众所周知，解决二面角问题，寻找或求作二面角的平面角是关键．平面角如何作，作在什么位置上，往往是困难所在．传统的做法较多地从线的角度理解平面角，有时难免一叶障目，不见森林．本文拟从面面关系的角度认识平面角，把二面角的平面角看成面面相交的结果，试图由此产... As we all know, solving the dihedral angle problem, finding or calculating the planar angle of a dihedral angle is the key. How to make the plane angle and where to do it is often difficult. The traditional approach is to understand the plane angle from the perspective of the line. Sometimes it is difficult to avoid the blind sight and not see the forest. This article intends to understand the plane angle from the perspective of the facial relationship, and consider the plane angle of the dihedral angle as the result of the intersection of the planes, trying to produce this...