Qhull computes convex hulls, Delaunay triangulations, halfspace
intersections about a point, Voronoi diagrams, furthest-site Delaunay
triangulations, and furthest-site Voronoi diagrams. It runs in 2-d,
3-d, 4-d, and higher dimensions. It implements the Quickhull algorithm
for computing the convex hull. Qhull handles roundoff errors from
floating point arithmetic. It computes volumes, surface areas, and
approximations to the convex hull.

WWW: http://www.qhull.org