Pull requests are welcome! Also, please submit an issue if you encounter a prolem, you can also contact me via email (see GitHub profile).
Sledge is an open-source alternative to Valve's Hammer Editor for the Goldsource and Source engines. It is written in .NET and uses OpenGL as a rendering platform.
Currently, Sledge supports Goldsource mapping in a limited capacity - features will be added during the alpha. A number of file format parsers are currently available, including FGD, RMF, VMF, MDL (limited support), and WAD (via HLLib).
While progress is slow, I have every intention of continuing work on this project. The current focus is on Goldsource support. After that, Source will be added, followed by a plugin system and more features.
The Sledge Editor is GPL. All other components are LGPL.