Constant Radius FilletKeyCreator \ Create \ Advanced-Surfaces \ Constant-Radius-Fillet
Location: Create>Advanced Surfaces>Constant Radius Fillet
The Constant Radius Fillet option can be used to automatically construct fillet surfaces. A fillet surface is one that smoothly blends between two surfaces with a radial (circular arc) profile.
It could be thought of as the area swept out by a rolling ball touching both surfaces simultaneously. This technique uses a different algorithm than Solid edge blending and is typically used when the geometry to be modified is a surface model (not a Solid model), and stitching it into a solid model is impractical.