Edit NURBS > Surface Fillet > Freeform Fillet

Creates a fillet surface with configurable bias between two existing surfaces.

Edit NURBS > Surface Fillet > Freeform Fillet >

Bias: The Bias value scales the end tangents across the two surface curves.
Depth: The Depth value controls the curvature of the filleted surface.
Use Tolerance: The Use Tolerance options let you reapply a free-form fillet within a specified tolerance value.

Global tolerance causes Maya to use the Positional and Tangential values from the Settings part of the Preferences window.

Local tolerance lets you enter a new value to override the values in the Preferences window.
Output Geometry: Specifies the type of geometry created. (Subdiv means subdivision surfaces.)