直接作二次椭圆曲面平截线实形的新方法

研究了二次椭圆曲面与平面相交，求交线实形的方法．该方法的关键在于根据给定的条件利用作辅助曲面来定出交巳知曲面于椭圆截面族的方向，然后将平行于此方向的平面所截得的椭圆向新投影面投形成团，以定出交线实形上的点．

THE NEW METHOD IN DIRECTLY DOING THE SOLID FORM OF SMOOTH CUTTING LINE OF THE SECOND ORDER ELLIPTIC QUADRIC SURFACES

The author has mainly studied the cross of the second order elliptic quadric sur faces with plane and studied the method of solving the solid form of the lines of intersection.A new method was got through studying. The key to the method lies in difining the direction of elliptic section family that crosses with the given quadric surfaces by means of doing auxlilary quadric surface according to the known condition. Then project the ellipse beingcut by the plane that parallels to the direction into a circle on the new projectile plane,so thatthe dots in the solid form of the lines of intersection can be designed.