Doom Tools

These are the tools I use to create mods for Doom. There are others out there, but the general consensus is that these are among the best. These modern tools are a lot better than what was available in the past- they are more capable and far, far easier to use.

GZDoom Builder

GZDoom Builder is a fork of Doom Builder 2, and unlike the latter is still actively developed. It fully supports the UDMF map format and all GZDoom editing features. The interface is simple and not intimidating, but the editor is still very powerful. One of its best features is a 3D mode which allows you to preview maps without launching the game and make changes in real time.

To the best of my knowledge, GZDoom Builder is exclusive to Windows. The latest numbered version is 2.23, but the latest SVN build is recommended. It is open-source, with the code available from a SVN repository.

SLADE3

SLADE3 is an all-in-one Doom editor, used primarily for archive and resource editing. It can work with classic WAD archives, pk3 archives, raw folders, and even other games' archive formats. It supports viewing, editing, and conversion of a wide variety of standard and non-standard resource formats. It also provides a code editor and can even auto-generate some definition lumps. SLADE3 also includes a map editor, but I haven't used it and can't speak to its quality.

SLADE3 is available for Windows and Mac. Linux users may be able to use the DRD Team repository but will otherwise have to build from source. The current version is 3.1.1.1, and no newer beta build is available. It is open-source with its own Git repository.