diff --git a/examples/osgkdtree/CMakeLists.txt b/examples/osgkdtree/CMakeLists.txt
index ff0b86fe6..d9f3ceaeb 100644
--- a/examples/osgkdtree/CMakeLists.txt
+++ b/examples/osgkdtree/CMakeLists.txt
@@ -1,10 +1,12 @@
 SET(TARGET_SRC 
     fixeddivision.cpp
+    variabledivision.cpp
     osgkdtree.cpp
 )
 
 SET(TARGET_H 
     fixeddivision.h
+    variabledivision.h
 )
 
 
diff --git a/examples/osgkdtree/osgkdtree.cpp b/examples/osgkdtree/osgkdtree.cpp
index e3b1fc979..50ce6efdd 100644
--- a/examples/osgkdtree/osgkdtree.cpp
+++ b/examples/osgkdtree/osgkdtree.cpp
@@ -38,6 +38,7 @@
 #include <osgSim/ElevationSlice>
 
 #include "fixeddivision.h"
+#include "variabledivision.h"
 
 
 int main(int argc, char **argv)
@@ -89,6 +90,22 @@ int main(int argc, char **argv)
     }
     else
     {
+        variabledivision::KDTreeBuilder builder;
+
+        builder._maxNumLevels = maxNumLevels;
+        builder._targetNumTrianglesPerLeaf = targetNumIndicesPerLeaf;
+        builder._processTriangles = processTriangles;
+
+
+        osg::Timer_t start = osg::Timer::instance()->tick();
+
+
+        scene->accept(builder);
+
+        osg::Timer_t end = osg::Timer::instance()->tick();
+        double time = osg::Timer::instance()->delta_s(start,end);
+        osg::notify(osg::NOTICE)<<"Time to build "<<time*1000.0<<"ms "<<builder._numVerticesProcessed<<std::endl;
+        osg::notify(osg::NOTICE)<<"build speed "<<(double(builder._numVerticesProcessed)/time)/1000000.0<<"M vertices per second"<<std::endl;
     }    
     
     return 0;
diff --git a/examples/osgkdtree/variabledivision.cpp b/examples/osgkdtree/variabledivision.cpp
new file mode 100644
index 000000000..ec3751d44
--- /dev/null
+++ b/examples/osgkdtree/variabledivision.cpp
@@ -0,0 +1,308 @@
+/* OpenSceneGraph example, osgintersection.
+*
+*  Permission is hereby granted, free of charge, to any person obtaining a copy
+*  of this software and associated documentation files (the "Software"), to deal
+*  in the Software without restriction, including without limitation the rights
+*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+*  copies of the Software, and to permit persons to whom the Software is
+*  furnished to do so, subject to the following conditions:
+*
+*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+*  THE SOFTWARE.
+*/
+
+
+#include "variabledivision.h"
+
+namespace variabledivision
+{
+
+struct TriangleIndicesCollector
+{
+    TriangleIndicesCollector():
+        _kdTree(0)
+    {
+    }
+
+    inline void operator () (unsigned int p1, unsigned int p2, unsigned int p3)
+    {
+        unsigned int i = _kdTree->_triangles.size();
+        _kdTree->_triangles.push_back(Triangle(p1,p2,p3));
+        
+        osg::BoundingBox bb;
+        bb.expandBy((*(_kdTree->_vertices))[p1]);
+        bb.expandBy((*(_kdTree->_vertices))[p2]);
+        bb.expandBy((*(_kdTree->_vertices))[p3]);
+        _kdTree->_boundingBoxes.push_back(bb);
+        
+        _kdTree->_centers.push_back(bb.center());
+
+        _kdTree->_primitiveIndices.push_back(i);
+        
+    }
+    
+    KDTree* _kdTree;
+
+};
+
+KDTree* KDTreeBuilder::createKDTree(osg::Geometry* geometry)
+{
+#ifdef VERBOSE_OUTPUT    
+    osg::notify(osg::NOTICE)<<"osg::KDTreeBuilder::createKDTree()"<<std::endl;
