diff --git a/src/cgaladv.cc b/src/cgaladv.cc
index 45a3bdd3..6301cd3c 100644
--- a/src/cgaladv.cc
+++ b/src/cgaladv.cc
@@ -34,7 +34,7 @@
 #ifdef ENABLE_CGAL
 extern CGAL_Nef_polyhedron3 minkowski3(CGAL_Nef_polyhedron3 a, CGAL_Nef_polyhedron3 b);
 extern CGAL_Nef_polyhedron2 minkowski2(CGAL_Nef_polyhedron2 a, CGAL_Nef_polyhedron2 b);
-extern CGAL_Nef_polyhedron2 convexhull2(CGAL_Nef_polyhedron2 a);
+extern CGAL_Nef_polyhedron2 convexhull2(std::list<CGAL_Nef_polyhedron2> a);
 #endif
 
 enum cgaladv_type_e {
@@ -184,19 +184,24 @@ CGAL_Nef_polyhedron CgaladvNode::render_cgal_nef_polyhedron() const
 	if (type == HULL)
 	{
 
+	    std::list<CGAL_Nef_polyhedron2> polys;
+	    bool all2d = true;
 	    foreach(AbstractNode * v, children) {
 		if (v->modinst->tag_background)
 		    continue;
 		N = v->render_cgal_nef_polyhedron();
 		if (N.dim == 3) {
-
+		    //polys.push_back(tmp.p3);
+		    all2d=false;
 		}
 		if (N.dim == 2) {
-		    N.p2 = convexhull2(N.p2);
+		    polys.push_back(N.p2);
 		}
 		v->progress_report();
-		break;
 	    }
+
+	    if(all2d)
+		N.p2 = convexhull2(polys);
 	}
 
 	cgal_nef_cache.insert(cache_id, new cgal_nef_cache_entry(N), N.weight());
diff --git a/src/cgaladv_convexhull2.cc b/src/cgaladv_convexhull2.cc
index 19149543..e1e466d7 100644
--- a/src/cgaladv_convexhull2.cc
+++ b/src/cgaladv_convexhull2.cc
@@ -29,31 +29,27 @@
 #include "cgal.h"
 #include <CGAL/convex_hull_2.h>
 
-extern CGAL_Nef_polyhedron2 convexhull2(CGAL_Nef_polyhedron2 a);
+extern CGAL_Nef_polyhedron2 convexhull2(std::list<CGAL_Nef_polyhedron2> a);
 extern CGAL_Poly2 nef2p2(CGAL_Nef_polyhedron2 p);
 
-static std::list<CGAL_Nef_polyhedron2::Point> p2points(CGAL_Poly2 p2)
+CGAL_Nef_polyhedron2 convexhull2(std::list<CGAL_Nef_polyhedron2> a)
 {
-	std::list<CGAL_Nef_polyhedron2::Point> points;
-	for (int j = 0; j < p2.size(); j++) {
-		double x = to_double(p2[j].x()), y = to_double(p2[j].y());
-		CGAL_Nef_polyhedron2::Point p =
-		CGAL_Nef_polyhedron2::Point(x, y);
-		points.push_back(p);
+    std::list<CGAL_Nef_polyhedron2::Point> points;
+
+    std::list<CGAL_Nef_polyhedron2>::iterator i;
+    for(i=a.begin(); i!=a.end(); i++) {
+	CGAL_Poly2 ap=nef2p2(*i);
+	for (int j=0;j<ap.size();j++) {
+	    double x=to_double(ap[j].x()),y=to_double(ap[j].y());
+	    CGAL_Nef_polyhedron2::Point p=CGAL_Nef_polyhedron2::Point(x,y);
+	    points.push_back(p);
 	}
-	return points;
-}
+    }
 
-CGAL_Nef_polyhedron2 convexhull2(CGAL_Nef_polyhedron2 a)
-{
-    CGAL_Poly2 ap = nef2p2(a);
-    std::list<CGAL_Nef_polyhedron2::Point> points = p2points(ap), result;
+    std::list<CGAL_Nef_polyhedron2::Point> result;
+    CGAL::convex_hull_2(points.begin(),points.end(),std::back_inserter(result));
 
-    CGAL::convex_hull_2(points.begin(), points.end(),
-    std::back_inserter(result));
-		std::cout << result.size() << " points on the convex hull" << std::endl;
-                return CGAL_Nef_polyhedron2(result.begin(),
-    result.end(), CGAL_Nef_polyhedron2::INCLUDED);
+    return CGAL_Nef_polyhedron2(result.begin(),result.end(),CGAL_Nef_polyhedron2::INCLUDED);
 }
 
 #endif