Mapping & Hammer

Hammer++ for GMod: Installation, Features and Differences

Hammer++ for Garry's Mod: what it does better than the bundled Hammer, how to install it, where its files live and which compilers it uses.

Published 8 October 20267 min read

Hammer++ is a free, heavily extended version of the Hammer Editor, developed by ficool2 and not by Valve. There is a dedicated build for Garry's Mod: it is copied into the game's bin/win64 folder as an addition and started through hammerplusplus.exe, while the bundled Hammer stays in place next to it. Hammer++ works with the same VMF files and calls GMod's own vbsp.exe, vvis.exe and vrad.exe to compile. The main additions are previews in the 3D view, brushes that are saved more precisely, better tools and a compile that no longer blocks the editor.

What Hammer++ is and who makes it

The project site describes Hammer++ as a free, extensive modification of Valve's Hammer. Its premise: be more stable and more up to date, fix many bugs and add features found in modern level editors. It is programmed by ficool2. The project is not affiliated with Valve.

Hammer++ comes in separate builds for different branches of the Source engine, among them Garry's Mod, Team Fortress 2 and Portal 2. According to the download page, the wrong build will not start. For GMod the page explicitly warns against the "Source SDK 2013 Multiplayer" build. The right entry is "Garry's Mod".

The basics of using the editor do not change. If you have never worked with Hammer, read Hammer Editor for Garry's Mod: setup and your first map first.

What changes in daily work

The features from the project's features page that stand out most in everyday building:

Area	What Hammer++ adds
Preview in the 3D view	Lighting preview ("camera" button in the 3D view, entry "3D Lighting Preview"), 2D skybox, 3D skybox (if it is an instance with a `sky_camera`), fog from `env_fog_controller`, particles, ropes and animated materials
Selecting and moving	Gizmo for moving, rotating and scaling directly in 3D, freely placed rotation point (Pivot, `Ctrl+P`), selecting by dragging while holding `Ctrl`
Brush tools	Clipping with three points (toggle with `C`), real-time Vertex Tool that marks invalid faces in red, Merge Tool (`Ctrl+Shift+M`), Polygon Tool
Accuracy	Vertices are saved exactly in the VMF and no longer drift from session to session
Browsers	Model browser with filters such as `debris 128` and exclusion with `!`, a new particle browser
Compile	Separate console window, Hammer++ does not freeze while compiling. Several cordons at once
Convenience	Hide editor objects (`Alt+O`), right click resets a keyvalue to its default, key bindings via Tools > Keybind Editor, open maps are saved after a crash

Installation for Garry's Mod

Check the folder. The GMod build of Hammer++ is a 64-bit program and belongs with the game's 64-bit files. See whether your installation contains the folder GarrysMod/bin/win64 with vbsp.exe, vvis.exe and vrad.exe. If it is missing, switch GMod to the x86-64 branch in Steam under Properties > Betas.
Download the right build. On the Hammer++ download page, choose "Garry's Mod".
Unpack as instructed. The installation steps are in the README.txt inside the download.
Check the result. Afterwards bin/win64 contains the file hammerplusplus.exe and the folder hammerplusplus. The download also includes the model viewer HLMV++, which is optional.
Start it. Open hammerplusplus.exe and create a shortcut for it.

GarrysMod/bin/hammer.exe                  bundled Hammer
GarrysMod/bin/win64/hammerplusplus.exe    Hammer++
GarrysMod/bin/win64/hammerplusplus/       settings, FGD, helper programs

In the installation examined for this article, Hammer++ had added hammerplusplus.exe, the hammerplusplus folder and the two HLMV++ files. No GMod file carried the date of that installation, and the bundled Hammer was still in place.

