smooth();
physics = new VerletPhysics3D();
// physics.addBehavior(new GravityBehavior(new Vec3D(0, 0.2f, 0),
// 0.6f));
Vec3D stepDir = new Vec3D(1, 0, 0).normalizeTo(REST_LENGTH);
ParticleString3D s = new ParticleString3D(physics, new Vec3D(), stepDir,
NUM_PARTICLES, 1, 0.1f);
head = s.getHead();
head.lock();
tail = s.getTail();
physics.addBehavior(new AttractionBehavior3D(new Vec3D(), 400, 0.5f));
}