PEDIT3D   © Schulz  
  The LISP-program PEDIT3D joins line-segments, consisting of lines, LWPolylines, polylines, circular arcs, elliptical arcs, (3d-)splines and HELIX-segments to a unique 3d-polyline, consisting of linear segments. In this version a fuzzy-factor to close gaps of 0.01 is included. Here is the free version to download; it runs from ACAD2000  
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  Please copy PEDIT3D.vlx in a directory, included in the search-path of AutoCAD - best: simply in the path, where the ACAD.EXE is located, or in the SUPPORT-directory. Then you can load the PEDIT3D by typing (load "PEDIT3D.vlx") at the command line. The program starts by typing PEDIT3D at the command line. First you have to build a selection-set, consisting of the segments to join (by clicking them). The program will analyze the line-segments, will divide them in small linear intervals and will sort them to a unique 3d-polyline. This 3d-polyline will be drawn over the single line segments of the selection set. You can prove it by typing: "MOVE" "L" to move the last drawn object. There is a version for Intellicad (BricsCAD) available too For any hints please contact me.