Hammer

This article is about the official level editor for Half-Life 2 and other Source titles.

For the level editor for Half-Life and GoldSrc titles, see Valve Hammer Editor.

For Source 2 titles, see Hammer (Source 2).

Hammer 4.x splash screen.

Main view of Hammer 4.1.

Hammer 4.x is Valve's in-house level editor for Source titles, included in the Source SDK. It is a further evolution of Hammer 3.x. Many of its core concepts, features, and UI elements still match those of 3.x, as does the underlying mapping theory: building sealed levels with brushes and compiling them into BSP maps.

While in many ways improved, its core is still tied to ancient software architecture, and, being a product of its time, it often stuggles under the load of designing modern-looking levels.

Despite that, Half-Life 2 and every other Source title was built with it. Its relative ease of entry and gradual learning curve attract modders to this day.

Important:There are several community-made updates to Hammer (unfortunately, none are open-source, as the source code for Hammer has never been officially released, only either leaked, or available to licensees who kept it closed).
They are not essential for creating Source levels, but include bugfixes, QoL and extended features. They are listed further below.

Installing and launching

Older versions of Hammer are shipped in their respective Source SDK packages, and are intended to be launched via the Source SDK Launcher.

Since the Steampipe update, Hammer is installed automatically with the games, and is available in the /bin/ folder of a particular game (Half-Life 2/bin, Portal/bin, etc). However, in some cases, such as with Portal 2 and Left 4 Dead, their Authoring Tools need to be installed and launched to access Hammer.

Some of these sub-versions are interchangeable, such as between HL2, both of its Episodes, Portal, Counter-Strike: Source and Source 2013. Others, such as Portal 2's and Counter-Strike: Global Offensive, have certain exclusive features (Maya integration for P2, Sprinkle Tool for CS:GO) and may not be fully compatible with other titles.

For further information on setting up Hammer for Source, see Your First Map, Getting Started and its following articles.

See also Category:Hammer for more links to Hammer documentation.

Features and tools

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Compared to Hammer 3.x, the most notable new features include Displacements, I/O system, and using Source's own materialsystem for rendering textures and models. Later versions expanded on the user interface, adding the particle browser (since ASW), improved Model Browser, instances and other extra tools.

See also:  Category:Hammer Toolbars

Community fixes

• Slammin' Source Map Tools addresses performance and bug issues, adds convenience options and features, and comes with extended compilers: Slammin' Compile Tools;
• Hammer++ updates Hammer with additional tools and modernized workflow, realtime in-editor lighting preview, in-editor physics and more. It is based on the no longer available "SDK 2013 Hammer" project, which closed off access after its developers started working with an engine license;
• TeamSpen's Hammer Addons is a set of FGD enhancements, editor assets and scripts for working with Hammer, which don't directly modify the editor.

Developer resources

• Level Design Video Tutorials - a large collection of videos on mapping techniques and tricks across multiple Source titles.
• Mapping Sites and General Sites - listing of forums and resources in various languages.
• Map Archive Sites - for downloading existing maps (primarily for Half-Life 2).
• See Category:Level Design for all documentation on the subject.

Common issues

See also:  Compile Errors

No grid (black viewports)

First, check that the grid is on. The hotkey ⇧ Shift+R controls, so give it a try.

If that didn't help, check the formatting of your mod's gameinfo.txt.

It needs to include a key called SteamAppId, and the number after it needs to match the Steam Application ID of the base game you will be using to launch your mod.

This issue may also be caused by using a different Hammer version than the one intended for the game. To stay on the safe side, be sure to be launching hammer.exe from the /bin/ folder of the base game of your mod, or using Authoring Tools to launch it, if you're modding Portal 2, Left 4 Dead or Left 4 Dead 2 or Counter-Strike: Global Offensive.

Poor performance

The fault is inherent to Hammer's 32-bit and single-thread architecture. It will struggle to display too many detailed objects and draw levels across vast distances; this is even apparent with Half-Life 2's own stock levels. To make matters worse, having a large number of visible objects - regardless of what they are or how low-poly they are - will degrade both performance and input times, and make everything like selecting, editing settings, or moving objects take longer.

To fix it, keep the Model and Detail render distance in the 3D View tab of the Settings, on the lower side.

Tip:Hotkeys 1 and 2 move the 3D view clipping plane back and forth - you can use it to quickly adjust it and thus lessen the rendering load on the editor.

Make sure you didn't accidentally turn on Radius Culling by pressing C. This easy to press hotkey can cause huge performance loss and, to add insult to injury, make your level not compile until it is turned off.

The Radius Culling status is indicated by a circled red "R" on the Map Operations toolbar. Make sure it is de-pressed, unless you actually intend to use it.

Note:Depending on the Hammer version, the button and the feature itself may not be present altogether. Older - pre-Steampipe - Hammer didn't have it, while Slammin' Hammer and Hammer++ keep it off by default and remove the hotkey.

