Regions are two-dimensional enclosed areas you create from closed shapes called loops. A loop is a closed boundary that is made up of straight and curved objects which do not intersect themselves. Loops can be combinations of lines, lightweight polylines, 2D and 3D polylines, circles, arcs, ellipses, elliptical arcs, splines, 3D faces, traces, and solids.
面域是用户从称为环的闭合形状创建的二维闭合区域。环是由直线和不自交的曲线组成的封闭边界。环可以是直线、轻量优化多段线、2维和3维多段线，圆、圆弧、椭圆、椭圆弧、样条曲线、三维面、宽线和实体的组合。
The objects that make up the loops must either be closed or form closed areas by sharing endpoints with other objects. They must also be coplanar (on the same plane). The loops that make up a region must be defined as an array of objects.
组成环的对象必须是闭合的，或者是通过与其他对象共享端点而形成闭合的区域。所有这些对象还必须共面（在同一个平面上）。组成面域的环必须定义为对象的数组。
For more information about working with regions, see “Create and Combine Areas (Regions)” in the AutoCAD User's Guide.
有关操作面域的详细信息，请参见《AutoCAD 用户手册》中的“创建和合并区域（面域）”。
