在管道施工中经常遇到在平面上有水平折角α,同时在纵断上也有垂直折角β。如图(一)中ABCD为管道走向,从平面图中看为ABC′D′,从沿管体轴线的纵剖面图中看为ABCD。其中垂直夹角CBC′为β,水平夹角ABC′为α,而管线实际夹角ABC即空间角为θ。 In the pipeline construction often encountered in the plane with a horizontal angle α, while in the longitudinal section also has a vertical angle β. As shown in Figure (A) ABCD for the pipeline to go from the plan view as ABC’D ’, along the longitudinal axis of the tube body view as ABCD. Where the vertical angle CBC ’is β, the horizontal angle ABC’ is α, and the actual angle ABC of the pipeline, that is, the space angle θ.