diff --git a/include/osgAnimation/RigTransformSoftware b/include/osgAnimation/RigTransformSoftware
index 9d2a014dc..fa8aabcb9 100644
--- a/include/osgAnimation/RigTransformSoftware
+++ b/include/osgAnimation/RigTransformSoftware
@@ -53,7 +53,6 @@ namespace osgAnimation
             osg::observer_ptr< Bone > _boneptr;
         };
         typedef std::vector<BonePtrWeight>  BonePtrWeightList;
-        typedef std::vector<unsigned int> IndexList;
 
         /// map a set of boneinfluence to a list of vertex indices sharing this set
         class VertexGroup
@@ -61,7 +60,7 @@ namespace osgAnimation
         public:
             inline BonePtrWeightList& getBoneWeights() { return _boneweights; }
 
-            inline IndexList& getVertexes() { return _vertexes; }
+            inline IndexList& getVertices() { return _vertexes; }
 
             inline void resetMatrix()
             {
@@ -122,9 +121,8 @@ namespace osgAnimation
             osg::Matrix _result;
         };
 
-
-
-        template <class V> void compute(const osg::Matrix& transform, const osg::Matrix& invTransform, const V* src, V* dst)
+        template <class V>
+        inline void compute(const osg::Matrix& transform, const osg::Matrix& invTransform, const V* src, V* dst)
         {
             // the result of matrix mult should be cached to be used for vertexes transform and normal transform and maybe other computation
             for(VertexGroupList::iterator itvg=_uniqInfluenceSet2VertIDList.begin(); itvg!=_uniqInfluenceSet2VertIDList.end(); ++itvg)
@@ -133,7 +131,7 @@ namespace osgAnimation
                 uniq.computeMatrixForVertexSet();
                 osg::Matrix matrix =  transform * uniq.getMatrix() * invTransform;
 
-                const IndexList& vertexes = uniq.getVertexes();
+                const IndexList& vertexes = uniq.getVertices();
                 for(IndexList::const_iterator vertIDit=vertexes.begin(); vertIDit!=vertexes.end(); ++vertIDit)
                 {
                     dst[*vertIDit] = src[*vertIDit] * matrix;
@@ -143,7 +141,8 @@ namespace osgAnimation
         }
 
 
-        template <class V> void computeNormal(const osg::Matrix& transform, const osg::Matrix& invTransform, const V* src, V* dst)
+        template <class V>
+        inline void computeNormal(const osg::Matrix& transform, const osg::Matrix& invTransform, const V* src, V* dst)
         {
             for(VertexGroupList::iterator itvg=_uniqInfluenceSet2VertIDList.begin(); itvg!=_uniqInfluenceSet2VertIDList.end(); ++itvg)
             {
@@ -151,7 +150,7 @@ namespace osgAnimation
                 uniq.computeMatrixForVertexSet();
                 osg::Matrix matrix =  transform * uniq.getMatrix() * invTransform;
 
-                const IndexList& vertexes = uniq.getVertexes();
+                const IndexList& vertexes = uniq.getVertices();
                 for(IndexList::const_iterator vertIDit=vertexes.begin(); vertIDit!=vertexes.end(); ++vertIDit)
                 {
                     dst[*vertIDit] = osg::Matrix::transform3x3(src[*vertIDit],matrix);
diff --git a/include/osgAnimation/VertexInfluence b/include/osgAnimation/VertexInfluence
index 1b35b2c0f..4bb42b105 100644
--- a/include/osgAnimation/VertexInfluence
+++ b/include/osgAnimation/VertexInfluence
@@ -46,14 +46,6 @@ namespace osgAnimation
     typedef std::vector<BoneWeight> BoneWeightList;
     typedef std::vector<unsigned int> IndexList;
 
-    /// map a set of boneinfluence to a list of vertex indices sharing this set
-    class VertexGroup: public std::pair<BoneWeightList, IndexList>
-    {
-    public:
-        inline const BoneWeightList& getBoneWeights()const { return first; }
-        inline void setBoneWeights(BoneWeightList&o) {  first=o; }
-        inline IndexList& vertIDs() { return second; }
-    };
     class OSGANIMATION_EXPORT BoneInfluenceList : public IndexWeightList
     {
     public:
@@ -82,9 +74,19 @@ namespace osgAnimation
         void cullInfluenceCountPerVertex(unsigned int maxnumbonepervertex, float minweight=0, bool renormalize=true);
 
