Table of Contents
### Working with Regions

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Regions are special AutoCAD objects. In many ways, regions act like 2D planar objects; in other ways, regions exhibit many of the properties of 3D objects. Like 3D surfaces, for example, regions can hide objects “behind” them and can have materials applied to them for rendering purposes. Like 2D objects, regions have no third dimension, or Z-axis information. In many ways, regions can be considered infinitely thin solids.

Technically, regions are enclosed 2D areas. You create regions from closed shapes. Closed shapes consist of a curve or a sequence of curves that define an area on a single plane with a non-self-intersecting boundary. Closed curves can be combinations of lines, polylines, circles, ellipses, elliptical arcs, splines, 3D faces, or solids. The objects that compose a closed curve must either be closed themselves or form a closed area by sharing endpoints with other objects.