When you open Sketcher in Part mode, you can use the edges of the part as references for sketching new entities. A thickened entity is a double offset entity whose components are separated by a user-defined distance. As you create the thickened edge, you can add flat or circular end caps to connect the two offset entities, or you can leave them unconnected. Depending on the offset and thickness values you enter, the thickened sketch can straddle the reference edge, or both offset entities can be on one side.

When you delete a thickened edge, the corresponding reference entities are retained. If you do not use these references in the section, they are deleted when you exit Sketcher.

When you use the Thicken command, you enter a thickness dimension and an offset dimension. The resulting sketch has two strong dimensions (thickness and offset) and a reference dimension (thickness value minus offset value).