I draw a simple semi circle on two planes with which I want to connect with a lofted sheet metal feature. Ok, I want to incorporate a number of bends on the semi circle, done. However, my outside diameter is incorrect. Go back into the feature to change the reference point from the radius of bend to the flat of the facet....wait...what! No reference point?! Am I overlooking something?
I want the feature to have a reference point or a relations point in which to make it tangent to the sketch, yes. Much like many of the other features do in Solidworks, such as a in a weldment profile or how the edge flange reference point does. However, adjusting the sketch to match the feature is counter intuitive. It should be the other way round. I do hear you though, and thought that at first but doing it that way makes the design very rigid. You would have to go into that features "layout" sketch and edit the sketch and probably some equations every time you wanted to change the number of bends. Very cumbersome if you have to do that for many parts in an assembly, especially if your desired design would be to have everything driven from a top down "main layout" sketch or design table. It would be nice to be able to use this feature for making bent formed tube with a set number of sides where the outside diameter is measured across flats because it creates an annotation for the number of facets you used. Which in turn, can easily be inserted into a design table for changing the number of sides on the fly. Thanks for the suggestion though.
For what you want, it sounds like you should be using a inscribed polygons in your sketch instead of circles.
If you want a conical shape, then sketch with circles and use "Formed" for your manufacturing method after you click on lofted bend.
That's exactly what i want for the feature itself. An inscribed or circumscribed option so that you can choose whether to have your outside diameter from corner to corner or from flat to flat. It frankly blows my mind that this isnt an option at all. Seems so fundamental and basic, especially if the edge flange has comparable options and an abundance of others for your sheet metal feature. However, about the polygon. Polygons do not create an annotation for the number of sides it has when you draw one. Therefore, again, isnt very intuitive when you want to easily change the number of sides from a design table or top level layout sketch. You would have to go into that part's sketch and edit the pattern of the polygon to change the number of sides. Even then, if you did, you would get errors or missing references gallore if you had had any external references to the previous polygon.
I don't think this is really what you are after, but if you click the "reverse direction" box in the sheet metal parameters then it will toggle whether the reference sketch is on the inside or outside diameter of the part. However I think what you are really asking is if you can change the bends so that the sketch runs tangent to the flats rather than tangent to the bends. I don't see a way to do that, you might need to manually adjust the radius of the sketch to compensate.