Problem with fillet

I am trying to fillet an edge. when i do it leaves an open spot and now it is not water tight. how do i do keep it as a solid?
test2.3dm (2.3 MB)

The problem is the flat surface is above the fillet after creating the fillet between the curved, outer surface and the vertical surface. Several ways to fix the problem:

  • Lower the flat surface.
  • Replace the flat surface with a curve surface which is below the fillet for the entire perimeter.
  • Use a much smaller radius fillet. You may need to experiment to determine how small is needed.
  • Use a variable radius fillet with a smaller fillet in the are needed to keep the fillet above the flat area. Explode the surfaces, then VariableFilletSrf

You need to decide which result is closest to your design intent.

thanks! I will try the VariableFilletSrf.