstructed ruler systems using the integer ruler system. Results demonstrated that gable wall thickness was the key scaling factor for structural width proportions. The architecture exhibited a parallel phenomenon of multiple rulers at individual sites. This study advances the understanding of vernacular architectural while providing quantitative data for heritage restoration.