Microbrush 2 is the successor to Microbrush, this time with actual usability features such as a menu system included! Edit tens of thousands of brushes, associate information with them, and then squeeze it all through converters to get levels for your favorite games! Customize your MB2 - you can change virtually everything in the config this time, not just the key bindings and colors! Basic converter source codes are to be shipped too, so you can easily use the output for your own hobby projects. There's a properly specified XML exchange format for you to depend on: Store your levels in that format in plaintext, and you'll be prepared to adapt for whatever incompatibilities might come up in the future! I don't know why, but a few people claim that this one is actually more intuitive than Hammer :D

A brush editor with features from Radiant and others to enhance the mapping workflow for Valve's Hammer for Source Engine games.

Imperator is a parser generator for LL(*) context free grammars. It supports regular expressions for tokens, syntactic lookahead within lookahead, and generates actually readable (debug-able) code. The grammar definitions are easy to create and maintain, and deployment of a generated parser is trivial. The output exploits features of modern target languages, like nodes in the output tree being typed as inner and leaf nodes. Leaf nodes (tokens) not only have images of their matched content, they also contain

Accuracy 2, the generative modeling language.

A command-line utility for conversion of maps in Valve's Map Format (VMF) to the binary format of Microbrush, for importing architecture from Valve's Hammer.
C# sources included. Licensed under the GPL v. 3.

A command-line utility for quick conversion of common image file formats to the JPG format (of specified quality).
C# sources included. Licensed under the GPL v. 3.

A command-line utility for quick conversion of common image file formats to Accuracy 2 input data.
C# sources included. Licensed under the GPL v. 3.