diff --git a/src/forwardmodule.cpp b/src/forwardmodule.cpp
index 686f754..c128339 100644
--- a/src/forwardmodule.cpp
+++ b/src/forwardmodule.cpp
@@ -86,26 +86,24 @@ void ForwardModule::lightPass(Camera* myCamera, Scene* scene, Light* light)
         for(SceneIterator<GeometryNode*>* geometryIt = scene->getGeometry();
             geometryIt->isValid(); geometryIt->next())
         {
-            // compute matrix attributes
             GeometryNode* node = geometryIt->getItem();
-            glm::mat4 modelViewMatrix = myCamera->getViewMatrix() * node->modelMatrix;
-            glm::mat4 mvp = myCamera->getProjectionMatrix() * modelViewMatrix;
-            glm::mat4 normalMatrix = glm::transpose(glm::inverse(modelViewMatrix));
-            if(light != NULL && light->isShadowCaster())
+            Material* mat = node->mesh->material;
+            if(mat->getFlags() == geometryFlagList[i]) // if flag matches material
             {
-                glm::mat4 lightMVP = Light::biasMatrix * light->getProjectionMatrix() * light->getViewMatrix() * node->modelMatrix;
-                shader->bindMat4(shader->getLocation("lightMVP"), lightMVP);
-            }
-            shader->bindMat4(shader->getLocation("viewMatrix"), myCamera->getViewMatrix());
-            shader->bindMat4(shader->getLocation("modelViewMatrix"), modelViewMatrix);
-            shader->bindMat3(shader->getLocation("normalMatrix"), glm::mat3(normalMatrix));
-            shader->bindMat4(shader->getLocation("MVP"), mvp);
-            // loop over material groups
-            for(int j=0; j<node->mesh->indiceGroups.size(); ++j)
-            {
-                Material* mat = node->getMesh()->indiceGroups[j].material;
-                if(mat->getFlags() == geometryFlagList[i])
-                    node->mesh->draw(shader);
+                // compute matrix attributes
+                glm::mat4 modelViewMatrix = myCamera->getViewMatrix() * node->modelMatrix;
+                glm::mat4 mvp = myCamera->getProjectionMatrix() * modelViewMatrix;
+                glm::mat4 normalMatrix = glm::transpose(glm::inverse(modelViewMatrix));
+                if(light != NULL && light->isShadowCaster())
+                {
+                    glm::mat4 lightMVP = Light::biasMatrix * light->getProjectionMatrix() * light->getViewMatrix() * node->modelMatrix;
+                    shader->bindMat4(shader->getLocation("lightMVP"), lightMVP);
+                }
+                shader->bindMat4(shader->getLocation("viewMatrix"), myCamera->getViewMatrix());
+                shader->bindMat4(shader->getLocation("modelViewMatrix"), modelViewMatrix);
+                shader->bindMat3(shader->getLocation("normalMatrix"), glm::mat3(normalMatrix));
+                shader->bindMat4(shader->getLocation("MVP"), mvp);
+                node->mesh->draw(shader);
             }
         }
     }
@@ -134,12 +132,11 @@ void ForwardModule::compileShaders(Scene* scene)
     for(int i=0; i<nb_geometry_flags; ++i)
         geometryFlags[i] = false;
 
