public MultiPolygonList2d getTopMultiPolygons() { MultiPolygonList2d mp = new MultiPolygonList2d(); Set<PolygonList2d> polygons = mp.getPolygons(); for (SplitPolygon s : this.splitPolygons) { polygons.addAll(s.getTopMultiPolygons().getPolygons()); } return mp; }