Using Mesh Level of Detail(LoD) within Ogre3d

For those who are not familiarized with the definition of LoD I might say that Level Of Details techniques is responsible for decreasing the complexity of a 3d object representation accordingly distance(the most usual way), camera position and/or eye-space speed.

Inside the graphical engine Ogre3d, the LoD is based on distance, actually the z distance from the mesh to the viewer camera, I'll write the code right down here, and then I'll explain each line. (Before using this method you have to generate a new and optimized
mesh file. Click here to see how you can use the optimize tool of 3dstudio max)

       MeshPtr mesh1 = MeshManager::getSingleton().load("animal.mesh",
              ResourceGroupManager::DEFAULT_RESOURCE_GROUP_NAME); 
       mesh1->createManualLodLevel(250, "animallod2.mesh");
       mesh1->createManualLodLevel(500, "animallod3.mesh");

       Entity* animal = mSceneMgr->createEntity("animalMeshWithLod", mesh1->getName() );
       SceneNode* node = mSceneMgr->getRootSceneNode()->createChildSceneNode();
       node->attachObject(animal);

In a first step we manually load a mesh file through the MeshManager and set it to a MeshPtr. The most important step: create the manualLodLevel through the method of the mesh class createManualLodLevel then we choose a depth value(the z distance that I told you before) and in a second parameter we tell which is the new mesh that ogre should show if the viewer camera reaches the z distance. Now we create an entity using this configured mesh file, and attach it to a SceneNode. compile it and you'll see the results. original size original size original size