上面介绍了屋架角度画线尺的构造,现在谈谈它的使用方法。使用屋架角度画线尺,首先要在下弦上找出:上弦杆、斜杆一、斜杆二和斜杆三的轴线与下弦轴线的交点。在下弦轴线与上弦轴线交点上画上弦轴线时,要将屋架角度画线尺的尺柄中线对到下弦与斜杆一栏,和你所作 The structure of the truss angle ruler is described above. Now let’s talk about how to use it. To use the truss angle to draw the ruler, first find the intersection of the axis of the upper chord, the slant-rod one, the slant-rod two and the slant-bar three and the lower chord axis on the lower chord. When you draw the string axis at the intersection of the lower string axis and the upper string axis, you should align the ruler centerline of the truss angle drawing ruler to the lower string and the diagonal string, and you