FILLET command
Fillets intersections; joins intersecting lines with an arc of any suitable radius.
                Icon: 
Alias: F
Description
Sets a radius value for fillet between two entities.
The entities could be:
- Lines, including parallel lines
 - All vertices of a single 2D polyline; two polylines cannot be filleted
 - Rays, including parallel rays
 - Infinite lines, including parallel infinite lines
 - Arcs
 
Note: Press and hold the Shift key when select the second
                    entity to create a corner (radius = 0). The selected entities are extended or
                    trimmed at the intersection point. The selected part of the entities is
                    kept.
            Note: If the second entity is parallel to the first entity the
                    entities are connected by a semicircle. If the parallel entities are not of
                    equal length, then the second entity is extended or trimmed when Trim Mode =
                    Trim.
            Options
- fillet Settings
 - Displays the Chamfer/Fillet section of the Settings dialog box:
 
- Polyline
 - Fillets the all vertices of a polyline.
 
- Radius
 - Toggles edge mode.
 
- Trim
 - Sets the trim mode for chamfers and fillets:
 
- Undo
 - Undoes the last fillet when in Multiple mode.
 
- Multiple
 - Lets to create additional fillets using the same settings without having to restart the command.