+#endif
+
+    osg::Vec3Array* vertices = dynamic_cast<osg::Vec3Array*>(geometry->getVertexArray());
+    if (!vertices) return 0;
+    
+    if (vertices->size() <= _targetNumTrianglesPerLeaf) return 0;
+
+    osg::ref_ptr<KDTree> kdTree = new KDTree;
+    kdTree->_geometry = geometry;
+    kdTree->_bb = kdTree->_geometry->getBound();
+    kdTree->_vertices = vertices;
+    
+    unsigned int estimatedSize = (unsigned int)(2.0*float(vertices->size())/float(_targetNumTrianglesPerLeaf));
+
+#ifdef VERBOSE_OUTPUT    
+    osg::notify(osg::NOTICE)<<"kdTree->_kdNodes.reserve()="<<estimatedSize<<std::endl<<std::endl;
+#endif
+
+    kdTree->_kdNodes.reserve(estimatedSize);
+    kdTree->_kdLeaves.reserve(estimatedSize);
+    
+    computeDivisions(*kdTree);
+
+
+    _numVerticesProcessed += vertices->size();
+
+    unsigned int estimatedNumTriangles = vertices->size()*2;
+    kdTree->_primitiveIndices.reserve(estimatedNumTriangles);
+    kdTree->_boundingBoxes.reserve(estimatedNumTriangles);
+    kdTree->_triangles.reserve(estimatedNumTriangles);
+    kdTree->_centers.reserve(estimatedNumTriangles);
+
+
+
+    osg::TriangleIndexFunctor<TriangleIndicesCollector> collectTriangleIndices;
+    collectTriangleIndices._kdTree = kdTree.get();
+    geometry->accept(collectTriangleIndices);
+
+    kdTree->_primitiveIndices.reserve(vertices->size());
+
+
+
+    KDLeaf leaf(0, kdTree->_primitiveIndices.size());
+
+    int leafNum = kdTree->addLeaf(leaf);
+
+    osg::BoundingBox bb = kdTree->_bb;
+    int nodeNum = divide(*kdTree, bb, leafNum, 0);
+
+#ifdef VERBOSE_OUTPUT    
+    osg::notify(osg::NOTICE)<<"Root nodeNum="<<nodeNum<<std::endl;
+#endif
+    
+    
+#ifdef VERBOSE_OUTPUT    
+    
+    KDTreeTraverser traverser;
+    traverser.traverse(*kdTree);
+    
+    
+    osg::notify(osg::NOTICE)<<"Final kdTree->_kdNodes.size()="<<kdTree->_kdNodes.size()<<std::endl;
+    osg::notify(osg::NOTICE)<<"Final kdTree->_kdLeaves.size()="<<kdTree->_kdLeaves.size()<<std::endl;
+
+    osg::notify(osg::NOTICE)<<"osg::KDTreeBuilder::createKDTree() completed"<<std::endl<<std::endl;
+#endif
+
+//    osg::notify(osg::NOTICE)<<"kdTree->_kdNodes.size()="<<kdTree->_kdNodes.size()<<"  estimated size = "<<estimatedSize<<std::endl;
+//    osg::notify(osg::NOTICE)<<"kdTree->_kdLeaves.size()="<<kdTree->_kdLeaves.size()<<"  estimated size = "<<estimatedSize<<std::endl<<std::endl;
+
+
+
+    return kdTree.release();
+}    
+
+void KDTreeBuilder::computeDivisions(KDTree& kdTree)
+{
+
+
+    osg::Vec3 dimensions(kdTree._bb.xMax()-kdTree._bb.xMin(),
+                         kdTree._bb.yMax()-kdTree._bb.yMin(),
+                         kdTree._bb.zMax()-kdTree._bb.zMin());
+
+#ifdef VERBOSE_OUTPUT    
+    osg::notify(osg::NOTICE)<<"computeDivisions("<<_maxNumLevels<<") "<<dimensions<< " { "<<std::endl;
+#endif
+
+    kdTree._axisStack.reserve(_maxNumLevels);
+ 
+    int level = 0;
+    for(unsigned int level=0; level<_maxNumLevels; ++level)
+    {
+        int axis = 0;
+        if (dimensions[0]>=dimensions[1])
+        {
+            if (dimensions[0]>=dimensions[2]) axis = 0;
+            else axis = 2;
+        }
+        else if (dimensions[1]>=dimensions[2]) axis = 1;
+        else axis = 2;
+
