NetRadiant
NetRadiant is a map editor for the id tech 3 or id tech 4 engines. It is a fork of GtkRadiant, and has more features added for newer games such as Xonotic and Warsow. It comes with the Q3Map2 BSP compiler.
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/da/NetRadiant-start.png/220px-NetRadiant-start.png)
Although this book has been written using Xonotic as an example, other games should be similar.