diff --git a/src/osgUtil/LineSegmentIntersector.cpp b/src/osgUtil/LineSegmentIntersector.cpp
index 04cfc8eee..7ffa743b5 100644
--- a/src/osgUtil/LineSegmentIntersector.cpp
+++ b/src/osgUtil/LineSegmentIntersector.cpp
@@ -484,20 +484,11 @@ bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
     osg::Vec3d bb_min(bbInput._min);
     osg::Vec3d bb_max(bbInput._max);
 
-#if 1
-    double epsilon = 1e-4;
-    bb_min.x() -= epsilon;
-    bb_min.y() -= epsilon;
-    bb_min.z() -= epsilon;
-    bb_max.x() += epsilon;
-    bb_max.y() += epsilon;
-    bb_max.z() += epsilon;
-#endif
+    double epsilon = 1e-6;
 
     // compate s and e against the xMin to xMax range of bb.
     if (s.x()<=e.x())
     {
-
         // trivial reject of segment wholely outside.
         if (e.x()<bb_min.x()) return false;
         if (s.x()>bb_max.x()) return false;
@@ -505,13 +496,15 @@ bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
         if (s.x()<bb_min.x())
         {
             // clip s to xMin.
-            s = s+(e-s)*(bb_min.x()-s.x())/(e.x()-s.x());
+            double r = (bb_min.x()-s.x())/(e.x()-s.x()) - epsilon;
+            if (r>0.0) s = s + (e-s)*r;
         }
 
         if (e.x()>bb_max.x())
         {
             // clip e to xMax.
-            e = s+(e-s)*(bb_max.x()-s.x())/(e.x()-s.x());
+            double r = (bb_max.x()-s.x())/(e.x()-s.x()) + epsilon;
+            if (r<1.0) e = s+(e-s)*r;
         }
     }
     else
@@ -521,21 +514,22 @@ bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
 
         if (e.x()<bb_min.x())
         {
-            // clip s to xMin.
-            e = s+(e-s)*(bb_min.x()-s.x())/(e.x()-s.x());
+            // clip e to xMin.
+            double r = (bb_min.x()-e.x())/(s.x()-e.x()) - epsilon;
+            if (r>0.0) e = e + (s-e)*r;
         }
 
         if (s.x()>bb_max.x())
         {
-            // clip e to xMax.
-            s = s+(e-s)*(bb_max.x()-s.x())/(e.x()-s.x());
+            // clip s to xMax.
+            double r = (bb_max.x()-e.x())/(s.x()-e.x()) + epsilon;
+            if (r<1.0) s = e + (s-e)*r;
         }
     }
 
     // compate s and e against the yMin to yMax range of bb.
     if (s.y()<=e.y())
     {
-
         // trivial reject of segment wholely outside.
         if (e.y()<bb_min.y()) return false;
         if (s.y()>bb_max.y()) return false;
@@ -543,13 +537,15 @@ bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
         if (s.y()<bb_min.y())
         {
             // clip s to yMin.
-            s = s+(e-s)*(bb_min.y()-s.y())/(e.y()-s.y());
+            double r = (bb_min.y()-s.y())/(e.y()-s.y()) - epsilon;
+            if (r>0.0) s = s + (e-s)*r;
         }
 
         if (e.y()>bb_max.y())
         {
             // clip e to yMax.
-            e = s+(e-s)*(bb_max.y()-s.y())/(e.y()-s.y());
+            double r = (bb_max.y()-s.y())/(e.y()-s.y()) + epsilon;
+            if (r<1.0) e = s+(e-s)*r;
         }
     }
     else
@@ -559,21 +555,22 @@ bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
 
         if (e.y()<bb_min.y())
         {
-            // clip s to yMin.
-            e = s+(e-s)*(bb_min.y()-s.y())/(e.y()-s.y());
+            // clip e to yMin.
+            double r = (bb_min.y()-e.y())/(s.y()-e.y()) - epsilon;
+            if (r>0.0) e = e + (s-e)*r;
         }
 
         if (s.y()>bb_max.y())
         {
-            // clip e to yMax.
-            s = s+(e-s)*(bb_max.y()-s.y())/(e.y()-s.y());
+            // clip s to yMax.
+            double r = (bb_max.y()-e.y())/(s.y()-e.y()) + epsilon;
+            if (r<1.0) s = e + (s-e)*r;
         }
     }
 
     // compate s and e against the zMin to zMax range of bb.
     if (s.z()<=e.z())
     {
-
         // trivial reject of segment wholely outside.
         if (e.z()<bb_min.z()) return false;
         if (s.z()>bb_max.z()) return false;
@@ -581,13 +578,15 @@ bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
         if (s.z()<bb_min.z())
         {
             // clip s to zMin.
-            s = s+(e-s)*(bb_min.z()-s.z())/(e.z()-s.z());
+            double r = (bb_min.z()-s.z())/(e.z()-s.z()) - epsilon;
+            if (r>0.0) s = s + (e-s)*r;
         }
 
         if (e.z()>bb_max.z())
         {
             // clip e to zMax.
-            e = s+(e-s)*(bb_max.z()-s.z())/(e.z()-s.z());
+            double r = (bb_max.z()-s.z())/(e.z()-s.z()) + epsilon;
+            if (r<1.0) e = s+(e-s)*r;
         }
     }
     else
@@ -597,14 +596,16 @@ bool LineSegmentIntersector::intersectAndClip(osg::Vec3d& s, osg::Vec3d& e,const
 
         if (e.z()<bb_min.z())
         {
-            // clip s to zMin.
-            e = s+(e-s)*(bb_min.z()-s.z())/(e.z()-s.z());
+            // clip e to zMin.
+            double r = (bb_min.z()-e.z())/(s.z()-e.z()) - epsilon;
+            if (r>0.0) e = e + (s-e)*r;
         }
 
         if (s.z()>bb_max.z())
         {
-            // clip e to zMax.
-            s = s+(e-s)*(bb_max.z()-s.z())/(e.z()-s.z());
+            // clip s to zMax.
+            double r = (bb_max.z()-e.z())/(s.z()-e.z()) + epsilon;
+            if (r<1.0) s = e + (s-e)*r;
         }
     }
 
@@ -619,7 +620,7 @@ osg::Texture* LineSegmentIntersector::Intersection::getTextureLookUp(osg::Vec3&
 {
     osg::Geometry* geometry = drawable.valid() ? drawable->asGeometry() : 0;
     osg::Vec3Array* vertices = geometry ? dynamic_cast<osg::Vec3Array*>(geometry->getVertexArray()) : 0;
-    
+
     if (vertices)
     {
         if (indexList.size()==3 && ratioList.size()==3)
@@ -718,7 +719,7 @@ osg::Texture* LineSegmentIntersector::Intersection::getTextureLookUp(osg::Vec3&
         }
 
         return const_cast<osg::Texture*>(activeTexture);
-        
+
     }
     return 0;
 }