+        kdTree._axisStack.push_back(axis);
+        dimensions[axis] /= 2.0f;
+
+#ifdef VERBOSE_OUTPUT    
+        osg::notify(osg::NOTICE)<<"  "<<level<<", "<<dimensions<<", "<<axis<<std::endl;
+#endif
+    }
+
+#ifdef VERBOSE_OUTPUT    
+    osg::notify(osg::NOTICE)<<"}"<<std::endl;
+#endif
+}
+
+
+
+int KDTreeBuilder::divide(KDTree& kdTree, osg::BoundingBox& bb, int nodeIndex, unsigned int level)
+{
+    if (kdTree._axisStack.size()<=level) return nodeIndex;
+
+
+    int axis = kdTree._axisStack[level];
+
+#ifdef VERBOSE_OUTPUT    
+    //osg::notify(osg::NOTICE)<<"divide("<<nodeIndex<<", "<<level<< "), axis="<<axis<<std::endl;
+#endif
+
+    if (nodeIndex>=0)
+    {
+#ifdef VERBOSE_OUTPUT    
+        osg::notify(osg::NOTICE)<<"  divide node"<<std::endl;
+#endif
+        KDNode& node = kdTree.getNode(nodeIndex);
+        return nodeIndex;
+    }
+    else
+    {    
+
+        if (kdTree.getLeaf(nodeIndex).second<=_targetNumTrianglesPerLeaf) return nodeIndex;
+
+        //osg::notify(osg::NOTICE)<<"  divide leaf"<<std::endl;
+        
+        int nodeNum = kdTree.addNode(KDNode());
+
+        float original_min = bb._min[axis];
+        float original_max = bb._max[axis];
+
+        float mid = (original_min+original_max)*0.5f;
+
+        {
+            KDLeaf& leaf = kdTree.getLeaf(nodeIndex);
+
+            //osg::Vec3Array* vertices = kdTree._vertices.get();
+            KDTree::CenterList& centers = kdTree._centers;
+
+            int end = leaf.first+leaf.second-1;
+            int left = leaf.first;
+            int right = leaf.first+leaf.second-1;
+            
+            while(left<right)
+            {
+                while(left<right && (centers[kdTree._primitiveIndices[left]][axis]<=mid)) { ++left; }
+
+                while(left<right && (centers[kdTree._primitiveIndices[right]][axis]>mid)) { --right; }
+                
+                while(left<right && (centers[kdTree._primitiveIndices[right]][axis]>mid)) { --right; }
+
+                if (left<right)
+                {
+                    std::swap(kdTree._primitiveIndices[left], kdTree._primitiveIndices[right]);
+                    ++left;
+                    --right;
+                }
+            }
+            
+            if (left==right)
+            {
+                if (centers[kdTree._primitiveIndices[left]][axis]<=mid) ++left;
+                else --right;
+            }
+            
+            KDLeaf leftLeaf(leaf.first, (right-leaf.first)+1);
+            KDLeaf rightLeaf(left, (end-left)+1);
+
+#if 0            
+            osg::notify(osg::NOTICE)<<"In  leaf.first     ="<<leaf.first     <<" leaf.second     ="<<leaf.second<<std::endl;
+            osg::notify(osg::NOTICE)<<"    leftLeaf.first ="<<leftLeaf.first <<" leftLeaf.second ="<<leftLeaf.second<<std::endl;
+            osg::notify(osg::NOTICE)<<"    rightLeaf.first="<<rightLeaf.first<<" rightLeaf.second="<<rightLeaf.second<<std::endl;
+            osg::notify(osg::NOTICE)<<"    left="<<left<<" right="<<right<<std::endl;
+
+            if (leaf.second != (leftLeaf.second +rightLeaf.second))
+            {
+                osg::notify(osg::NOTICE)<<"*** Error in size, leaf.second="<<leaf.second
+                                        <<", leftLeaf.second="<<leftLeaf.second
