(February 23, 2018)
TrenchBroom is a level editor for Quake, Quake II and Hexen II (support for more games planned in the future) with the unique feature of being able to build and edit levels entirely in 3D, without the use of grids or 2D viewports. TrenchBroom is founded on the idea that 2D viewports restrict the level designer, making them think in 2D rather than in 3D. Any and all level design functions, including, making, clipping, and vertex manipulating brushes, can be done in 3D, making the formerly preview-only window your entire workspace. (Though up to three 2D viewports are provided, they're disabled by default.)
TrenchBroom's editing tools are built for creating varied and complex geometry easily. You can set up to three clip points with the clipping tool, and invalid solids are automatically triangulated (split into smaller, triangular brushes). Face, edge, and vertex selection tools, as well as different CSG tools for merging and subtracting brushes, are provided to make it easy to create exactly the shapes desired.
TrenchBroom also features a unique drag-and-drop entity browser for placing entities into the world. Entity keyvalues and spawnflags are extendable using FGD (Worldcraft) and DEF (Radiant) definition files. Extensive documentation is available with the program.
TrenchBroom is built to be a modern, portable level editor; as such, binaries are available for Windows, MacOS, and Linux in both Red Hat and Debian package formats. (Windows users will also need to grab the x86 Visual C++ Redistributable 2015 libraries.) Full source code is also available on Kristian's GitHub.