[4.1 图形](4.1%E5%9B%BE%E5%BD%A2.md) [4.2 平面](4.2%E5%B9%B3%E9%9D%A2.md) [4.3 实体](4.3%E5%AE%9E%E4%BD%93.md) [4.4 造型](4.4%E9%80%A0%E5%9E%8B.md) [4.5 布尔运算](4.5%E5%B8%83%E5%B0%94%E8%BF%90%E7%AE%97.md)