To Fillet an Entire Polyline (AutoCAD Mechanical Toolset)

You can fillet all vertexes of a polyline at the same time.

Note: Only the segments long enough to accommodate the fillet is filleted.
  1. Click Home tabModify panelFillet. Find
  2. Enter P for polyline.
  3. On the ribbon, in the Fillet Options panel, check the fillet size. To change the fillet radius:
    1. Click <Current tab>Fillet Options panelFillet Size drop-down. Find
    2. Select the desired fillet size from the drop-down.
  4. Click an empty space in the drawing area.
  5. Select the polyline.