diff --git a/src/osgUtil/CullVisitor.cpp b/src/osgUtil/CullVisitor.cpp
index 86d3a8993..70c6722c3 100644
--- a/src/osgUtil/CullVisitor.cpp
+++ b/src/osgUtil/CullVisitor.cpp
@@ -218,16 +218,16 @@ void CullVisitor::popProjectionMatrix()
         // so it doesn't cull them out.
         osg::Matrix& projection = *_projectionStack.back();
 
-        double desired_znear = _computed_znear*0.95;
-        double desired_zfar = _computed_zfar*1.05;
+        double desired_znear = _computed_znear;
+        double desired_zfar = _computed_zfar;
 
         double min_near_plane = _computed_zfar*0.0005f;
         if (desired_znear<min_near_plane) desired_znear=min_near_plane;
 
-        double trans_near_plane = (-desired_znear*projection(0,2)-desired_znear*projection(1,2)-desired_znear*projection(2,2)+projection(3,2))/(-desired_znear*projection(2,3));
-        double trans_far_plane = (-desired_zfar*projection(0,2)-desired_zfar*projection(1,2)-desired_zfar*projection(2,2)+projection(3,2))/(-desired_zfar*projection(2,3));
+        double trans_near_plane = (-desired_znear*projection(2,2)+projection(3,2))/(-desired_znear*projection(2,3)+projection(3,3));
+        double trans_far_plane = (-desired_zfar*projection(2,2)+projection(3,2))/(-desired_zfar*projection(2,3)+projection(3,3));
 
-        double ratio = fabs(2.0f/(trans_near_plane-trans_far_plane));
+        double ratio = fabs(2.0f/(trans_near_plane-trans_far_plane))*0.95;
         double center = -(trans_near_plane+trans_far_plane)/2.0f;
 
         projection.postMult(osg::Matrix(1.0f,0.0f,0.0f,0.0f,
diff --git a/src/osgUtil/TrackballManipulator.cpp b/src/osgUtil/TrackballManipulator.cpp
index d2f88e988..622aff526 100644
--- a/src/osgUtil/TrackballManipulator.cpp
+++ b/src/osgUtil/TrackballManipulator.cpp
@@ -143,6 +143,13 @@ bool TrackballManipulator::handle(const GUIEventAdapter& ea,GUIActionAdapter& us
                 _camera->setFusionDistanceRatio(_camera->getFusionDistanceRatio()/1.25f);
                 return true;
             }
+// this is quick hack to test out othographic projection.            
+//             else if (ea.getKey()=='O')
+//             {
+//                 float dist = _camera->getLookDistance();
+//                 _camera->setOrtho(-dist,dist,-dist,dist,-dist,dist);
+//                 return true;
+//             }
             return false;
         case(GUIEventAdapter::FRAME):
             _camera->setFusionDistanceMode(osg::Camera::PROPORTIONAL_TO_LOOK_DISTANCE);