The method isn't perfect yet since it has too much artifacts on it, the Image on the tutorial link was made using a filtered image.
there's one pack on /vr/ that was made from the original sized pcx to tga textures unfiltered.
There's a guy who's working on another one using Nvidia's Gameworks tool.
the neural doom project was also made using a Paid tool along with Gameworks, and as the guy stated on the thread, it isn't perfect, it still needs optimization and retouches.
But the work is impressive, i kinda wish to see how Chthon would look like.