         //compute PerVertexInfluenceList
-        void computePerVertexInfluenceList(std::vector<BoneWeightList>& vertex2Bones,unsigned int numvert)const;
-        //create the minimal VertexGroup set
-        void computeMinimalVertexGroupList(std::vector<VertexGroup>&uniqVertexGroupList,unsigned int numvert)const;
+        void computePerVertexInfluenceList(std::vector<BoneWeightList>& perVertexInfluenceList, unsigned int numvert)const;
+
+        /// map a set of boneinfluence to a list of vertex indices sharing this set
+        class VertexGroup: public std::pair<BoneWeightList, IndexList>
+        {
+        public:
+            inline const BoneWeightList& getBoneWeights()const { return first; }
+            inline void setBoneWeights( BoneWeightList& o ) {  first=o; }
+            inline IndexList& vertIDs() { return second; }
+        };
+
+        /// compute the minimal VertexGroup Set in which vertices shares the same influence set
+        void computeMinimalVertexGroupList(std::vector<VertexGroup>&uniqVertexGroupList, unsigned int numvert)const;
     };
 
 }
diff --git a/src/osgAnimation/RigTransformSoftware.cpp b/src/osgAnimation/RigTransformSoftware.cpp
index d7d1515df..ff241bc91 100644
--- a/src/osgAnimation/RigTransformSoftware.cpp
+++ b/src/osgAnimation/RigTransformSoftware.cpp
@@ -20,6 +20,7 @@
 #include <osgAnimation/RigGeometry>
 
 #include <algorithm>
+
 using namespace osgAnimation;
 
 RigTransformSoftware::RigTransformSoftware()
@@ -35,7 +36,6 @@ RigTransformSoftware::RigTransformSoftware(const RigTransformSoftware& rts,const
 
 }
 
-
 // sort by name and weight
 struct SortByNameAndWeight : public std::less<RigTransformSoftware::BonePtrWeight>
 {
@@ -104,7 +104,7 @@ void RigTransformSoftware::buildMinimumUpdateSet(const BoneMap&boneMap,const Rig
             const unsigned int &index = iw.getIndex();
             float weight = iw.getWeight();
 
-            _vertex2Bones[index].push_back(BonePtrWeight(inflist.getBoneName(), weight,bone));;
+            _vertex2Bones[index].push_back(BonePtrWeight(inflist.getBoneName(), weight,bone));
         }
     }
 
@@ -135,19 +135,25 @@ void RigTransformSoftware::buildMinimumUpdateSet(const BoneMap&boneMap,const Rig
     typedef std::map<BonePtrWeightList, VertexGroup, SortByBoneWeightList> UnifyBoneGroup;
     UnifyBoneGroup unifyBuffer;
     vertexID=0;
+    ;
     for (std::vector<BonePtrWeightList>::iterator it = _vertex2Bones.begin(); it != _vertex2Bones.end(); ++it,++vertexID)
     {
-        BonePtrWeightList& bones = *it;
+        BonePtrWeightList bones = *it;
         // sort the vector to have a consistent key
         std::sort(bones.begin(), bones.end(), SortByNameAndWeight() );
         // we use the vector<BoneWeight> as key to differentiate group
         UnifyBoneGroup::iterator result = unifyBuffer.find(bones);
-        if (result == unifyBuffer.end())
-            unifyBuffer[bones].getBoneWeights()=bones;
-        unifyBuffer[bones].getVertexes().push_back(vertexID);
+        if (result != unifyBuffer.end())
+            result->second.getVertices().push_back(vertexID);
+        else
+        {
+            VertexGroup& vg = unifyBuffer[bones];
+            vg.getBoneWeights() = bones;
+            vg.getVertices().push_back(vertexID);
+        }
     }
     _uniqInfluenceSet2VertIDList.reserve(unifyBuffer.size());
-    for (UnifyBoneGroup::iterator it = unifyBuffer.begin(); it != unifyBuffer.end(); ++it)
+    for (UnifyBoneGroup::const_iterator it = unifyBuffer.begin(); it != unifyBuffer.end(); ++it)
         _uniqInfluenceSet2VertIDList.push_back(it->second);
     OSG_DEBUG << "uniq groups " << _uniqInfluenceSet2VertIDList.size() << " for " << rig.getName() << std::endl;
 }