  Designs generated by density-based topology optimization (TO) exhibit jagged
and/or smeared boundaries, which forms an obstacle to their integration with
existing CAD tools. Addressing this problem by smoothing or manual design
adjustments is time-consuming and affects the optimality of TO designs. This
paper proposes a fully automated procedure to obtain unambiguous, accurate and
optimized geometries from arbitrary 3D TO results. It consists of a geometry
extraction stage using a level-set-based design description involving radial
basis functions, followed by a shape optimization stage involving local
analysis refinements near the structural boundary using the Finite Cell Method.
Well-defined bounds on basis function weights ensure that sufficient
sensitivity information is available throughout the shape optimization process.
Our approach results in highly smooth and accurate optimized geometries, and
its effectiveness is illustrated by 2D and 3D examples.
