Hi Lang,

> As you can see from the screen shot it will fillet to some degree but still
> keeps the sharp edge and does something else funny around it..

The filleter is getting confused about how to trim the main object after the fillet surfaces have been generated.

When that happens, it still spits out the fillet surface piece by itself so that you might be able to salvage it for something. The weird looking result is when you are seeing the fillet surfaces kind of submerged inside of your original object still intact - if you hide the main object you'll be able to see the fillet surfaces by themselves and see what happened a bit easier.

In this case the fillet may not like the "seam edge" of your scooped out piece:



When you build the sweep it can be a good idea to rotate your generator curve in such a way that the seam edge of the generated surface will be all on the outside part of the swept surface, that way it will eliminate some of those additional edges here.

- Michael