Skyboxes
Urho3D uses the model component Skybox to add backgrounds to a scene. It renders behind other models and moves with the camera to appear static.
To load a model as a Skybox:
skyNode=scene_->CreateChild("Sky");
Skybox* skybox=skyNode->CreateComponent<Skybox>();
skybox->SetModel(cache->GetResource<Model>("Models/Box.mdl"));
skybox->SetMaterial(cache->GetResource<Material>("Materials/Skybox.xml"));