Access:
Click the
icon, or select Solid
/ Remove / Extrude from the main
menu. The function will appear on the popup
menu if a closed curve
or a closed sketch is selected.
Remove material by extruding a closed sketch / composite curve on both sides, by the same value and direction.
Important: When using this function, material will be removed only from the current active object. (If only one object exists in the document it is automatically active unless manually deactivated.) See Activate / Deactivate and Activating Objects.
Required Step 1 
Select a closed 2D composite curve or sketch.
Notes:
If you enter Extrude immediately after creating a closed 2D composite curve or sketch, the entity is automatically included in Step 1.
If you select a sketch that contains more than one closed curve sequence, all closed curve sequences will be extruded. In order for a sketch to be selected, however, it must contain only closed curve sequences.
Required Step 2 
Press the Delta = field to enter the extrusion value. The value you enter is the total extrusion depth - the contour is extruded by half the value in each direction. The default direction is normal to the 2D contour or sketch plane; you can click on the arrow origin to set another direction. (In this case, flipping the arrow direction has no effect.)
Press exit
when finished. Or, if this is the final result, press OK
or Apply 
in the Feature
Guide to complete the function.
The results can be better seen in Top view. Note that extrusion value specified is the total extrusion length.
Optional Step 1 
If you want to add a draft angle to the extrusion, proceed to Optional Step 1.
When completed, the Extrude feature will appear in the Feature Tree as follows:
