diff --git a/include/osg/LOD b/include/osg/LOD
index 732de9819..35a3aa917 100644
--- a/include/osg/LOD
+++ b/include/osg/LOD
@@ -61,7 +61,8 @@ class OSG_EXPORT LOD : public Group
         enum CenterMode
         {
             USE_BOUNDING_SPHERE_CENTER,
-            USER_DEFINED_CENTER
+            USER_DEFINED_CENTER,
+            UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED
         };
 
         /** Set how the center of object should be determined when computing which child is active.*/
@@ -72,10 +73,10 @@ class OSG_EXPORT LOD : public Group
 
         /** Sets the object-space point which defines the center of the osg::LOD.  
             center is affected by any transforms in the hierarchy above the osg::LOD.*/
-        inline void setCenter(const vec_type& center) { _centerMode=USER_DEFINED_CENTER; _userDefinedCenter = center; }
+        inline void setCenter(const vec_type& center) { if (_centerMode!=UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED) { _centerMode=USER_DEFINED_CENTER; } _userDefinedCenter = center; }
         
         /** return the LOD center point. */
-        inline const vec_type& getCenter() const { if (_centerMode==USER_DEFINED_CENTER) return _userDefinedCenter; else return getBound().center(); }
+        inline const vec_type& getCenter() const { if ((_centerMode==USER_DEFINED_CENTER)||(_centerMode==UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED)) return _userDefinedCenter; else return getBound().center(); }
 
 
         /** Set the object-space reference radius of the volume enclosed by the LOD. 
@@ -85,8 +86,6 @@ class OSG_EXPORT LOD : public Group
         /** Get the object-space radius of the volume enclosed by the LOD.*/
         inline value_type getRadius() const { return _radius; }
 
-
-
         /** Modes that control how the range values should be interpreted when computing which child is active.*/
         enum RangeMode
         {
diff --git a/include/osg/ProxyNode b/include/osg/ProxyNode
index a9d5c233e..8a54aabc9 100644
--- a/include/osg/ProxyNode
+++ b/include/osg/ProxyNode
@@ -75,7 +75,8 @@ class OSG_EXPORT ProxyNode : public Group
         enum CenterMode
         {
             USE_BOUNDING_SPHERE_CENTER,
-            USER_DEFINED_CENTER
+            USER_DEFINED_CENTER,
+            UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED
         };
 
         /** Set how the center of object should be determined when computed which child is active.*/
@@ -100,10 +101,10 @@ class OSG_EXPORT ProxyNode : public Group
 
         /** Sets the object-space point which defines the center of the osg::ProxyNode.  
             center is affected by any transforms in the hierarchy above the osg::ProxyNode.*/
-        inline void setCenter(const Vec3& center) { _centerMode=USER_DEFINED_CENTER; _userDefinedCenter = center; }
+        inline void setCenter(const vec_type& center) { if (_centerMode!=UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED) { _centerMode=USER_DEFINED_CENTER; } _userDefinedCenter = center; }
         
         /** return the ProxyNode center point. */
-        inline const vec_type& getCenter() const { if (_centerMode==USER_DEFINED_CENTER) return _userDefinedCenter; else return getBound().center(); }
+        inline const vec_type& getCenter() const { if ((_centerMode==USER_DEFINED_CENTER)||(_centerMode==UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED)) return _userDefinedCenter; else return getBound().center(); }
 
 
         /** Set the object-space reference radius of the volume enclosed by the ProxyNode. 
diff --git a/src/osg/LOD.cpp b/src/osg/LOD.cpp
index 61fdb676a..a3362ebcd 100644
--- a/src/osg/LOD.cpp
+++ b/src/osg/LOD.cpp
@@ -90,6 +90,14 @@ BoundingSphere LOD::computeBound() const
     {
         return BoundingSphere(_userDefinedCenter,_radius);
     }
+    else if (_centerMode==UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED && _radius>=0.0f)
+    {
+        BoundingSphere bs = BoundingSphere(_userDefinedCenter,_radius);
+        bs.expandBy(Group::computeBound());
+        //alternative (used in TxpPagedLOD)
+        // bs.expandRadiusBy(Group::computeBound());
+        return bs;
+    }
     else
     {
         return Group::computeBound();
diff --git a/src/osg/ProxyNode.cpp b/src/osg/ProxyNode.cpp
index d6432022b..57904256e 100644
--- a/src/osg/ProxyNode.cpp
+++ b/src/osg/ProxyNode.cpp
@@ -110,6 +110,14 @@ BoundingSphere ProxyNode::computeBound() const
     {
         return BoundingSphere(_userDefinedCenter,_radius);
     }
+    else if (_centerMode==UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED && _radius>=0.0f)
+    {
+        BoundingSphere bs = BoundingSphere(_userDefinedCenter,_radius);
+        bs.expandBy(Group::computeBound());
+        //alternative (used in TxpPagedLOD)
+        // bs.expandRadiusBy(Group::computeBound());
+        return bs;
+    }
     else
     {
         return Group::computeBound();
diff --git a/src/osgPlugins/dae/daeWSceneObjects.cpp b/src/osgPlugins/dae/daeWSceneObjects.cpp
index fa05bcc17..adaa515e6 100644
--- a/src/osgPlugins/dae/daeWSceneObjects.cpp
+++ b/src/osgPlugins/dae/daeWSceneObjects.cpp
@@ -289,7 +289,7 @@ void daeWriter::apply( osg::LOD &node )
         domTechnique *teq = daeSafeCast<domTechnique>(extra->add( COLLADA_ELEMENT_TECHNIQUE ) );
         teq->setProfile( "OpenSceneGraph" );
 
