m_vis.putAction("animate", animate);
m_vis.alwaysRunAfter("filter", "animate");
// visibility determiner
ActionList visibility = new ActionList();
visibility.add(new VisibilityFilter(new VisiblePredicate()));
m_vis.putAction("visibility", visibility);
visibility.alwaysRunAfter(animate);
/*// add force repulsion
ForceSimulator fsim = new ForceSimulator();