Where configuration and files live

Hammer++ does not share any settings with the bundled Hammer. Everything sits in the folder bin/win64/hammerplusplus:

File	Content
`hammerplusplus_gameconfig.txt`	Game configuration: game folder, FGD, compiler paths, target folder for BSPs
`hammerplusplus_settings.ini`	Options, colours and window positions
`hammerplusplus_sequences.cfg`	Compile sequences for the Expert mode of Run Map
`hammerplusplus_keybindings.cfg`	Key bindings
`hammerplusplus_fgd.fgd`	Mandatory file that Hammer++ loads by itself: preview helpers for existing entities and the entity `editor_text`
`bin/hammerplusplus_compiler.exe`	Starts the compile in its own window

After the first start, check Tools > Options. On the Game Configurations tab, "Game Data files" lists garrysmod.fgd from the bin folder, and the "Game Directory" points to garrysmod. On the Build Programs tab you find the three compilers and, under "Place compiled maps in this directory before running the game", the folder garrysmod/maps. Also make sure the file entered as "Game executable" really exists, otherwise the game will not start after the compile.

Compilers: the same tools, a different window

Hammer++ does not ship its own versions of VBSP, VVIS and VRAD. Its game configuration lists GMod's programs. In the installation examined, the bundled Hammer pointed to bin/vbsp.exe and Hammer++ to bin/win64/vbsp.exe, that is, to the 32-bit and the 64-bit version of the same tools.

How a BSP turns out therefore depends on the compiler and its parameters and not on the editor. Leaks, portals and lightmaps come about as before. What the three programs do is covered in VBSP, VVIS and VRAD explained.

What changes is the procedure. hammerplusplus_compiler.exe runs the steps in a console window, and the log is stored as a .log file next to the VMF as usual. For the Expert mode of Run Map, Hammer++ ships ready-made sequences:

Default                                 vbsp, vvis, vrad
Fast                                    vvis -fast, vrad -bounce 2 -noextra
LDR + HDR Full Compile                  vrad -both
LDR + HDR Full Compile -final (slow!)   vrad -both -final
Only Entities                           vbsp -onlyents

The lighting preview does not replace VRAD. It only simulates the light inside the editor. Your map's lightmaps are still calculated by VRAD, and only the compile shows the final result. More on that in the Source engine lighting guide. You can still paste messages from the log into the Map Scanner. It detects root causes, follow-up errors and matching fixes in VBSP, VVIS and VRAD logs.

Limitations and when the bundled Hammer is enough

File dialog freezes: On some Windows versions Hammer++ hangs in the Open dialog. The workaround from the download page: switch off FileDialogHack in hammerplusplus_settings.ini, that is, change 1 to 0.
No manifests: Hammer++ itself warns that manifests are not supported. Only instances are fully supported.
editor_text exists only in the editor: The entity displays 3D text in Hammer++ and, according to the project site, does not work in game.
Additional data in the VMF: Hammer++ saves the exact vertices in addition. It keeps writing the previous, less precise data so that compilers and other Hammer versions can read the file. In the options you switch this off with "Use precise vertex data".
Discord status: Hammer++ can show in Discord that you are working and on what. If you are building an unreleased map, switch this off in the options.

The bundled Hammer is enough when you are building your first rooms, or when you have no bin/win64 folder and do not want to switch branches. It also remains your fallback should Hammer++ ever fail to start.

FAQ

Does a map made in Hammer++ look different in game?

No. The BSP is produced by GMod's compilers, not by the editor. Previews for light, fog or particles only apply inside Hammer++. Differences in the result come from compile parameters such as -both or -final.

Does Hammer++ also show content from Counter-Strike: Source?

Most of it, and as far as the files show without mounting the game. Since the July 2025 update GMod has shipped most textures, models and sounds from CS:S itself, as the package content_cstrike in its sourceengine folder. gameinfo.txt does not list that package, but in the installation examined the program file hammerplusplus.exe contains its path, as do GMod's compilers. The quickest way to be sure is the texture browser: filter for de_dust, a folder from that package. Music, voice-over and the maps from CS:S are not included, and content from other games only appears when the game is mounted. According to the GMod wiki, folders entered in garrysmod/cfg/mount.cfg also apply to Hammer and the compilers. Whether your players will see the content later is covered in CS:S and HL2 content in GMod maps.

How do I update Hammer++?

Hammer++ can check for updates on startup and then offers to open the download in your browser. Copy the new files over your existing installation and confirm the overwrite. Replace all files when you do: Hammer++ compares the version of its FGD with that of the program and reports an outdated file.