【摘要】 本文运用图解法，在对圆环面正轴测投影外形线的曲线性质进行投影分析的基础上，导出了圆环面正轴测投影外形线的参数方程；给出了产生尖点的几何条件和判别式；解决了尖点和虚实分界点的定位问题，为圆环面正轴测投影的计算机绘图提供了可靠的教学依据。更多还原

【Abstract】 The authors have derived a parametric equation of the contour curve by the graphic method and through the analysis of its nature on the orthographic axonometric projection of a torus.In this paper a geometrical condition leading to the tip point and a discriminant is giv qn,and tlie orientation of the tip point and dashed and real points of division is suplied.In addition,it is mathematically proved that there exists a practical possibility of drawing the orthographic axonometric projection of a torus with a computer.更多还原