diff --git a/include/osg/CullSettings b/include/osg/CullSettings
index 528fe6d52..46d0f327b 100644
--- a/include/osg/CullSettings
+++ b/include/osg/CullSettings
@@ -1,4 +1,4 @@
-/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2003 Robert Osfield 
+/* -*-c++-*- OpenSceneGraph - setCullSettingsright (C) 1998-2003 Robert Osfield 
  *
  * This library is open source and may be redistributed and/or modified under  
  * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
@@ -19,13 +19,29 @@
 
 namespace osg {
 
+// forward declare
+class ArgumentParser;
+class ApplicationUsage;
+
 class SG_EXPORT CullSettings
 {
     public:
 
-        CullSettings() { setDefaults(); }
+        CullSettings()
+        {
+            setDefaults();
+            readEnvironmentalVariables();
+        }
+
+        CullSettings(ArgumentParser& arguments)
+        {
+            setDefaults();
+            readEnvironmentalVariables();
+            readCommandLine(arguments);
+        }
+
+        CullSettings(const CullSettings& cs);
 
-        CullSettings(const CullSettings& cs) { setCullSettings(cs); }
         ~CullSettings() {}
         
         CullSettings& operator = (const CullSettings& settings)
@@ -35,9 +51,16 @@ class SG_EXPORT CullSettings
             return *this;
         }
 
-        void setDefaults();
-        
         void setCullSettings(const CullSettings& settings);
+        
+        void setDefaults();
+
+        /** read the environmental variables.*/
+        void readEnvironmentalVariables();
+
+        /** read the commandline arguments.*/
+        void readCommandLine(ArgumentParser& arguments);
+
 
         /** Switch the creation of Impostors on or off.
           * Setting active to false forces the CullVisitor to use the Impostor
diff --git a/include/osg/DisplaySettings b/include/osg/DisplaySettings
index 92f4a8a6c..ec62ffa33 100644
--- a/include/osg/DisplaySettings
+++ b/include/osg/DisplaySettings
@@ -54,11 +54,13 @@ class SG_EXPORT DisplaySettings : public osg::Referenced
 
         DisplaySettings& operator = (const DisplaySettings& vs);
  
+        void setDisplaySettings(const DisplaySettings& vs);
         
         void merge(const DisplaySettings& vs);
 
         void setDefaults();
         
+        /** read the environmental variables.*/
         void readEnvironmentalVariables();
 
         /** read the commandline arguments.*/
@@ -166,7 +168,6 @@ class SG_EXPORT DisplaySettings : public osg::Referenced
     
         virtual ~DisplaySettings();
 
-        void copy(const DisplaySettings& vs);
 
         DisplayType                     _displayType;
         bool                            _stereo;
diff --git a/src/osg/CullSettings.cpp b/src/osg/CullSettings.cpp
index 645302a64..daecf4b5d 100644
--- a/src/osg/CullSettings.cpp
+++ b/src/osg/CullSettings.cpp
@@ -12,9 +12,18 @@
 */
 
 #include <osg/CullSettings>
+#include <osg/ArgumentParser>
+#include <osg/ApplicationUsage>
+
+#include <osg/Notify>
 
 using namespace osg;
 
