smgr->getSceneNodesFromType(scene::ESNT_UNKNOWN, nodes); // Find all nodes

void registerCollision(irr::scene::ISceneNode* node, irr::scene::IMetaTriangleSelector * meta, irr::scene::ISceneManager* smgr)
{
    irr::scene::ITriangleSelector * selector = 0;
   
   switch(node->getType())
   {
      case irr::scene::ESNT_CUBE:
         printf("cube");
         break;
      
       case irr::scene::ESNT_ANIMATED_MESH:
         // Because the selector won't animate with the mesh,
         // and is only being used for camera collision, we'll just use an approximate
         // bounding box instead of ((scene::IAnimatedMeshSceneNode*)node)->getMesh(0)
         selector = smgr->createTriangleSelectorFromBoundingBox(node);
         printf("Anim. MEsh");
         break;
         
      case irr::scene::ESNT_MESH:
      case irr::scene::ESNT_SPHERE: // Derived from IMeshSceneNode
         selector = smgr->createTriangleSelector(((irr::scene::IMeshSceneNode*)node)->getMesh(), node);
         printf("MEsh");
         break;
      
      case irr::scene::ESNT_TERRAIN:
         selector = smgr->createTerrainTriangleSelector((irr::scene::ITerrainSceneNode*)node);
         printf("Terrain");
         break;
      
      case irr::scene::ESNT_OCT_TREE:
         selector = smgr->createOctTreeTriangleSelector(((irr::scene::IMeshSceneNode*)node)->getMesh(), node);
         printf("octree");
         break;
      
      default:
         // Don't create a selector for this node type
         printf("defaul");
         break;
   }
   if(selector)
   {
      // Add it to the meta selector, which will take a reference to it
      meta->addTriangleSelector(selector);
      // And drop my reference to it, so that the meta selector owns it.
      selector->drop();
   }
   irr::core::list<irr::scene::ISceneNode*>::ConstIterator it = node->getChildren().begin();
   while (it != node->getChildren().end())
   {
      registerCollision(*it, meta, smgr);
      ++it;
   }
}

registerCollision(smgr->getRootSceneNode(), meta, smgr);