diff --git a/src/kd_tree.cc b/src/kd_tree.cc
index fd3bc5d..ea5551d 100644
--- a/src/kd_tree.cc
+++ b/src/kd_tree.cc
@@ -25,15 +25,14 @@ ostream& operator<<(ostream &os, KdTree::Point const &point) {
     return os;
 }
 
+KdTree::Node::Node(Point const &position, vtkIdType id): position{position}, id{id} {}
+
 /////////////////////////////////////////////////////////////////////
 
 void KdTree::fill(std::vector<Tuple> &points) {
-    nodes.resize(points.size());
-
-    for(std::size_t i = 0; i < points.size(); ++i) {
-        nodes[i].position = points[i].first;
-        nodes[i].index = points[i].second;
-    }
+    nodes.reserve(points.size());
+    for(std::size_t i = 0; i < points.size(); ++i)
+        nodes.push_back({points[i].first, points[i].second});
 
     root = fillRec(0, points.size(), 0);
 }
diff --git a/src/kd_tree.h b/src/kd_tree.h
index e8232b1..4d35e30 100644
--- a/src/kd_tree.h
+++ b/src/kd_tree.h
@@ -30,8 +30,10 @@ public:
 
 private:
     struct Node {
+        Node(Point const &position, vtkIdType id);
+
         Point position;
-        vtkIdType index;
+        vtkIdType id;
 
         Node *leftChild;
         Node *rightChild;