diff --git a/src/engine.cpp b/src/engine.cpp
index ca2acda..d62e1c9 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -11,8 +11,8 @@
 #include "scenetree.h"
 
 Engine::Engine() :
-    m_input(NULL),
     m_window(NULL),
+    m_input(NULL),
     m_world(NULL)
 {
     m_clock = new sf::Clock();
diff --git a/src/scenetree.cpp b/src/scenetree.cpp
index 809ff0d..f422506 100644
--- a/src/scenetree.cpp
+++ b/src/scenetree.cpp
@@ -24,14 +24,12 @@ void SceneTree::setMainCamera(CameraNode *camera)
 
 SceneIterator<Light*>* SceneTree::getLights()
 {
-    // TODO
-    return NULL;
+    return new ArrayIterator<Light*>(m_lights);
 }
 
 SceneIterator<GeometryNode*>* SceneTree::getGeometry()
 {
-    // TODO
-    return NULL;
+    return new ArrayIterator<GeometryNode*>(m_geometries);
 }
 
 void SceneTree::update()
@@ -39,6 +37,27 @@ void SceneTree::update()
     m_root.update();
 }
 
+void SceneTree::addObject(ContainerNode *parent, SceneNode *node)
+{
+    parent->addChild(node);
+    Light *light = node->getLight();
+    GeometryNode *geometrynode = node->getGeometryNode();
+    //TODO : Check for doublon in m_lights et m_geometries
+    if (light) m_lights.push_back(light);
+    if (geometrynode) m_geometries.push_back(geometrynode);
+}
+
+void SceneTree::removeObject(ContainerNode* parent,SceneNode *node){
+    parent->removeChild(node);
+    Light *l = node->getLight();
+    GeometryNode *g = node->getGeometryNode();
+    //TODO : remove light and geometrynode from m_lights et m_geometries
+    // debug following line
+//    m_lights.erase(std::remove(m_lights.begin(),m_lights.end(),&(*l)),m_lights.end());
+//    m_geometries.erase(std::remove(m_geometries.begin(),m_geometries.end(),g),m_geometries.end());
+}
+
+
 // Container Node
 
 void ContainerNode::update()
diff --git a/src/scenetree.h b/src/scenetree.h
index 60a52bc..821feb2 100644
--- a/src/scenetree.h
+++ b/src/scenetree.h
@@ -18,6 +18,8 @@ class SceneNode
 public:
     SceneNode* m_parent;
     virtual void update() = 0;
+    Light* getLight(){return nullptr;}
+    GeometryNode* getGeometryNode(){return nullptr;}
 };
 
 /**
@@ -64,16 +66,18 @@ public:
     void setSkybox(Texture* skybox) {m_skybox = skybox;}
 
     void setMainCamera(CameraNode *camera);
-    void addRootObject(SceneNode *node) {m_root.addChild(node);}
 
+    ContainerNode getRootObject(){return m_root;}
+    void addObject(ContainerNode *parent, SceneNode *node);
+    void removeObject(ContainerNode* parent,SceneNode *node);
 private:
     ContainerNode m_root;
+    std::vector<Light*> m_lights;
+    std::vector<GeometryNode*> m_geometries;
     Texture* m_skybox;
     SimplePipeline* m_simplepipeline;
 };
 
 // Additionnal Nodes :
 
-
-
 #endif // SCENETREE_H
diff --git a/src/sparrowshell.cpp b/src/sparrowshell.cpp
index 42d7602..30bfb5b 100644
--- a/src/sparrowshell.cpp
+++ b/src/sparrowshell.cpp
@@ -3,11 +3,11 @@
 #include "message.h"
 #include "input.h"
 
-const int SparrowShell::BUFFER_MAX_LENGTH = 50;
-const int SparrowShell::BUFFER_DISPLAYED_NUMBER = 10;
-const int SparrowShell::SCROLLBAR_PIXEL_WIDTH = 2;
+const unsigned int SparrowShell::BUFFER_MAX_LENGTH = 50;
+const unsigned int SparrowShell::BUFFER_DISPLAYED_NUMBER = 10;
+const unsigned int SparrowShell::SCROLLBAR_PIXEL_WIDTH = 2;
 
-SparrowShell::SparrowShell(sf::Window* window, Input* input): m_position(glm::ivec2(0,0)),m_window(window),m_input(input),m_scrollbar(this)
+SparrowShell::SparrowShell(sf::Window* window, Input* input): m_window(window),m_input(input),m_position(glm::ivec2(0,0)),m_scrollbar(this)
 {
     //m_dimension = glm::ivec2();//
 }
diff --git a/src/sparrowshell.h b/src/sparrowshell.h
index 1873631..ebe5892 100644
--- a/src/sparrowshell.h
+++ b/src/sparrowshell.h
@@ -28,9 +28,9 @@ private:
         void update();
     };
 
-    static const int BUFFER_MAX_LENGTH;
-    static const int BUFFER_DISPLAYED_NUMBER;
-    static const int SCROLLBAR_PIXEL_WIDTH;
+    static const unsigned int BUFFER_MAX_LENGTH;
+    static const unsigned int BUFFER_DISPLAYED_NUMBER;
+    static const unsigned int SCROLLBAR_PIXEL_WIDTH;
 
     std::list<std::string> m_buffer;
     sf::Window* m_window;