diff --git a/MshViewer/Source/OpenGlController.cpp b/MshViewer/Source/OpenGlController.cpp
index d9b020a..384c0b8 100644
--- a/MshViewer/Source/OpenGlController.cpp
+++ b/MshViewer/Source/OpenGlController.cpp
@@ -326,52 +326,54 @@ void OpenGLController::updateScene()
 	// tell sampler to use texture unit 0
 	glUniform1i(gluiSamplerID, 0);
 
-	int instanceOffset(0);
-
-	for (unsigned int modelIndex = 0; modelIndex < vModels->size(); modelIndex++)
+	if (vModels != NULL)
 	{
-		// skip null, bones, shadowMesh, hidden things (don't increase textrue index!!)
-		if (vModels->at(modelIndex)->type == null ||
-			vModels->at(modelIndex)->type == bone ||
-			vModels->at(modelIndex)->type == shadowMesh ||
-			vModels->at(modelIndex)->renderFlags == 1)
-			continue;
+		int instanceOffset(0);
 
-		for (auto& segIt : vModels->at(modelIndex)->segmLst)
+		for (unsigned int modelIndex = 0; modelIndex < vModels->size(); modelIndex++)
 		{
-			// give texture to the shader
-			std::uint32_t tempTexIndex = segIt->textureIndex >= vTextures.size() ? vTextures.size() - 1 : segIt->textureIndex;
+			// skip null, bones, shadowMesh, hidden things (don't increase textrue index!!)
+			if (vModels->at(modelIndex)->type == null ||
+				vModels->at(modelIndex)->type == bone ||
+				vModels->at(modelIndex)->type == shadowMesh ||
+				vModels->at(modelIndex)->renderFlags == 1)
+				continue;
 
-			glTexImage2D(
-				GL_TEXTURE_2D,
-				0,
-				vTextures[tempTexIndex]->alpha ? GL_RGBA : GL_RGB,
-				vTextures[tempTexIndex]->width,
-				vTextures[tempTexIndex]->height,
-				0,
-				vTextures[tempTexIndex]->alpha ? GL_BGRA : GL_BGR,
-				GL_UNSIGNED_BYTE,
-				vTextures[tempTexIndex]->data->data()
-			);
+			for (auto& segIt : vModels->at(modelIndex)->segmLst)
+			{
+				// give texture to the shader
+				std::uint32_t tempTexIndex = segIt->textureIndex >= vTextures.size() ? vTextures.size() - 1 : segIt->textureIndex;
 
-			glGenerateMipmap(GL_TEXTURE_2D);
+				glTexImage2D(
+					GL_TEXTURE_2D,
+					0,
+					vTextures[tempTexIndex]->alpha ? GL_RGBA : GL_RGB,
+					vTextures[tempTexIndex]->width,
+					vTextures[tempTexIndex]->height,
+					0,
+					vTextures[tempTexIndex]->alpha ? GL_BGRA : GL_BGR,
+					GL_UNSIGNED_BYTE,
+					vTextures[tempTexIndex]->data->data()
+				);
 
-			// give the MVP to the shader
-			glUniformMatrix4fv(gluiMatrixID, 1, GL_FALSE, &getMVPMatrix(modelIndex)[0][0]);
+				glGenerateMipmap(GL_TEXTURE_2D);
 
-			// calculate the number of vertex
-			unsigned int vertexCount(0);
-			for (auto& it : segIt->meshIndices)
-				vertexCount += (it.size() - 2) * 3;
+				// give the MVP to the shader
+				glUniformMatrix4fv(gluiMatrixID, 1, GL_FALSE, &getMVPMatrix(modelIndex)[0][0]);
+
+				// calculate the number of vertex
+				unsigned int vertexCount(0);
+				for (auto& it : segIt->meshIndices)
+					vertexCount += (it.size() - 2) * 3;
 
 
-			glDrawArrays(GL_TRIANGLES, instanceOffset, vertexCount);
+				glDrawArrays(GL_TRIANGLES, instanceOffset, vertexCount);
 
-			// increase the offset
-			instanceOffset += vertexCount;
+				// increase the offset
+				instanceOffset += vertexCount;
+			}
 		}
 	}
-
 	glfwSwapBuffers(pWindow);
 	glfwPollEvents();
 }
diff --git a/MshViewer/main.cpp b/MshViewer/main.cpp
index 680742b..5cb889d 100644
--- a/MshViewer/main.cpp
+++ b/MshViewer/main.cpp
@@ -17,7 +17,9 @@ int main(int argc, char** argv)
 	else
 		scene = OpenGLController::getInstance();
 
+#ifdef _DEBUG
 	scene->loadMsh("..\\Release\\Msh\\quadPoly.msh");
+#endif // DEBUG
 
 	do {
 		scene->updateScene();