Offset/Mirror
Offset (O) or mirror (M) a sketch curve.
Mirror
Create symmetric copies of selected sketch curves across a selected centerline. By default, there is a parent-child relationship between source curves and their symmetric copies.
- 
                On the ribbon Sketch ribbon, select the
                        Mirror tool.

Tip: To find and open a tool, press Ctrl+F. For more information, see Find and Search for Tools. - Select the sketch entities to mirror.
 - On the guide bar, select Axis.
 - 
                Select an axis or line as the centerline to mirror across.
                
                Tip: You can select the red and green sketch axes as centerlines.
 - Select Apply on the guide bar or microdialog.
 - Right-click and mouse through the check mark to exit, or double-right-click.
 
Offset
Create a copy of a sketch curve at a specified distance from the source curve.
- 
                On the Sketch ribbon, select the
                        Offset tool.

Tip: To find and open a tool, press Ctrl+F. For more information, see Find and Search for Tools. - 
                On the guide bar, choose a selection method:
                
- Chain Selection (default): When selecting a sketch entity, automatically select all connected sketch entities as well.
 - Single Selection: Select sketch entities to offset one by one.
 
 - Click-and-drag a sketch entity to offset it.
 - 
                Enter a value for the offset distance and select additional options in the
                    microdialog:
                
To Do this Reverse the direction of the offset Select Reverse Direction 
.Define the gap filling method Select one of the following options from the drop-down menu: - Tangent Extensions: Extend the offset curves on either one or both ends tangentially.
 - Natural Extensions: Extend the offset curves as they naturally occur.
 - Arc Caps: Fill the gap in the offset curve with an arc.
 - Line Caps: Fill the gap in the offset curve with a line.
 
Create a symmetric offset Select Offset Symmetry on the microdialog. Then, select one of the following options from the drop-down menu: - Open: Leave the offset curve open.
 - Line Caps: Create a closed loop with straight ends.
 - Arc Caps: Create a closed loop with rounded ends.
 
This option only applies to open sketch curves.
 - Click Apply on the guide bar or microdialog.
 - Right-click and mouse through the check mark to exit, or double-right-click.