Summary: The radii used in FilletEdge can not be so large that they overlap each other and completely consume any surface they are following. This tutorials shows what to do when the surfaces overlap.
|Original polysurface. The red arrows idicate the two edges to be filleted. They are close enough together that the surfaces to be created will overlap.|
|Use FilletEdge to fillet the two edges with a 5mm radius. Notice how the surfaces partially overlap. Additionally, one of the other surfaces was lost in the FilletEdge process.|