Offset

Creates one or more offset copies of a single object. The object can be open or closed. For closed objects, the offsets will also be closed.
The offsets are created so that linear segments remain parallel. When possible, arc start and end angles remain the same as well.

1. Activate the function, and select the object (line, arc, polyline, polygon, etc.) you want to offset.
   
   
2. Set the offset distance either by entering it into the first field of  the Inspector Bar.
                          
                                         
   
3. Next, enter the number of Sets in the Inspector Bar. This is the total number of copies, including the original.
4. Select the side of the object where you want to place the copies.
   
   The offset copies are made on the selected side.
   
   
5. If you enter a Z Offset, each offset curve will be separated from the adjacent one by this distance.
   
   
6. You can use the same parameters to offset other objects, you can change the parameters, or select Cancel from the local menu or Inspector Bar to exit the tool.

Local menu option: 
Rounded Corners: The exterior corners (relative to the offset direction) will be rounded.