The Check Closing function allows you to correct polylines that were not closed properly. In creating a polyline, you can actually draw a segment back to the point of beginning, which creates a geometrically closed polyline. However, AutoCAD reports this as an open polyline and several operations such as OFFSET will yield undesirable results. This function evaluates the selection set of polylines, removes the closing segment, and sets the closed flag. This not only corrects problems, it reduces file size by removing one vertex.
Keyboard Command: PlnClsChk