Lofted bends in sheet metal parts use two open profile sketches that are connected by a loft.
Solidworks sheet metal lofted bend.
To find out more about lofted bends you need to dig a little deeper into help and do a search for bent lofted bends unfortunately at this current time i am only able to find information about formed lofted bends in the solidworks training manual for sheet metal.
Begin with two open profile sketches.
The base flange feature is not used with the lofted bend feature.