"Actor enters 3d floor" triggers

[printz]

I wonder if there could be Things that cause a special to activate when the player touches, enters or exits a passable [possibly invisible] 3d floor, similar to the already existing things that do the same with sectors, and similar to the triggers in Quake. This would prove useful to make specials that activate only when the player interacts with a specific box in the XYZ space. There are already triggers for passing through Boom fake planes for example.