Team Fortress 2 engine branch

The Team Fortress 2 branch Team Fortress 2 branch (sometimes referred to as Source 2013 Multiplayer v2, Source 2025 Multiplayer, or the TF2 branch for short) is a newer version of Source 2013 Multiplayer Source 2013 Multiplayer , developed from updates to Team Fortress 2 Team Fortress 2 (since late 2015 or late 2021). Half-Life 2: Deathmatch was also upgraded to this branch after the 20th Anniversary update. All remaining Source 2013 Multiplayer games (Counter-Strike: Source , Half-Life Deathmatch: Source , Day of Defeat: Source and Source SDK Base 2013 - Multiplayer SDK Base 2013 - MP ) were upgraded to this branch on 18 February 2025, and SDK for this branch was released on the same day, completely succeeding Source 2013 Multiplayer.

Team Fortress 2 branch also adds new features and improvements, including ones from Half-Life 2's 20th Anniversary Update (bicubic lightmaps), the Left 4 Dead engine branch (radial fog) and other features from later branches.

This branch, along with Source 2013 Singleplayer, is currently the latest Source engine branch available, and actively being maintained by Valve. It is also the latest branch that are derived from Orange Box, while Portal 2 engine branch became the latest post-Orange Box branch that are still being maintained by Valve, after the release of Counter-Strike 2 and end of support for CS:GO (which includes CS:GO engine branch).

Some Source mods and tools that are built on Source 2013 Multiplayer (sometimes known as Source 2013 Multiplayer Legacy) will not work on this branch, due to semi-incompatible Wikipedia icon ABI s. Nonetheless, the TF2 branch is still considered a sub-branch of Source 2013 Source 2013 , alongside Source 2013 Singleplayer Source 2013 Singleplayer and the supplanted Source 2013 Multiplayer Source 2013 Multiplayer .

Features

Added

New since the Source 2013 Multiplayer Source 2013 Multiplayer branch is:

Wikipedia icon 64-bit binaries (also in Counter-Strike: Global Offensive for Mac/Linux, Garry's Mod )

Allows the game to access more than 4GB RAM and have slightly better performance. Additionally, tools such as Hammer, map compilers (VBSP, VVIS, VRAD), etc. also have 64-bit binaries.

Note.pngNote:64-bit is not available on Mac.

Icon-Bug.pngBug:The 64-bit versions of some tools, such as StudioMDL, are broken.

VScript (also in Mapbase No More Room in Hell Left 4 Dead engine branch Portal 2 engine branch CS:GO engine branch )

A powerful new scripting system primarily using Squirrel Squirrel . First introduced in April 2024 with Team Fortress 2 update. Third-party games may have different VScript implementation.

WebM video playback (64-bit only) (also in Hunt Down the Freeman Garry's Mod Counter-Strike: Global Offensive Strata Source )

Used for game intros or cutscenes. WebM allows smaller file sizes without significant degradation in video quality. In the Team Fortress 2 engine branch, it is only used in 64-bit mode, as 32-bit still use Bink & plays Bink video.

Note.pngNote:Not used in games like Half-Life 2: Deathmatch, Counter-Strike: Source, Day of Defeat: Source and Half-Life Deathmatch: Source, which continues to use Bink, but only when launched with 32-bit executable. 64-bit versions of the game fails to play Valve intro because it uses WebM, and valve.webm isn't present in hl2\media folder.

Vulkan renderer (also in Half-Life 2 Portal Left 4 Dead 2 Portal 2 engine branch CS:GO engine branch Strata Source Xengine )

A low-overhead, cross-platform graphics API, successor to OpenGL.

First introduced in 2022 with the release of Steam Deck update for Half-Life 2 and Portal, and later added to Team Fortress 2 during the 64-bit update. As all Valve games running on Source 2013 Multiplayer branch upgraded to TF2 branch, those games (such as Counter-Strike: Source Counter-Strike: Source ) now support Vulkan. This is disabled by default (on Windows), but can be enabled in supported games by passing -vulkan into the game's launch options. Vulkan is enabled by default on Linux.

VGUI High Wikipedia icon DPI support (also in Half-Life 2 20th, Portal , Half-Life: Source )

VGUI elements are now properly scalable on higher resolutions such as 4K (3840x2160).

Steam Networking (also in Synergy )

Allows self-hosting using Steam Datagram Relay, meaning users can easily create joinable servers without port forwarding.

Icon-Important.pngImportant:Enabled by default. If you are currently working on mapping for games that have Steam Networking enabled, make sure sv_use_steam_networking is set to 0 (disabled), to prevent users from easily joining your server. Alternatively, uncheck "Use Steam Networking" (in Counter-Strike: Source Day of Defeat: Source Half-Life 2: Deathmatch Half-Life Deathmatch: Source ) or set Server Type to "LAN" or "Friends Only" (Team Fortress 2 only).

Wikipedia icon Bicubic lightmap filtering (also in Half-Life 2 20th, Half-Life: Source , Portal )

Introduced in Half-Life 2 20th Anniversary Update (2024), bicubic filtering is used on lightmaps when r_lightmap_bicubic is enabled, smoothing out aliasing caused by the lower resolution of lightmaps. It can be also enabled by setting the Shader detail to "Very High".

Radial fog (also in Half-Life 2 20th, Half-Life: Source , Portal , Mapbase , all games since Left 4 Dead engine branch )

Unlike planar-based fog, radial fog does not strengthen or weaken the apparent amount of fog in a particular spot when you rotate the camera. It is first introduced in Left 4 Dead engine branch.

You can either use radial fog or planar-based fog by changing env_fog_controller "Use Radial Fog (fogRadial)" KeyValues.

