As far as I know it is not possible. It is too expensive. It needs some sort of level cutting data to work with and make the process cheaper. The point is that if you check a million entities in order to do something with them, just a little complexity in the process will kill the frame rate for sure. That is the main role of any engine anyway. The proffesional edition has the BSP tree and regions, but I doubt they could be efficiently applied to any level. On the contrary, the level must be designed with those tools in mind. If I am not wrong, the engines BSP tree is an octree.