+                                        <<", rightLeaf.second="<<rightLeaf.second<<std::endl;
+            }
+            else
+            {
+                osg::notify(osg::NOTICE)<<"Size OK, leaf.second="<<leaf.second
+                                        <<", leftLeaf.second="<<leftLeaf.second
+                                        <<", rightLeaf.second="<<rightLeaf.second<<std::endl;
+            }
+#endif
+            if (leftLeaf.second<=0)
+            {
+                //osg::notify(osg::NOTICE)<<"LeftLeaf empty"<<std::endl;
+                kdTree.getNode(nodeNum).first = 0;
+                kdTree.getNode(nodeNum).second = kdTree.replaceLeaf(nodeIndex, rightLeaf);
+            }
+            else if (rightLeaf.second<=0)
+            {
+                //osg::notify(osg::NOTICE)<<"RightLeaf empty"<<std::endl;
+                kdTree.getNode(nodeNum).first = kdTree.replaceLeaf(nodeIndex, leftLeaf);
+                kdTree.getNode(nodeNum).second = 0;
+            }
+            else
+            {
+                kdTree.getNode(nodeNum).first = kdTree.replaceLeaf(nodeIndex, leftLeaf);
+                kdTree.getNode(nodeNum).second = kdTree.addLeaf(rightLeaf);
+            }
+        }
+
+        
+        int originalLeftChildIndex = kdTree.getNode(nodeNum).first;
+        int originalRightChildIndex = kdTree.getNode(nodeNum).second;
+
+
+        float restore = bb._max[axis];
+        bb._max[axis] = mid;
+
+        //osg::notify(osg::NOTICE)<<"  divide leftLeaf "<<kdTree.getNode(nodeNum).first<<std::endl;
+        int leftChildIndex = divide(kdTree, bb, originalLeftChildIndex, level+1);
+
+        bb._max[axis] = restore;
+        
+        restore = bb._min[axis];
+        bb._min[axis] = mid;
+
+        //osg::notify(osg::NOTICE)<<"  divide rightLeaf "<<kdTree.getNode(nodeNum).second<<std::endl;
+        int rightChildIndex = divide(kdTree, bb, originalRightChildIndex, level+1);
+        
+        bb._min[axis] = restore;
+        
+        kdTree.getNode(nodeNum).first = leftChildIndex;
+        kdTree.getNode(nodeNum).second = rightChildIndex; 
+        
+        return nodeNum;        
+    }
+
+
+}
+
+}
diff --git a/examples/osgkdtree/variabledivision.h b/examples/osgkdtree/variabledivision.h
new file mode 100644
index 000000000..7a8573918
--- /dev/null
+++ b/examples/osgkdtree/variabledivision.h
@@ -0,0 +1,275 @@
+/* OpenSceneGraph example, osgintersection.
+*
+*  Permission is hereby granted, free of charge, to any person obtaining a copy
+*  of this software and associated documentation files (the "Software"), to deal
+*  in the Software without restriction, including without limitation the rights
+*  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+*  copies of the Software, and to permit persons to whom the Software is
+*  furnished to do so, subject to the following conditions:
+*
+*  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+*  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+*  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+*  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+*  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+*  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+*  THE SOFTWARE.
