球体透视阴影画法的研究

目的为确定球体在有灭光线下的透视阴线，和画球体透视阴影的作图方法，使曲面体的透视阴影画法得到进一步完善．方法采用辅助投影、透视变换等方法，使球体及球体表面的阴线的新投影具有特殊性，然后在新投影与所求的透视投影或透视阴影之间建立起符合射影几何场的一一对应条件，确定新投影图与所求投影图之间的一一对应关系．利用射影几何场的一一对应关系，可确定球体的透视与透视阴影．结果将求空间非圆苗线的交点问题，转化成求平面上圆与直线、直线与直线的交点问题，使求曲面体透视阴影的作图变得简捷、准确．结论用这种作图方法，简化了复杂问题的图解难度，为相关专业的设计师提供了一种实用的绘图方法．

A New Method for Drawing Shade and Shadow in Spheric Perspective

This paper presents the method of drawing shade and shadow of sphere based on the principle of projective geometry.A new view requires finding by means of an oblique projection.The view of the sphere is shown by a series of the type circular shapes.The elements that tangent along light rays around the sphere are an edge view.The new views and shade and shadow of sphere are a one-to-one correspondence.The Graphic solution is given to locate the pinot of intersection of the line and circular or that of line and line.It is to guide view drawing.