Intersection of Curved Solids (平面与立体相交)

When a plane intersects surfaces of a solid, a definite edge is formed. The definite edge is called the intersection of the plane and the solid. The plane is called an intersecting plane. The planar areasurrounded by the intersection (loops of lines or curves) is called a section (see Fig.3-11). Common seen engineering cut-solids are shown in Figure 3-12. 

平面与立体表面相交时的交线,称为截交线,这个平面称为截平面,由截交线围成的平面图形称为断面,

如图3-11所示。工程上常见的截切体如图3-12所示。