+*/
+
+#ifndef VARIABLEDIVISION_H
+#define VARIABLEDIVISION_H
+
+  
+#include <osgDB/ReadFile>
+
+#include <osg/ArgumentParser>
+#include <osg/ApplicationUsage>
+#include <osg/Timer>
+#include <osg/CoordinateSystemNode>
+#include <osg/Notify>
+#include <osg/io_utils>
+#include <osg/Geometry>
+#include <osg/TriangleIndexFunctor>
+
+
+#include <osgUtil/IntersectionVisitor>
+#include <osgUtil/LineSegmentIntersector>
+#include <osgUtil/UpdateVisitor>
+
+#include <osgSim/LineOfSight>
+#include <osgSim/HeightAboveTerrain>
+#include <osgSim/ElevationSlice>
+
+#include <iostream>
+
+
+namespace variabledivision
+{
+
+typedef int value_type;
+typedef std::vector< value_type >   Indices;
+
+//#define VERBOSE_OUTPUT
+
+typedef std::pair< value_type, value_type> KDNode;
+typedef std::pair< value_type, value_type> KDLeaf;
+
+struct Triangle
+{
+    Triangle(unsigned int p1, unsigned int p2, unsigned int p3):
+        _p1(p1), _p2(p2), _p3(p3) {}
+        
+    bool operator < (const Triangle& rhs) const
+    {
+        if (_p1<rhs._p1) return true;
+        if (_p1>rhs._p1) return false;
+        if (_p2<rhs._p2) return true;
+        if (_p2>rhs._p2) return false;
+        return _p3<rhs._p3;
+    }
+    
+    unsigned int _p1;
+    unsigned int _p2;
+    unsigned int _p3;    
+};
+
+class KDTree : public osg::Shape
+{
+    public:
+    
+    
+        KDTree() {}
+        
+        KDTree(const KDTree& rhs, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY):
+            Shape(rhs,copyop) {}
+
+        META_Shape(osg, KDTree)
+        
+    
+        typedef std::vector< unsigned int > AxisStack;
+        typedef std::vector< KDNode >       KDNodeList;
+
+        typedef std::vector< KDLeaf > KDLeafList;
+
+        /// note, leafNum is negative to distinguish from nodeNum
+        int addLeaf(const KDLeaf& leaf) { int num = _kdLeaves.size(); _kdLeaves.push_back(leaf); return -(num+1); }
+
+        int replaceLeaf(int leafNum, const KDLeaf& leaf)
+        {
+            int num = -leafNum-1; 
+            
+            if (num>_kdLeaves.size()-1)
+            {
+                osg::notify(osg::NOTICE)<<"Warning: replaceChild("<<leafNum<<", leaf), num = "<<num<<" _kdLeaves.size()="<<_kdLeaves.size()<<std::endl;
+                return leafNum;
+            }
+            
+            _kdLeaves[num] = leaf; return leafNum;
+        }
+
+        /// note, leafNum is negative to distinguish from nodeNum
+        KDLeaf& getLeaf(int leafNum)
+        {
+            int num = -leafNum-1;
+            if (num<0 || num>_kdLeaves.size()-1)
+            {
+                osg::notify(osg::NOTICE)<<"Warning: getLeaf("<<leafNum<<", num = "<<num<<") _kdLeaves.size()="<<_kdLeaves.size()<<std::endl;
+            }
+
+            return _kdLeaves[num];
+        }
+
+        int addNode(const KDNode& node)
+        {
+            int num = _kdNodes.size(); 
+            _kdNodes.push_back(node); 
+            return num;
+        }
+
+        /// note, nodeNum is positive to distinguish from leftNum
+        KDNode& getNode(int nodeNum)
+        {
+            if (nodeNum<0 || nodeNum>_kdNodes.size()-1)
+            {
+                osg::notify(osg::NOTICE)<<"Warning: getNode("<<nodeNum<<") _kdNodes.size()="<<_kdNodes.size()<<std::endl;
+            }
+            return _kdNodes[nodeNum];
+        }
+
+
+        typedef std::vector< osg::BoundingBox >                 BoundingBoxList;
+        typedef std::vector< Triangle >                         TriangleList;
+        typedef std::vector< osg::Vec3 >                        CenterList;
+
+        osg::observer_ptr<osg::Geometry>    _geometry;
+
+        osg::BoundingBox                    _bb;
+
+        AxisStack                           _axisStack;
