Non convex hull building from a set of points

@inproceedings{BombardeRM1995a,
 abstract = { It is well known that any set of points in the 2D plane has a unique convex hull and mauy algorithms have been proposed in the litterature for building it. Conversely, the probleme of extracting a non convex hull has au infinity of solutions and, probably for this reason, has not been really studied up ta now. However, if we ask ta severa] persons ta surround the set of points with a non convex hull then, provided that the set of points is enough dense, all these persans will draw approximately the same curve! In this paper, we present a method for producing such a non convex curve. },
 author = { Bombarde, Sebastien AND Longchamp, Marc },
 booktitle = { 11th gOcad Meeting },
 month = { "june" },
 publisher = { ASGA },
 title = { Non convex hull building from a set of points },
 year = { 1995 }
}