Frequent tipster Danny Korem discusses using the Fillet command in AutoCAD to join polylines.
"You have created some linework, and now you have decided to turn it all into a closed polyline. Parts of the linework are already polylines; parts are lines. You can use the Edit Polyline option and opt for the Join option, but you can also fillet polylines and lines. The magic is that when filleted, polylines and/or lines are joined to the first selection.
"The advantages are:
Join won't help if two endpoints are not coincident, but fillet will.
The number of clicks while using the Pedit command session is relatively higher.
Sometimes the 'closed' 'yes' property of the polyline will help close it, but it won't necessarily catch the design intent.
Two polylines before filleting, one polyline after filleting."
Notes from Cadalyst tip reviewer Brian Benton: Polylines are objects made up of segments; some segments are lines and others are arcs. Users can create a polyline from other objects using the PEdit command.
You can also join objects to a polyline using the Join command or Join option in the PEdit (Polyline Edit) command, but it can be tricky. The endpoints of the segments you want to join have to be coincident, or at the same x,y,z coordinate. You can use the Fuzz option, which will draw a segment between the two segment points when using the Join tool. That can help, but you have to manage the extra segments that are created, and that can be a hassle.
Using the Fillet command creates a fillet between the line and polyline segment. It creates an arc at the defined radius and adjusts the segments as needed. It also adds the line and the fillet radius to the polyline.