Find a boundery from set of 3d line segments

Question

I have a set of n 3d line segments [(p1_start,p1_end), (p2_start,p2_end),....(pn_start,pn_end)]. (I believe that they shod be nin-intersecting...) These segments represent a (closed) boundary. I am looking for effective algorithm to generate this boundary, i.e. to find the order of segments for boundary : [pj_start,pj_end, ...p1_start, p1_end.....] (segments can be connected via their ends: start to start , start to end, end to start, end to end) I thought to start from arbitrary segment , say s = (pm_start, pm_end), among all other segment find the one , which distance to pm_start or pm_end is minimal, and add this segment end based on calculated minimum distance and continue this way for all segments The complexity of this approach is not good Can anyone propose effective algorithm for this problem