This option allows you to impose limits and shape to the fillet you are creating. This is done by selecting line, circles, arcs and curves to define the boundary of a fillet.

Select the Fillet tool.
Select the object to be filleted.

Select the Holdline Blend option.

Select the edge/s to be filleted.

Select Finish from the Local menu or Inspector bar.
Select the Holdline.

Editing the hold line

You can change the holdline by moving or node editing to change the variable blend. By Moving:

By Node Editng: