Using bespoke software I have created a propeller blade aerofoil which is imported into 2018 Inventor as an STL file. The file opens perfectly in an STL viewer (STL View) and I have checked that all face normals etc are correct. The airfoil opens perfectly into Inventor and is then converted into a Part by convert the mesh to a Base Feature. The propeller hub is created as a 2D sketch and revolved in the normal way and saved as a Part. The two parts are assembled into an Assembly by Placing and Constraining, with the final aim of applying a fillet around the foil/hub interface. The Assembly is then converted to a combined part before trying to apply the Fillet. See screen shots below of the Parts and assembly .
However I cannot make this work. I have tried Combining, Joining, Shrink Wrapping and Repairing etc. with no avail. Does anyone have a solution please??