在截交线和相贯线求解中,往往已知的是“面”的两面投影,其特征为“一框、一线”,要求作的是另一投影(框),则根据其“类似性”特点,不但可以方便“求解”,而且更便于作题后图形准确性的判断。现举例说明如下: Often, the two-sided projection of the “face”, which is characterized by “one frame, one line” and which is required to be made by another projection (frame), is often known in the solution of the intersecting lines and the intersecting lines, “Feature, not only convenient” solution ", but also easier to determine the accuracy of the problem after the title. An example is as follows: