Download ( Mac OS X 10.7, Mac OS X 10.8 ): -snip-
I was looking for the source code for one of my old projects when I found this. It works with Halo Demo/Halo Full on 10.8
Machines are fully supported (but you'll need to ask Sparky how to actually get them into swordedit...) BUT I have no idea whether this saves or not.
BSP Collisions do not save.