Combining Contours

Heya All,

I want the total contour of a mesh as if viewing from top-down on the z axis.  I grab a contour every 1 mm on the z axis, and then move all points to 0 z-axis.  Is there a method to contour around these points?

private void AddContours(MeshGeometry3D mesh)
        {
            //abort if the mesh is invalid
            if (mesh == null || mesh.TriangleIndices.Count < 3)
                return;

            var bounds = mesh.Bounds;

            List<Point3D> pointmap = new List<Point3D>(); //collects all the points from contouring

            //setting the contour plane

            Point3D plane = new Point3D();
            Vector3D normal = new Vector3D(0,0,1);

            //cycles through the mesh, grabbing a contour at each z interval
            //combines all on 0 on the z-axis
            for (double z = 0.1; z < bounds.SizeZ; z += 0.1)
            {
                plane = new Point3D(0, 0, z);
                var segments = MeshGeometryHelper.GetContourSegments(mesh, plane, normal).ToList(); //calculates the contour 

                foreach (var point in segments)
                   pointmap.Add(new Point3D(point.X, point.Y, 0));
            }

           //convert pointmap to a contour

           //done converting contour

            var mb = new MeshBuilder(true, false);
            mb.CreateNormals = false;
            mb.AddPolygon(contour);
            
            var model = mb.ToMesh();

            DisplayModel();
        }