diff --git a/include/osg/KdTree b/include/osg/KdTree
index 19b9fed22..24d1995e0 100644
--- a/include/osg/KdTree
+++ b/include/osg/KdTree
@@ -176,10 +176,12 @@ class OSG_EXPORT KdTree : public osg::Shape
                     functor.intersect(_vertices.get(), i, tri.p0, tri.p1, tri.p2);
                 }
             }
-            else if (functor.intersect(node.bb))
+            else if (functor.enter(node.bb))
             {
                 if (node.first>0) intersect(functor, _kdNodes[node.first]);
                 if (node.second>0) intersect(functor, _kdNodes[node.second]);
+
+                functor.leave();
             }
         }
 
diff --git a/include/osg/Polytope b/include/osg/Polytope
index aa3d10097..c3dceceb3 100644
--- a/include/osg/Polytope
+++ b/include/osg/Polytope
@@ -390,8 +390,8 @@ class OSG_EXPORT Polytope
                 if (_resultMask&selector_mask)
                 {
                     itr->transformProvidingInverse(matrix);
-                    selector_mask <<= 1;
                 }
+                selector_mask <<= 1;
             }
         }
 
diff --git a/src/osg/Polytope.cpp b/src/osg/Polytope.cpp
index 65e876af2..69473caa7 100644
--- a/src/osg/Polytope.cpp
+++ b/src/osg/Polytope.cpp
@@ -18,9 +18,85 @@ using namespace osg;
 
 bool Polytope::contains(const osg::Vec3f& v0, const osg::Vec3f& v1, const osg::Vec3f& v2) const
 {
-    if (contains(v0)) return true;
-    if (contains(v1)) return true;
-    if (contains(v2)) return true;
+    if (!_maskStack.back()) return true;
 
-    return false;
+    // initialize the set of vertices to test.
+    typedef std::vector<osg::Vec3d> Vertices;
+
+    Vertices src, dest;
+    src.reserve(4+_planeList.size());
+    dest.reserve(4+_planeList.size());
+
+    src.push_back(v0);
+    src.push_back(v1);
+    src.push_back(v2);
+    src.push_back(v0);
+
+    ClippingMask resultMask = _maskStack.back();
+    ClippingMask selector_mask = 0x1;
+
+    for(PlaneList::const_iterator pitr = _planeList.begin();
+        pitr != _planeList.end();
+        ++pitr)
+    {
+        if (resultMask&selector_mask)
+        {
+            //OSG_NOTICE<<"Polytope::contains() Plane testing"<<std::endl;
+
+            dest.clear();
+
+            const osg::Plane& plane = *pitr;
+            Vertices::iterator vitr = src.begin();
+
+            osg::Vec3d* v_previous = &(*(vitr++));
+            double d_previous = plane.distance(*v_previous);
+
+            for(; vitr != src.end(); ++vitr)
+            {
+                osg::Vec3d* v_current = &(*vitr);
+                double d_current = plane.distance(*v_current);
+
+                if (d_previous>=0.0)
+                {
+                    dest.push_back(*v_previous);
+
+                }
+
+                if (d_previous*d_current<0.0)
+                {
+                    // edge crosses plane so insert the vertex between them.
+                    double distance = d_previous-d_current;
+                    double r_current = d_previous/distance;
+                    osg::Vec3d v_new = (*v_previous)*(1.0-r_current) + (*v_current)*r_current;
+                    dest.push_back(v_new);
+                }
+
+                d_previous = d_current;
+                v_previous = v_current;
+
+            }
+
+            if (d_previous>=0.0)
+            {
+                dest.push_back(*v_previous);
+            }
+
+            if (dest.size()<=1)
+            {
+                // OSG_NOTICE<<"Polytope::contains() All points on triangle culled, dest.size()="<<dest.size()<<std::endl;
+                return false;
+            }
+
+            dest.swap(src);
+        }
+        else
+        {
+            // OSG_NOTICE<<"Polytope::contains() Plane disabled"<<std::endl;
+        }
+
+        selector_mask <<= 1;
+    }
+
+    //OSG_NOTICE<<"Polytope::contains() triangle within Polytope, src.size()="<<src.size()<<std::endl;
+    return true;
 }
diff --git a/src/osgUtil/PolytopeIntersector.cpp b/src/osgUtil/PolytopeIntersector.cpp
index 62965b225..f50a810a7 100644
--- a/src/osgUtil/PolytopeIntersector.cpp
+++ b/src/osgUtil/PolytopeIntersector.cpp
@@ -596,9 +596,22 @@ struct IntersectFunctor
 
     typedef std::vector<Hit> Hits;
 
-    bool intersect(const osg::BoundingBox& bb)
+    bool enter(const osg::BoundingBox& bb)
     {
-        return _polytopeIntersector->getPolytope().contains(bb);
+        if (_polytopeIntersector->getPolytope().contains(bb))
+        {
+            _polytopeIntersector->getPolytope().pushCurrentMask();
+            return true;
+        }
+        else
+        {
+            return false;
+        }
+    }
+
+    void leave()
+    {
+        _polytopeIntersector->getPolytope().popCurrentMask();
     }
 
     bool intersect(const osg::Vec3Array* vertices, int i, unsigned int p0, unsigned int p1, unsigned int p2)