Texture streaming (also in CS:GO engine branch Titanfall branch )

Reduces system RAM and graphics card VRAM usage by streaming textures as needed instead of loading them all when loading the map.

Swaying trees (also in Garry's Mod , Mapbase , Xengine , all games since Left 4 Dead 2 )

Introduced in Team Fortress 2 's Jungle Inferno update. A material parameter that gives the effect of trees swaying in the wind.

Updated shader compilation tools

Now by default SCell555's shader compiler is included in the SDK.

Changed / Fixes

VPhysics optimization

All games on Team Fortress 2 now ships with more optimized VPhysics (featured in Left 4 Dead engine branch to CS:GO engine branch), which was meant to improve performance on console and lower end hardware aswell to reduce network prediction errors and servers CPU usage for multiplayer. However this leads to unreliable collision detection due to reduced physics precision.^[2] This means in some cases props and other physics objects will briefly glitch through map object, other props or other physics objects.^[2]

Removed options to disable/enable Direct3D 9Ex (Windows Aero DirectX extensions) in Advanced Video Options.

While the option has been removed, likely because it does nothing when trying to disable it through in-game options/settings (possibly broken since Windows 10), disabling D3D9Ex through -nod3d9ex still works.

Numerous security fixes

See GitHub post.

Changes to game executable

Games running on this branch now have their own executable name (e.g. cstrike.exe and cstrike_win64.exe for Counter-Strike: Source, tf.exe and tf_win64.exe for Team Fortress 2) instead of hl2.exe.

Fixed building cubemaps

Building cubemaps on this branch no longer requires deleting pre-built (blank) cubemap, and building cubemaps doesn't need cheats to be enabled. However, you still needs to follow some of the steps correctly to make sure you built cubemaps on both LDR & HDR rendering and having consistent exposure/brightness on HDR cubemaps.

Removed

Miles Sound System middleware

Uses open-source minimp3 minimp3 for MP3 playback instead. Files related to Miles Sound System will remain on the game's 🖿bin folder (contains 32-bit DLLs), but left unused.

macOS macOS (OS X) support

Support for Mac was deprecated with Team Fortress 2 update back in 2024 (and applies to all other Source games), due to macOS previously dropping support for 32-bit applications back in 2019 with the release of macOS Catalina, and Valve does not plan to release native 64-bit Mac port.

Known issues / Report bugs

To report bugs or find existing issues on this engine branch, see Source games and Source SDK 2013 repo GitHub issues page in order to prevent duplicate or outdated bug reports at the wiki.

Availability and usage

Source code (game, tools) for this branch is available on GitHub. Full source code (such as Hammer and the rest of Source engine), are not publicly available, but it was leaked publicly in 2020.

To launch tools for these games, go to 🖿bin folder (for 32-bit binaries), or 🖿bin\x64 folder (for 64-bit binaries), then launch the following .bat files:

• hammer.bat - Hammer
• faceposer.bat - Faceposer
• hlmv.bat - Half-Life Model Viewer
• studiomdl.exe - StudioMDL
• vtex.bat - VTEX

Valve

• 2004 Counter-Strike: Source Counter-Strike: Source (formerly Source 2013 Multiplayer , Source Multiplayer *, Source 2009 *, Source 2006 , Source 2004 )
• 2004 Half-Life 2: Deathmatch Half-Life 2: Deathmatch (formerly Source 2013 Multiplayer , Source Multiplayer *, Source 2009 *, Source 2006 , Source 2004 )
• 2005 Day of Defeat: Source Day of Defeat: Source (formerly Source 2013 Multiplayer , Source Multiplayer *, Source 2009 *, Source 2007 , Source 2006 , Source 2004 )
• 2006 Half-Life Deathmatch: Source Half-Life Deathmatch: Source (formerly Source 2013 Multiplayer , Source 2006 )
• 2007 Team Fortress 2 Team Fortress 2 (formerly Source 2013 Multiplayer , Source Multiplayer *, Source 2009 *, Source 2007 )
• 2013 Source SDK Base 2013 - Multiplayer Source SDK Base 2013 - Multiplayer (formerly Source 2013 Multiplayer ; Click to Install)

Note.pngNote:Mods built on Source SDK Base 2013 - Multiplayer prior to the upgrade to the Team Fortress 2 branch may not work properly if the mod is launched with updated SDK Base 2013 MP, so if you want to use legacy version of Source SDK Base 2013 - Multiplayer to play older mods (or use older tools), follow the instructions:

1. Open Steam, go to Source SDK 2013 Multiplayer, right click Properties
2. A window will open. Go to "Betas", select previous2021 beta branch.
3. Steam will automatically re-download the files. Once it's done, run Source SDK Base 2013 MP as normal, or use it's tools.

Third-Party

• 2009 NEOTOKYO° NEOTOKYO° (as Neotokyo; Rebuild, currently in alpha, currently Source 2006 )
• 2014 Team Fortress 2 Classic Team Fortress 2 Classic - Steam version, coming soon (currently Source 2013 Multiplayer with Mapbase)
• 2019 Pre-Fortress 2 Pre-Fortress 2 - Steam version, coming soon (currently Source 2013 Multiplayer )
• 2019 Open Fortress Open Fortress - Steam version, coming soon (currently Source 2013 Multiplayer )
• 2024 Team Fortress 2: Gold Rush Team Fortress 2: Gold Rush

System Requirements (SDK)

These system requirements applies to Source SDK 2013 Multiplayer (2025), and some Team Fortress 2 branch based game only. Some other games may have their own system requirements.

References

• Team Fortress 2
• Source
• Pages with uncategorized bugs
• Engine branches
• Source engine branches
• First-party engine branches

• Translation
• English