static class DiscAction extends AbstractNodeAction {
@Override
public void actionPerformed(ActionEvent e) {
DiscDialog d=new DiscDialog(
javax.swing.SwingUtilities.getWindowAncestor( getNode().getTree()),
getLocation(),"Disc"); // TODO i18n
DiscDialog.Result n=d.getResult();
if(n!=null){
GroupNode gn=(GroupNode)getNode();
Shape3D sd= new Shape3D(Geometries.disc(n.radius, n.divisions,n.up,0.));
Color3f aColor = new Color3f(0.1f, 0.1f, 0.1f);