How to reduce a large scene cost

I have a large scene and there are a lot of models in this scene!Most of them are out of the camera,and i dont want the graphics to draw them.but when they come into the camera,they will be draw automaticly.
I dont want to iterate all the models and caculate the distance.can this engine do this automaticly.

To my understanding only by reading the code ,you don’t have to take care for it .
Adding Octree component to your scene will do exactly that .
i.e. “scene_->CreateComponent();”
You don’t have to do anything

Some reference in the code :
It’s done each frame.

See file “/Urho3D-master/Source/Urho3D/Graphics/View.cpp” :
See Functions:
“void View::GetDrawables()”
“void CheckVisibilityWork(const WorkItem* item, unsigned threadIndex)”

Eventually each drawable will contain a list of cameras from which it will be visible from (or not) .
See file : “/Urho3D-master/Source/Urho3D/Graphics/Drawable.cpp”
See Function : “bool Drawable::IsInView(Camera* camera) const”