直线与投影面倾角和的最大最小值求法探讨

Method of Seeking the Maximum and Minimum Inclination Sum of a Straight Line to Projection Surface

讨论直线与三个投影面倾角和的最大值与最小值的求法，及三个角之间的相互关系，求出了三倾角和的最大值与最小值，并简要介绍了“直线的空间角”的概念，及其在实际中的应用。

Method of seeking the maximum and minimum of the inclinations'sum of a straight line to the three projection surface and relations between the three in clination are discussed detailedly in this article. And the conception of 'Space angle of the straight line' and its application in pratice is introduced consisely.