qvoidwad
3D to GZDoom void map converter
This utility converts raw maps built for true 3D games such as Half-Life, Quake etc. into 2.5D levels for GZDoom, a port of Doom.
It converts the 'brushes' from 3D games to '3D floors' from modified 2.5D games (like GZDoom).
Since it is a command-line tool, it should compile and work with any operating system that supports the standard C and C++ libraries.