When the view cannot show the plane well , the plane symbol using two continuous thin lines as diagonals is used to indicate it , as shown in fig . 17 当回转体上图形不能充分表达平面时,可用平面符号表示该平面,如图17所示。
The view of symmetrical part can be drawn a half or quarter part , and two continuous thin lines paralleling to each other should be drawn on the two ends of the perpendicular center line , as shown in fig . 12 当机件上具有相同的结构要素(如孔、槽)并按一定规律分布时,只需要画出几个完整的结构,其余的可用细实线连接或画出他们的中心位置,并在图中注明其总数,如图12所示。