I create a simple hollow box in WED and compile a simple bsp map. When using ent_type(NULL) to display what kind of world it's generated, it reports the map created is a mesh based ABT map (ent_type return 2)... my question is how does the engine build a mesh based BSP map (where ent_type returned is 3)? Does it automatically select a mesh based BSP or ABT option depending on level geometry?