+        KDNodeList                          _kdNodes;
+        KDLeafList                          _kdLeaves;
+
+        osg::ref_ptr<osg::Vec3Array>        _vertices;
+        
+        Indices                             _primitiveIndices;
+        
+        BoundingBoxList                     _boundingBoxes;
+        TriangleList                        _triangles;
+        CenterList                          _centers;
+};
+
+class KDTreeTraverser
+{
+    public:
+    
+    
+        std::ostream& output(unsigned int level)
+        {
+            for(unsigned int i=0; i<level; ++i)
+            {
+                osg::notify(osg::NOTICE)<<"  ";
+            }
+            return osg::notify(osg::NOTICE);
+        }
+    
+
+        void traverse(KDTree& tree, KDLeaf& leaf, unsigned int level)
+        {
+            output(level)<<"leaf("<<level<<") { ";
+
+            unsigned int end = leaf.first+leaf.second;
+            for(unsigned int i=leaf.first; i<end; ++i)
+            {
+                if (i==leaf.first) osg::notify(osg::NOTICE)<<tree._primitiveIndices[i];
+                else osg::notify(osg::NOTICE)<<", "<<tree._primitiveIndices[i];
+            }
+
+            osg::notify(osg::NOTICE)<<"}"<<std::endl;;
+            
+        }
+
+        void traverse(KDTree& tree, value_type nodeIndex, unsigned int level)
+        {
+            output(level)<<"traverse("<<nodeIndex<<", "<< level<<") { "<<std::endl;
+            
+            if (nodeIndex>=0)
+            {        
+                KDNode& node = tree._kdNodes[nodeIndex];
+                if (node.first) traverse(tree,node.first,level+1);
+                else output(level+1)<<"empty left child()"<<std::endl;
+                
+                if (node.second) traverse(tree,node.second,level+1);
+                else output(level+1)<<"empty right child()"<<std::endl;
+            }
+            else 
+            {
+                value_type leafIndex = -nodeIndex-1;
+                
+                KDLeaf& leaf = tree._kdLeaves[leafIndex];
+                traverse(tree, leaf, level);
+
+            }
+
+            output(level)<<"}"<<std::endl;;
+        }
+
+
+        void traverse(KDTree& tree)
+        {
+            osg::notify(osg::NOTICE)<<"traverse(tree)"<<std::endl;
+            if (!tree._kdNodes.empty()) 
+            {
+                traverse(tree,0,0);
+            }
+            else if (!tree._kdLeaves.empty())
+            {
+                traverse(tree, tree._kdLeaves.front(), 0);
+            }
+        }
+    
+};
+
+class KDTreeBuilder : public osg::NodeVisitor
+{
+    public:
+    
+        KDTreeBuilder():
+            osg::NodeVisitor(osg::NodeVisitor::TRAVERSE_ALL_CHILDREN),
+            _maxNumLevels(16),
+            _targetNumTrianglesPerLeaf(4),
+            _numVerticesProcessed(0),
+            _processTriangles(true)
+        {            
+        }
+    
+    
+        void apply(osg::Geode& geode)
+        {
+            for(unsigned int i=0; i<geode.getNumDrawables(); ++i)
+            {
+                osg::Geometry* geom = geode.getDrawable(i)->asGeometry();
+                if (geom)
+                {
+                    geom->setShape(createKDTree(geom));
+                }   
+            }
+        }
+    
+        KDTree* createKDTree(osg::Geometry* geometry);
+        
+        void computeDivisions(KDTree& kdTree);
+        
+        int divide(KDTree& kdTree, osg::BoundingBox& bb, int nodeIndex, unsigned int level);
+
+        unsigned int _maxNumLevels;
+        unsigned int _targetNumTrianglesPerLeaf;
+        
+        unsigned int _numVerticesProcessed;
+        bool         _processTriangles;
+        
+};
+
+
+}
+
+#endif