You can create a fillet between a set of surfaces and a 3D curve. The 3D curve can be any single wireframe object, for example, a line or a composite curve.
The next to the Primary Surfaces changes to in the Selection part of the dialog.
When the curve is selected, the changes to a next to Secondary Wireframe.
An arrow is displayed on the curve to show the side of the curve on which the fillet is created. We advise you to check the fillet by clicking the Preview button. If the fillet is on the wrong side of the curve, click the arrow on the curve and preview the fillet again.
The fillet smoothly meets the surface.