diff --git a/OpenSim/Region/Framework/Scenes/BinBVHAnimation.cs b/OpenSim/Region/Framework/Scenes/BinBVHAnimation.cs
index 367e8d83a3..1dd961333f 100644
--- a/OpenSim/Region/Framework/Scenes/BinBVHAnimation.cs
+++ b/OpenSim/Region/Framework/Scenes/BinBVHAnimation.cs
@@ -345,6 +345,12 @@ namespace OpenSim.Region.Framework.Scenes
             // argh! floats into two bytes!..   bad bad bad bad
             // After fighting with it for a while..  -1, to 1 seems to give the best results
             rotations = readKeys(data, ref i, rotationkeys, -1f, 1f);
+            for (int iter = 0; iter < rotations.Length; iter++)
+            {
+                rotations[iter].W = 1f -
+                    (rotations[iter].key_element.X + rotations[iter].key_element.Y +
+                     rotations[iter].key_element.Z);
+            }
 
 
             if (!BitConverter.IsLittleEndian)
@@ -481,6 +487,8 @@ namespace OpenSim.Region.Framework.Scenes
         /// </summary>
         public Vector3 key_element;
 
+        public float W;
+
         public void WriteBytesToStream(BinaryWriter iostream, float InPoint, float OutPoint, float min, float max)
         {
             iostream.Write(BinBVHUtil.ES(Utils.UInt16ToBytes(BinBVHUtil.FloatToUInt16(time, InPoint, OutPoint))));