Version history

Version	Game/Branch	Release date	Features
4.0	All Source 2004 games	November 05, 2004	Initial release of Hammer in the Source SDK. Updates: Source Engine materials system. Materials created with the Source Engine's advanced shader-based texturing system are properly rendered inside the Hammer Editor. Displacement surfaces. A new class of mesh geometry that can be sculpted into different shapes and connected to one another to create terrain and other complex surfaces. Input and Outputs entity system. Entities use a new method to trigger and connect to one another, offering a higher level of flexibility and control than ever before. Hierarchical VisGroups. Objects can now be in multiple VisGroups, and Visgroups can be organized in a hierarchical manner for easier selection and organization. Entity Helpers. New user interface controls that make editing parameters on entities such as spotlights and doors easier and clearer. Per-face Lightmap controls. Lightmap density can be controlled on a per-face basis for more control over the balance of visual quality and rendering performance. Sound Browser. Built-in browser to hear a preview of sounds available to level designers. Non-modal Entity Report and Check for Problems dialogs. Dialogs are now non-modal, allowing for changes in the level and camera controls while using the information in the dialog boxes. Smoothing Groups. Per-face control of lighting-based smoothing. Find and Replace. Functions to both search and replace for text in any entity name, parameter, input, or output. Selection Mode toolbar. A new toolbar to control the impact of groups and entities upon the selection tools. Overlays. A new type of texture entity, similar to decals, but with far greater control over how it is applied to surfaces.
4.1	Half-Life 2: Lost Coast, All Source 2006 games and newer	November 22, 2005	Updates: HDR tools support. High Dynamic Range levels can be compiled and run from Hammer. VGUI Model Browser. All new model browser with a full tree control and real-time 3D previewing of model geometry, rendered with the Source material system. Enhanced 2D and 3D Views. 2D and 3D views are now rendered with a unified Source materials system, allowing for real-time feedback of transformations in all viewports simultaneously, and much faster rendering of the viewports. 2D model and displacement Rendering. Prop models and displacement geometry rendering in 2D viewports. Enhanced Auto Visgroups. A larger number of Visgroup categories, as well as an improved interface makes Visgroups more powerful. Autosave feature. Creates automatic, numbered backups of maps, with options for when and where backups are created. Paste Special enhancements. Provides options for renaming objects when pasted to avoid name collisions with automatic entity I/O fixup.
4.1	Source 2007	October 10, 2007	Updates: Inspecting Leaves in Hammer. You can now see visleaves using the Load Portal File option in Hammer, instead of using the glview application. Todo: Add more updates and changes in Source 2007 Hammer.
4.1 (unknown build)	Left 4 Dead	June 25, 2009	Initial release of Left 4 Dead Authoring Tools's Hammer.
4.1 (unknown build)	Left 4 Dead 2	Between November 17, 2009 and December 26, 2009	Initial release of Left 4 Dead 2 Authoring Tools's Hammer.  Question: When L4D2 tools was actually released?
4.1 (unknown launch build)	Alien Swarm	July 19, 2010	Valve Map Format (.vmf) that are created using this version are incompatible with previous version of Hammer without some modification and workarounds (such as using Left 4 Dead Authoring Tools/Left 4 Dead 2 Authoring Tools or editing VMF files). Updates: Added a way to export the selected brushes to Maya.
4.1 (unknown build)	Portal 2	May 6, 2011	Initial release of Portal 2 Authoring Tools's Hammer.[confirm]
4.1 (unknown build)	Portal 2	May 12, 2011	Fixes: Fixed certain keystrokes being ignored by Hammer when browsing models
4.1 (unknown build)	Portal 2	May 17, 2011	Fixes: Fixed crash that could occur when malformed brushes were saved in a map and then re-opened in Hammer. Hammer will now properly save maps after detecting and fixing malformed brushes. Fixes “Permission Denied” error some users were experiencing. Removed “Lighting Preview” option as this is not currently supported.
4.1 (unknown build)	Portal 2	May 20, 2011	Fixes: Fixed Hammer becoming unresponsive after launching map
4.1 (unknown build)	Portal 2	May 26, 2011 to May 21, 2012	Unknown
4.1 (BETA, unknown build)	Counter-Strike: Global Offensive	May 5, 2012 (or earlier)[confirm]	Initial release of Counter-Strike: Global Offensive Authoring Tools's Hammer.
4.1 (unknown launch build)	Counter-Strike: Global Offensive	August 21, 2012	Launch version of Counter-Strike: Global Offensive Authoring Tools's Hammer.
4.1 (build 8678)	Alien Swarm	September 24, 2020	Latest version for Alien Swarm.
4.1 (build 9008)	Source 2013	July 2, 2021	Latest version for Day of Defeat: Source, Half-Life 2: Deathmatch and Source SDK Base 2013 - Multiplayer
4.1 (build 9092)	Team Fortress 2	September 16, 2021	Unknown
4.1 (build 9109)	Team Fortress 2	October 5, 2021	Unknown
4.1 (build 9464)	Team Fortress 2	September 26, 2022	Unknown
4.1 (build 9520)	Half-Life 2	November 17, 2023	Latest version for Source 2013 (only in ).
4.1 (build 9540)	Team Fortress 2	December 8, 2022	Unknown
4.1 (build 10038)	Team Fortress 2	April 18, 2024	Added a dedicated 64 bit version.
4.1 (build 10042)	Team Fortress 2	April 22, 2024	Latest version for Team Fortress 2.