+CullSettings::CullSettings(const CullSettings& cs)
+{
+    setCullSettings(cs);
+}
+
 void CullSettings::setDefaults()
 {
     _cullingMode = DEFAULT_CULLING;
@@ -51,3 +60,60 @@ void CullSettings::setCullSettings(const CullSettings& settings)
     _LODScale = settings._LODScale;
     _smallFeatureCullingPixelSize = settings._smallFeatureCullingPixelSize;
 }
+
+static ApplicationUsageProxy ApplicationUsageProxyCullSettings_e0(ApplicationUsage::ENVIRONMENTAL_VARIABLE,"OSG_COMPUTE_NEAR_FAR_MODE <mode>","DO_NOT_COMPUTE_NEAR_FAR | COMPUTE_NEAR_FAR_USING_BOUNDING_VOLUMES | COMPUTE_NEAR_FAR_USING_PRIMITIVES");
+static ApplicationUsageProxy ApplicationUsageProxyCullSettings_e1(ApplicationUsage::ENVIRONMENTAL_VARIABLE,"OSG_NEAR_FAR_RATIO <float>","Set the ratio between near and far planes - must greater than 0.0 but less than 1.0.");
+
+void CullSettings::readEnvironmentalVariables()
+{
+    osg::notify(osg::INFO)<<"CullSettings::readEnvironmentalVariables()"<<std::endl;
+
+    char *ptr;
+    
+    if ((ptr = getenv("OSG_COMPUTE_NEAR_FAR_MODE")) != 0)
+    {
+        if (strcmp(ptr,"DO_NOT_COMPUTE_NEAR_FAR")==0) _computeNearFar = DO_NOT_COMPUTE_NEAR_FAR;
+        else if (strcmp(ptr,"COMPUTE_NEAR_FAR_USING_BOUNDING_VOLUMES")==0) _computeNearFar = COMPUTE_NEAR_FAR_USING_BOUNDING_VOLUMES;
+        else if (strcmp(ptr,"COMPUTE_NEAR_FAR_USING_PRIMITIVES")==0) _computeNearFar = COMPUTE_NEAR_FAR_USING_PRIMITIVES;
+
+        osg::notify(osg::INFO)<<"Set compute near far mode to "<<_computeNearFar<<std::endl;
+        
+    }
+    
+    if ((ptr = getenv("OSG_NEAR_FAR_RATIO")) != 0)
+    {
+        _nearFarRatio = atof(ptr);
+
+        osg::notify(osg::INFO)<<"Set near/far ratio to "<<_nearFarRatio<<std::endl;
+    }
+    
+}
+
+void CullSettings::readCommandLine(ArgumentParser& arguments)
+{
+    // report the usage options.
+    if (arguments.getApplicationUsage())
+    {
+        arguments.getApplicationUsage()->addCommandLineOption("--COMPUTE_NEAR_FAR_MODE <mode>","DO_NOT_COMPUTE_NEAR_FAR | COMPUTE_NEAR_FAR_USING_BOUNDING_VOLUMES | COMPUTE_NEAR_FAR_USING_PRIMITIVES");
+        arguments.getApplicationUsage()->addCommandLineOption("--NEAR_FAR_RATIO <float>","Set the ratio between near and far planes - must greater than 0.0 but less than 1.0.");
+    }
+
+    std::string str;
+    while(arguments.read("--COMPUTE_NEAR_FAR_MODE",str))
+    {
+        if (str=="DO_NOT_COMPUTE_NEAR_FAR") _computeNearFar = DO_NOT_COMPUTE_NEAR_FAR;
+        else if (str=="COMPUTE_NEAR_FAR_USING_BOUNDING_VOLUMES") _computeNearFar = COMPUTE_NEAR_FAR_USING_BOUNDING_VOLUMES;
+        else if (str=="COMPUTE_NEAR_FAR_USING_PRIMITIVES") _computeNearFar = COMPUTE_NEAR_FAR_USING_PRIMITIVES;
+
+        osg::notify(osg::INFO)<<"Set compute near far mode to "<<_computeNearFar<<std::endl;
+    }
+
+    double value;
+    while(arguments.read("--NEAR_FAR_RATIO",value))
+    {
+        _nearFarRatio = value;
+
+        osg::notify(osg::INFO)<<"Set near/far ratio to "<<_nearFarRatio<<std::endl;
+    }
+
+}
diff --git a/src/osg/DisplaySettings.cpp b/src/osg/DisplaySettings.cpp
index d0ea1e894..2a5dbe806 100644
--- a/src/osg/DisplaySettings.cpp
+++ b/src/osg/DisplaySettings.cpp
@@ -28,7 +28,7 @@ DisplaySettings* DisplaySettings::instance()
 
 DisplaySettings::DisplaySettings(const DisplaySettings& vs):Referenced()
 {
-    copy(vs);
+    setDisplaySettings(vs);
 }
 
 DisplaySettings::~DisplaySettings()
@@ -39,11 +39,11 @@ DisplaySettings::~DisplaySettings()
  DisplaySettings& DisplaySettings::operator = (const DisplaySettings& vs)
 {
     if (this==&vs) return *this;
-    copy(vs);
+    setDisplaySettings(vs);
     return *this;
 }
 
-void DisplaySettings::copy(const DisplaySettings& vs)
+void DisplaySettings::setDisplaySettings(const DisplaySettings& vs)
 {
     _displayType = vs._displayType;
     _stereoMode = vs._stereoMode;