there is an API for frustum cull? i didn't find it.
i think in world.renderScene or world.draw , each Object3d is tested of frustum cull. if it's not in view , it's not sent to GPU.
in app, sometimes i need to test it too. for example if animation update of a group of Object3d is complex, i prefer to test frustum cull before updating animation.
if not in view, i just hide the objects.
for the non-hidden objects,
the test result is not communicated to the engine, so engine will test again.
if the world is rendered multiple times, frustum cull is tested multiple times. but in fact, it only need to be done once for a frame.
so it's better to turn of frustum cull in engine, in my case.