【摘要】 目前,在所有“画法几何”教材中,对圆锥体和椭圆锥体投影的作法都是近似的。本文提出了一种新的准确作图方法。这种方法,是利用椭圆与圆的对应关系,通过变换将椭圆转换成圆,然后再依照圆来求出圆锥体和椭圆锥体的转向线、表面上的点和线的准确位置。文章对正圆锥、斜圆锥、正椭圆锥、斜椭圆锥,均处在一般位置时的投影、转向线、面上取点等分别提出了准确作图方法。更多还原

【Abstract】 At present, it is approximate to draw projections of cone and elliptic cone in the all descriptive geometry teaching materials. A new accurate drawing method is presented in this paper. It can be used to transfer ellipse to circle by the corresponding relationship of ellipse and circle, and then, the accurate positions of diversion lines, points and lines on the surface of the cone and the elliptic cone can be determined according to the circle. In the end, accurate drawing methods for upright and oblique cone, and upright and oblique elliptic cone are presented.更多还原