Frustum Culling is already available, and is a simple tick on a camera.
Currently there is no culling API’s and it is very a case specific.
There are many options that could work here, and many things could be implemented.
For outdoors some depth based occlusion to check if something os fully behind something else could work.
For indoors there are many techniques, one of them is sectors+portals, which actually you can do yourself by making 2 level graph of rooms (boundingbox of a room) and all entities within that room.
Then you have to make portals between sectors and know the state of a portal (open/close) and position, so that you know which connected rooms has to be visible or hidden.
Or toy might go another options which there is vast variety of.
So because there are many different occlusion techniques and they all are case specific, we haven’t implemented any particular. We might implement better interface that will help altering culling states of things, and allow to access culling state from scripts, so that you can prevent some costly logic if it is not needed when entity is not seen.