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Garry's Mod ▶ 
S&box
Watch this page, Steam News, or Steam Updates for more information.
Supported OS: 
Windows (See system requirements)
Also available from the following other storefronts or websites:
Get S&box open beta
Notice: Currently in development, available as a open developer preview.
S&box is a platform and game development toolkit developed by Facepunch studio powered by a highly modified version of Source 2, planned to be a spiritual successor to Garry's Mod. Initially, the development was based on 
Unreal Engine 4, but as soon as Half-Life: Alyx came out, Facepunch immediately requested the engine branch of the newly-published game. A few weeks later Valve gave Facepunch access to the terabyte large repository, after which, in 2020, S&box's transition to Source 2 was announced. This is the first (and currently only) time that Source 2 has been licensed to third-party developers.
Note:S&box is not just a modding game! It is a complete package including a modified and fully featured Source 2 engine toolkit with C# bindings, and a distribution platform named s&box Game.
Contents
- 1 User Access
- 2 Features
- 3 UGC Content Distribution
- 4 Scene System
- 5 Maps
- 5.1 Project control panel
- 5.2 Publication
- 5.3 Characteristics
- 6 Programming
- 7 Shaders
- 8 External links
- 8.1 For Developers
- 8.2 Other
User Access
S&box is currently in open developer preview.
Access is available from the S&box site here. Users must sign in through Steam on website to claim access to the preview.
Features
S&box runs on highly modified version of Source 2 with the following features:
- Box3D physics engine
- A modified version of Rubikon physics engine without Valve specific code that can be quickly updated. Originally referred to as Izabu
UGC Content Distribution
Instead of using the Steam Workshop for storing UGC Content S&box uses a custom web based backend called s&box Game.
Scene System
S&box does away with the legacy Entity System and utilizes a Scene System which lets you have a Scene that is a collection of Game Objects to make up the game world. closely resembling the way things are done in Unity
Maps
Hammer Dated July 26th 2022
Mappers are provided with a modified version of the Source 2 Hammer map editor, with some parts exposed for C# scripting for increased flexibility.
Project control panel
In the projects menu in the dev tools, you can restrict map selection for your game mode. You can limit it to specific curated maps or maps tagged with supporting the game mode.
Publication
Currently, maps can be included with a game mode or released as a separate project(one for each map). The map is published by clicking on a special button in the projects menu in the developer toolkit.
Characteristics
| Available territory | Unlimited for models, but 32768 units (624.23 m / 2048 ft) for meshes |
| Visibility | Unlimited. The player currently sees approximately 78740 units (2 km / 6561,68 ft) in front of him by default, but values can be increased using C# |
Warning:Lighting baking beyond 32768 units is temporarily unavailable.
Warning:The nav mesh has not yet been adapted for large spaces, which will cause your OS to freeze if the size of the available territory exceeds 32768 units. In the event of a freeze, the only way out will be an emergency shutdown of the computer. Turn off the navigation mesh in the map compilation window!
Warning:There are problems with Floating point precision. Polygons start behaving incorrectly if you are too far from the zero coordinates (faint defects start after crossing 8 km, and are extremely noticeable after 20 km)
Programming
ActionGraph Example
S&box user content is programmed with C#, Microsoft's managed, object-oriented programming language of .NET fame. S&box includes an API which provides bindings to the underlying Source 2 engine and to Facepunch's middleware. All code in user content is distributed in source form, which S&box later compiles on-demand with Roslyn. Language support is stated to permit C# 11, indicating that S&box requires a .NET Core 7.0 runtime in order to function. Only a specific subset of the baseline .NET Core complement is available for use.
Security is a primary concern with user content. C# and its ubiquitous pairing with .NET is a software ecosystem many magnitudes larger, more complex, and more powerful than s&box or Source 2. Awarding unchecked access to this leviathan would effectively turn user content into fully-fledged applications with potentially unlimited access to the host computer. To this end, s&box restricts the use of certain types and namespaces. For example, access to the local file system is only available through a sanctioned abstraction layer; System.IO.File and similar types may not be used. This practice is common among applications which attempt to distill down .NET into a limited "scripting" platform for untrusted user code.
Currently, the C# API and tools are in a preview stage of development. Breaking changes happen often and the API is not yet complete.
Todo:
There are many similarities between the use of C# in S&box and the use of the more primitive Lua language in Garry's Mod. Many concepts of Gmod's Lua environment have been carried over, including limited access to the language's features and "hot reloading" of edited code.
S&box will also have a visual scripting solution called ActionGraph, which enables a developer to script events via nodes.
Shaders
Shadergraph UV Rotation Example
You can create your own shaders either through HLSL or through the provided Shadergraph Editor and customize their interface for the material editor.
S&box supports HLSL Shader Model 3.0 up to 5.0.
Todo: Add more detailed information for the shader graph editor.
