diff --git a/include/osgVolume/RayTracedTechnique b/include/osgVolume/RayTracedTechnique
index 58ab6bbba..1d3da73a4 100644
--- a/include/osgVolume/RayTracedTechnique
+++ b/include/osgVolume/RayTracedTechnique
@@ -47,7 +47,7 @@ class OSGVOLUME_EXPORT RayTracedTechnique : public VolumeTechnique
 
         osg::ref_ptr<osg::MatrixTransform> _transform;
 
-        typedef std::map<osgUtil::CullVisitor*, osg::Matrix> ModelViewMatrixMap;
+        typedef std::map<osgUtil::CullVisitor::Identifier*, osg::Matrix> ModelViewMatrixMap;
 
         OpenThreads::Mutex _mutex;
         ModelViewMatrixMap _modelViewMatrixMap;
diff --git a/src/osgVolume/RayTracedTechnique.cpp b/src/osgVolume/RayTracedTechnique.cpp
index 14d9c7eee..857e05d96 100644
--- a/src/osgVolume/RayTracedTechnique.cpp
+++ b/src/osgVolume/RayTracedTechnique.cpp
@@ -553,7 +553,7 @@ void RayTracedTechnique::cull(osgUtil::CullVisitor* cv)
         bool moving = false;
         {
             OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
-            ModelViewMatrixMap::iterator itr = _modelViewMatrixMap.find(cv);
+            ModelViewMatrixMap::iterator itr = _modelViewMatrixMap.find(cv->getIdentifier());
             if (itr!=_modelViewMatrixMap.end())
             {
                 osg::Matrix newModelViewMatrix = *(cv->getModelViewMatrix());
@@ -564,7 +564,7 @@ void RayTracedTechnique::cull(osgUtil::CullVisitor* cv)
             }
             else
             {
-                _modelViewMatrixMap[cv] = *(cv->getModelViewMatrix());
+                _modelViewMatrixMap[cv->getIdentifier()] = *(cv->getModelViewMatrix());
             }
         }