Offset Faces
Insert 
Shapes (Standard) (Part Level)
Use this command to create a new face offset
from a face at a specified distance. Multiple faces can be offset at the
same time. The required inputs include the face to offset and the distance.
Optional inputs include the ability to keep the original face and to give the new face a unique name if desired. You can also create variable offsets by controlling offset distances at selected points on the faces.
Faces - Select the faces to offset.
Offset - Specify the offset distance. You can enter a value or right-click to select additional input options such as an existing dimension value or expression. A positive or negative value determines the direction of offset.
Offset point - This option allows you to create variable offsets. Select a point on the face and then enter a variable offset distance unique to that point. The new face is fitted through the controlling offset distances honoring the default Offset above as well as any offset Points defined here.
Keep original surface - Check this box if you want to keep the original face. Otherwise it will be discarded.