-        if (node.getCenterMode()==osg::LOD::USER_DEFINED_CENTER)
+        if ((node.getCenterMode()==osg::LOD::USER_DEFINED_CENTER)||(node.getCenterMode()==osg::LOD::UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED))
         {
             domAny *center = (domAny*)teq->add("Center");
             center->setValue(toString(node.getCenter()).c_str());
diff --git a/src/osgWrappers/serializers/osg/LOD.cpp b/src/osgWrappers/serializers/osg/LOD.cpp
index 47b0d10d8..e042962e4 100644
--- a/src/osgWrappers/serializers/osg/LOD.cpp
+++ b/src/osgWrappers/serializers/osg/LOD.cpp
@@ -6,7 +6,7 @@
 // _userDefinedCenter, _radius
 static bool checkUserCenter( const osg::LOD& node )
 {
-    return node.getCenterMode()==osg::LOD::USER_DEFINED_CENTER;
+    return (node.getCenterMode()==osg::LOD::USER_DEFINED_CENTER)||(node.getCenterMode()==osg::LOD::UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED);
 }
 
 static bool readUserCenter( osgDB::InputStream& is, osg::LOD& node )
@@ -63,6 +63,7 @@ REGISTER_OBJECT_WRAPPER( LOD,
     BEGIN_ENUM_SERIALIZER( CenterMode, USE_BOUNDING_SPHERE_CENTER );
         ADD_ENUM_VALUE( USE_BOUNDING_SPHERE_CENTER );
         ADD_ENUM_VALUE( USER_DEFINED_CENTER );
+        ADD_ENUM_VALUE( UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED );
     END_ENUM_SERIALIZER();  // _centerMode
     
     ADD_USER_SERIALIZER( UserCenter );  // _userDefinedCenter, _radius
diff --git a/src/osgWrappers/serializers/osg/ProxyNode.cpp b/src/osgWrappers/serializers/osg/ProxyNode.cpp
index a82991920..bfee2cd98 100644
--- a/src/osgWrappers/serializers/osg/ProxyNode.cpp
+++ b/src/osgWrappers/serializers/osg/ProxyNode.cpp
@@ -80,7 +80,7 @@ static bool writeChildren( osgDB::OutputStream& os, const osg::ProxyNode& node )
 // _userDefinedCenter, _radius
 static bool checkUserCenter( const osg::ProxyNode& node )
 {
-    return node.getCenterMode()==osg::ProxyNode::USER_DEFINED_CENTER;
+    return (node.getCenterMode()==osg::ProxyNode::USER_DEFINED_CENTER)||(node.getCenterMode()==osg::ProxyNode::UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED);
 }
 
 static bool readUserCenter( osgDB::InputStream& is, osg::ProxyNode& node )
@@ -117,6 +117,7 @@ REGISTER_OBJECT_WRAPPER( ProxyNode,
     BEGIN_ENUM_SERIALIZER( CenterMode, USE_BOUNDING_SPHERE_CENTER );
         ADD_ENUM_VALUE( USE_BOUNDING_SPHERE_CENTER );
         ADD_ENUM_VALUE( USER_DEFINED_CENTER );
+        ADD_ENUM_VALUE( UNION_OF_BOUNDING_SPHERE_AND_USER_DEFINED );
     END_ENUM_SERIALIZER();  // _centerMode
     
     ADD_USER_SERIALIZER( UserCenter );  // _userDefinedCenter, _radius