Use the controls in the Surface Fillet option window to control the shape (cross section) of a fillet surface.
Choose Surfaces > Multi-Surface Fillet > Surface Fillet to show the fillet control window.
Use a circular cross-section with lead in
The Tangent Offset is the distance between the intersection line of the two sets of surfaces and the contact lines (the lines along which the new fillet surface touches the surfaces on either side).
Since the two numbers are two different ways of measuring the lead distance, it does not matter which way you prefer to specify it.
The Peak Radius is the minimum radius that the fillet is allowed to have at the top.
The Knee Ratio is the ratio between the peak radius and the tangent offset distance. Knee ratio = peak radius divided by tangent offset.
Use a lead-in cross-section with bias
The Tangent Offset is the distance between the intersection line of the two sets of surfaces and the contact lines (the lines along which the new fillet surface touches the surfaces on either side).
Since the two numbers are two different ways of measuring the lead distance, it does not matter which way you prefer to specify it.
The Peak Radius is the minimum radius that the fillet is allowed to have at the top.
The Knee Ratio is the ratio between the peak radius and the tangent offset distance. Knee ratio = peak radius divided by tangent offset.
The Center Radius is the radius at the arclength center of the fillet.
The Tangent Offset is the distance between the intersection line of the two sets of surfaces and the contact lines (the lines along which the new fillet surface touches the surfaces on either side).