docs: public TrajectoryEnvelope[] getRootTrajectoryEnvelopes() {
  		ArrayList<TrajectoryEnvelope> ret = new ArrayList<TrajectoryEnvelope>();
  		for (Variable var : this.getVariables()) {
  			TrajectoryEnvelope te = (TrajectoryEnvelope)var;
  			if (!te.hasSuperEnvelope()) ret.add(te);
  		}
  		return ret.toArray(new TrajectoryEnvelope[ret.size()]);
  	}