【摘要】 正交两圆柱的相贯线 ,一般是四次曲线。该曲线在平行其公共对称平面的投影面上的投影 (下称正面投影 )一般是双曲线 ,且多用找点法求出。有时 ,为了简化作图 ,往往采用以大圆柱半径为半径的圆弧代替双曲线近似画出。作者发现 ,该近似作法作出的图形 (圆弧 )与正确的双曲线相比较 ,有时其差异是很大的———尽至到严重失真的程度。为了能客观地把握近似作法合适的选用场合 ,本文在对正确投影与近似画法间误差分析的基础上 ,探讨其比较适合的应用条件更多还原

【Abstract】 The intersection of two right circular cylinders is usually quartic curve. Generally, the projection of the curve which projects on the plane parallel to its common symmetry plane is hyperbola, and it’s plotted by finding nodes. In order to simplify the procedure, we use the arc which radius is the radius of the larger circular cylinder to replace the hyperbola. But sometimes there’s big difference between these two methods. In order to use the approximate drawing method properly, the paper analysis the error between the methods of accurate and approximate drawing, and concluded the conditions that are suitable for the approximate drawing.更多还原