--- a/src/netanim/examples/dumbbell-animation.cc	Wed Oct 19 07:00:15 2011 -0400
+++ b/src/netanim/examples/dumbbell-animation.cc	Wed Oct 19 14:25:39 2011 -0400
@@ -36,7 +36,7 @@
   uint32_t    nLeftLeaf = 5;
   uint32_t    nRightLeaf = 5;
   uint32_t    nLeaf = 0; // If non-zero, number of both left and right
-  std::string animFile;  // Name of file for animation output
+  std::string animFile = "dumbbell-animation.xml" ;  // Name of file for animation output
 
   CommandLine cmd;
   cmd.AddValue ("nLeftLeaf", "Number of left side leaf nodes", nLeftLeaf);
@@ -95,15 +95,8 @@
   d.BoundingBox (1, 1, 100, 100);
 
   // Create the animation object and configure for specified output
-  AnimationInterface anim;
-  if (!animFile.empty ())
-    {
-      anim.SetOutputFile (animFile);
-    }
-
-  anim.SetXMLOutput ();
-  anim.StartAnimation ();
-
+  AnimationInterface anim (animFile);
+  
   // Set up the acutal simulation
   Ipv4GlobalRoutingHelper::PopulateRoutingTables ();
 

--- a/src/netanim/examples/grid-animation.cc	Wed Oct 19 07:00:15 2011 -0400
+++ b/src/netanim/examples/grid-animation.cc	Wed Oct 19 14:25:39 2011 -0400
@@ -35,7 +35,7 @@
 
   uint32_t xSize = 5;
   uint32_t ySize = 5;
-  std::string animFile;
+  std::string animFile = "grid-animation.xml";
 
   CommandLine cmd;
   cmd.AddValue ("xSize", "Number of rows of nodes", xSize);
@@ -83,13 +83,7 @@
   grid.BoundingBox (1, 1, 100, 100);
 
   // Create the animation object and configure for specified output
-  AnimationInterface anim;
-  if (!animFile.empty ())
-    {
-      anim.SetOutputFile (animFile);
-    }
-  anim.SetXMLOutput ();
-  anim.StartAnimation ();
+  AnimationInterface anim (animFile);
 
   // Set up the actual simulation
   Ipv4GlobalRoutingHelper::PopulateRoutingTables ();

--- a/src/netanim/examples/star-animation.cc	Wed Oct 19 07:00:15 2011 -0400
+++ b/src/netanim/examples/star-animation.cc	Wed Oct 19 14:25:39 2011 -0400
@@ -55,7 +55,7 @@
   // Default number of nodes in the star.  Overridable by command line argument.
   //
   uint32_t nSpokes = 8;
-  std::string animFile;
+  std::string animFile = "star-animation.xml";
 
   CommandLine cmd;
   cmd.AddValue ("nSpokes", "Number of spoke nodes to place in the star", nSpokes);
@@ -115,13 +115,7 @@
   star.BoundingBox (1, 1, 100, 100);
 
   // Create the animation object and configure for specified output
-  AnimationInterface anim;
-  if (!animFile.empty ())
-    {
-      anim.SetOutputFile (animFile);
-    }
-  anim.SetXMLOutput ();
-  anim.StartAnimation ();
+  AnimationInterface anim (animFile);
 
   NS_LOG_INFO ("Run Simulation.");
   Simulator::Run ();

--- a/src/netanim/model/animation-interface.cc	Wed Oct 19 07:00:15 2011 -0400
+++ b/src/netanim/model/animation-interface.cc	Wed Oct 19 14:25:39 2011 -0400
@@ -32,6 +32,7 @@
 #include "ns3/animation-interface-helper.h"
 #include "ns3/wifi-mac-header.h"
 #include "ns3/wimax-mac-header.h"
+#include "ns3/constant-position-mobility-model.h"
 
 #include <stdio.h>
 #include <sstream>
@@ -58,6 +59,7 @@
     OutputFileSet (false), ServerPortSet (false), gAnimUid (0),randomPosition (true),
     m_writeCallback (0)
 {
+  StartAnimation ();
 }
 
 AnimationInterface::AnimationInterface (const std::string fn, bool usingXML)
@@ -66,6 +68,7 @@
     OutputFileSet (false), ServerPortSet (false), gAnimUid (0), randomPosition (true),
     m_writeCallback (0)
 {
+  StartAnimation ();
 }
 
 AnimationInterface::AnimationInterface (const uint16_t port, bool usingXML)
@@ -74,6 +77,7 @@
     OutputFileSet (false), ServerPortSet (false), gAnimUid (0), randomPosition (true),
     m_writeCallback (0)
 {
+  StartAnimation ();
 }
 
 AnimationInterface::~AnimationInterface ()
@@ -931,6 +935,21 @@
   WriteN (m_fHandle, oss.str ());
 }
 
+void AnimationInterface::SetConstantPosition (Ptr <Node> n, double x, double y, double z)
+{
+  NS_ASSERT (n);
+  Ptr<ConstantPositionMobilityModel> hubLoc =  n->GetObject<ConstantPositionMobilityModel> ();
+  if (hubLoc == 0)
+    {
+      hubLoc = CreateObject<ConstantPositionMobilityModel> ();
+      n->AggregateObject (hubLoc);
+    }
+  Vector hubVec (x, y, z);
+  hubLoc->SetPosition (hubVec);
+  NS_LOG_INFO ("Node:" << n->GetId () << " Position set to:(" << x << "," << y << "," << z << ")");
+
+}
+
 
 // XML Private Helpers
 

--- a/src/netanim/model/animation-interface.h	Wed Oct 19 07:00:15 2011 -0400
+++ b/src/netanim/model/animation-interface.h	Wed Oct 19 14:25:39 2011 -0400
@@ -193,6 +193,16 @@
    */
   void ResetAnimWriteCallback ();
 
+  /**
+   * \brief Helper function to set Constant Position for a given node
+   * \param n Ptr to the node
+   * \param x X co-ordinate of the node
+   * \param y Y co-ordinate of the node
+   * \param z Z co-ordinate of the node
+   *
+   */
+  void SetConstantPosition (Ptr <Node> n, double x, double y, double z=0);
+
 private:
 #ifndef WIN32
   int m_fHandle;  // File handle for output (-1 if none)