I think this particular idea of storing information in the BSP leaves was the big innovation brought to us by Id Software. Now, the elephant in the room is : ho

I think this particular idea of storing information in the BSP leaves was the big innovation brought to us by Id Software. Now, the elephant in the room is : how to build a well balanced BSP tree... But well, that's an entirely different question (I was a computer geometry researcher years ago... :-) )