古建大木作营造时,每遇圆形构件(如檩、柱等)则是用不规则的原木,砍刨成规格的圆柱体,然后进行制作、安装。在砍刨圆柱体时,要顺着原木身外皮弹顺线。按每相邻的两条顺线砍一个平面,砍成基本接近圆形的十六面体,刨去楞角,即成为规格的圆柱体。砍十六面体,总计要弹三十二条顺线。并且要求按顺线砍出的平面,每相对应的两个平面的距离都是符合直径要求,因此在弹顺线时 When the ancient building blocks are built, every time a circular member (such as a pole, a pillar, etc.) is used, irregular wood logs are cut into cylindrical bodies of a specific size, and then manufactured and installed. When you cut the cylinder, you must follow the outline of the skin. Cut a plane by each adjacent two straight lines, chop a hexadecahedron with a nearly circular shape, and plan to remove the corners, that is, to become a cylinder of specifications. Hexahedrons were cut and a total of 32 straight lines were played. And it is required to cut out the plane along the tangent line, and the distance between each corresponding two planes is in accordance with the diameter requirement, so when the line is played,