The REGION command is used to convert closed objects such as polylines, polygons, circles, ellipses, closed splines, and donuts into two dimensional regions.

After we create a region, we can then modify it using various three dimensional tools.

How to access the REGION command:

1. From Menu: Home > Draw > Region, as shown in the following picture,

2. By entering command: REGION, as shown in the following picture,

How to convert circle to region with REGION command?