AutoLISP to create a closed boundary outline from a wide LWPolyline

 If you've ever needed to generate a clean outer silhouette or outline of an LWPolyline that has a wide width (or dynamically changing widths along its vertices), you know it can be a pain to trace manually

Here is a quick, native AutoLISP utility that does the math for you. It reads the local segment angles, calculates the perpendicular offset requirements for each individual vertex, and generates a new, closed LWPolyline right over the outer envelope.

download this lisp  Polyline Outline