Documentation

The QuickHull library for Icy implements 2D and 3D algorithns to calculate convex envelopes from a given (random) set of points.

The 2D version of the algorithm is detailed here (see "alternative method"): https://en.wikipedia.org/wiki/Quickhull

The 3D version of the algorithm is detailed here: https://www.cs.ubc.ca/~lloyd/java/quickhull3d.html

The easiest way to use the library from within Icy is via the Convexify ROI plug-in

The low-level API can be accessed as follows:

• In 2D:

      List<Point2D> points = ...
      // replace the list by its envelope
      points = QuickHull2D.computeConvexEnvelope(points);
      // Conveniently, a region of interest is easy to create
      ROI2DPolygon polygon = new ROI2DPolygon(points);

• In 3D:

     Point3d[] points = ...
     QuickHull3D qhull3d = new QuickHull3D();
     // build the envelope (nothing is returned)
     qhull3d.build(points, points.length);
     // The envelope is built as a mesh (faces and vertices), accessible via:
     Point3d[] hullVertices = qhull3d.getVertices();
     int[][] faces = qhull3d.getVertices();
     // However, conveniently, a ROI can easily be obtained from the QuickHull3D object using
     ROI3DPolygonalMesh mesh = new ROI3DPolygonalMesh(qhull3d);