vertices.add(new Vector3(1, 2, 3));
vertices.add(new Vector3(4, 5, 6));
vertices.add(new Vector3(7, 8, 9));
final Vector3 v = new Vector3(1., 2., 3.);
final double[] d = v.toArray();
assertEquals(1., v.x);
assertEquals(2., v.y);
assertEquals(3., v.z);
assertEquals(3, d.length);
assertEquals(1., d[0]);