-    for(SceneIterator<PhongEntity*>* entityIt = scene->getGeometry();
-        entityIt->isValid(); entityIt->next())
+    for(SceneIterator<GeometryNode*>* geometryIt = scene->getGeometry();
+        geometryIt->isValid(); geometryIt->next())
     {
-        Mesh* m = entityIt->getItem()->getMesh();
-        for(Mesh::Group &g : m->indiceGroups)
-            geometryFlags[g.material->getFlags()] = true;
+        Mesh* m = geometryIt->getItem()->mesh;
+        geometryFlags[m->material->getFlags()] = true;
     }
     for(int i=0; i<nb_geometry_flags; ++i)
     {
diff --git a/src/light.cpp b/src/light.cpp
index 9f40dd8..fcc19a5 100644
--- a/src/light.cpp
+++ b/src/light.cpp
@@ -102,31 +102,28 @@ void Light::generateShadowMap(Scene* scene)
     glAssert(glEnable(GL_DEPTH_TEST));
     glAssert(glDepthFunc(GL_LESS));
     glAssert(glCullFace(GL_FRONT));
-    for(SceneIterator<PhongEntity*>* entityIt = scene->getGeometry();
-        entityIt->isValid(); entityIt->next())
+    for(SceneIterator<GeometryNode*>* geometryIt = scene->getGeometry();
+        geometryIt->isValid(); geometryIt->next())
     {
         // compute matrix attributes
-        PhongEntity* entity = entityIt->getItem();
-        glm::mat4 lightMVP = getProjectionMatrix() * (getViewMatrix() * entity->modelMatrix);
+        GeometryNode* node = geometryIt->getItem();
+        glm::mat4 lightMVP = getProjectionMatrix() * (getViewMatrix() * node->modelMatrix);
         // loop over material groups
-        for(int j=0; j<entity->getMesh()->indiceGroups.size(); ++j)
+        Material* mat = node->mesh->material;
+        if(mat->getFlags() & ALPHA_MASK_FLAG)
         {
-            Material* mat = entity->getMesh()->indiceGroups[j].material;
-            if(mat->getFlags() & ALPHA_MASK_FLAG)
-            {
-                PhongMaterial* pmat = (PhongMaterial*)mat;
-                shaders[1]->bind();
-                pmat->alpha_mask->bind(ALPHA_MASK);
-                shaders[1]->bindMat4(shaders[1]->getLocation("MVP"), lightMVP);
-                shaders[1]->bindInteger(shaders[1]->getLocation("alphaMask"), ALPHA_MASK);
-                entity->drawGroup(j, false, true, false);
-            }
-            else
-            {
-                entity->drawGroup(j, false, false, false);
-                shaders[0]->bind();
-                shaders[0]->bindMat4(shaders[1]->getLocation("MVP"), lightMVP);
-            }
+            PhongMaterial* pmat = (PhongMaterial*)mat;
+            shaders[1]->bind();
+            pmat->alpha_mask->bind(ALPHA_MASK);
+            shaders[1]->bindMat4(shaders[1]->getLocation("MVP"), lightMVP);
+            shaders[1]->bindInteger(shaders[1]->getLocation("alphaMask"), ALPHA_MASK);
+            node->mesh->draw(shaders[1], false, true, false);
+        }
+        else
+        {
+            shaders[0]->bind();
+            shaders[0]->bindMat4(shaders[1]->getLocation("MVP"), lightMVP);
+            node->mesh->draw(shaders[0], false, false, false);
         }
     }
     glAssert(glCullFace(GL_BACK));
diff --git a/src/mesh.cpp b/src/mesh.cpp
index 20dd468..63f06ee 100644
--- a/src/mesh.cpp
+++ b/src/mesh.cpp
@@ -3,6 +3,9 @@
 #include <set>
 #include "glassert.h"
 #include "sparrowrenderer.h"
+#include "material.h"
+
+#define BUFFER_OFFSET(i) ((char *)NULL + (i))
 
 Mesh::Mesh() :
     material(NULL),
@@ -28,11 +31,11 @@ void Mesh::initGL(bool isDynamic)
     glAssert(glBindVertexArray(vao));
 
     nb_buffers = 2; // positions and indices buffers
-    if(mesh->hasNormals())
+    if(hasNormals())
         ++nb_buffers;
-    if(mesh->hasTexCoords())
+    if(hasTexCoords())
         ++nb_buffers;
-    if(mesh->hasTangents())
+    if(hasTangents())
         ++nb_buffers;
 
     // create VBOs
@@ -75,7 +78,7 @@ void Mesh::initGL(bool isDynamic)
 void Mesh::draw(Shader* shader, bool drawNormals, bool drawTexCoord, bool drawTangents)
 {
     bool crappy = (shader == NULL);
-    material.bindAttributes(shader);
+    material->bindAttributes(shader);
     glAssert(glBindVertexArray(vao));
     glAssert(glBindBuffer(GL_ARRAY_BUFFER, vbo[POSITION_BUFFER]));
     if(crappy)
@@ -154,7 +157,7 @@ struct VertexComparator
 {
     // c'est plutot crade mais j'ai pas trouve d'autre moyen pour le moment
     static Mesh* mesh;
-    static void setMesh(MeshBuilder* m) {VertexComparator::mesh = m;}
+    static void setMesh(Mesh* m) {VertexComparator::mesh = m;}
 
     bool operator() (const int& vertId1, const int& vertId2) const
     {
@@ -198,7 +201,7 @@ void Mesh::mergeVertices()
     {
         if(indices[i] >= positions.size())
             indices[i] = swapped[swappedOffset - indices[i]];
-        std::pair<std::set<int,VertexComparator>::iterator,bool> ret = vertexSet.insert(g.indices[i]);
+        std::pair<std::set<int,VertexComparator>::iterator,bool> ret = vertexSet.insert(indices[i]);
         if(!ret.second) // duplicate found
         {
             // updating indices references
diff --git a/src/mesh.h b/src/mesh.h
index 5e4b42e..8b9d2bf 100644
--- a/src/mesh.h
+++ b/src/mesh.h
@@ -13,6 +13,7 @@ struct Mesh
 {
 protected:
 
+public: // TODO : see if there is a way to set this protected
     // geometry data
 
     typedef struct
@@ -21,6 +22,7 @@ protected:
 		glm::vec3 binormal;
     } Tangents;
 
+
     Material* material;
 
     std::vector<glm::vec3> positions;
@@ -29,6 +31,8 @@ protected:
     std::vector<Tangents> tangents;
     std::vector<unsigned int> indices;
 
+protected:
+
     // opengl
 
     enum {