Box3D

Box3D is a 3D physics engine for games.

Build status

Features

Collision

• Continuous collision detection
• Contact events
• Convex hulls, capsules, spheres, triangle meshes, and height fields
• Multiple shapes per body
• Collision filtering
• Ray casts, shape casts, and overlap queries
• Sensor system

Physics

• Robust Soft Step rigid body solver
• Continuous physics for fast translations and rotations
• Island based sleep
• Revolute, prismatic, distance, mouse joint, weld, and wheel joints
• Joint limits, motors, springs, and friction
• Joint and contact forces
• Body movement events and sleep notification

System

• Data-oriented design
• Written in portable C17
• Extensive multithreading and SIMD
• Optimized for large piles of bodies

Samples

• Uses sokol to run with D3D11 on Window, Metal on macOS, and OpenGL 4.3 on Linux
• Graphical user interface with imgui
• Many samples to demonstrate features and performance

Building all platforms

• Install CMake
• Install git
• Ensure these run from the command line

Building with CMake presets (recommended)

The presets in CMakePresets.json give one build flow on every platform and are picked up automatically by Visual Studio, VS Code, and CLion (open the folder and choose a preset). From the command line:

• Windows: cmake --preset windows then cmake --build --preset windows-release
• Linux: cmake --preset linux-release then cmake --build --preset linux-release
• macOS: cmake --preset macos then cmake --build --preset macos-release

Run the samples app (must be in the Box3D directory).

• Windows: .\build\bin\Release\samples.exe
• Linux: ./build/bin/samples
• macOS: ./build/bin/Release/samples

Building for Visual Studio

• Install Visual Studio
• Run build_vs2026.bat
• Open and build build/box3d.slnx

Building for Linux

• Run build.sh from a bash shell
• Results are in the build sub-folder

Building for Xcode

• mkdir build
• cd build
• cmake -G Xcode ..
• Open box3d.xcodeproj
• Select the samples scheme
• Build and run the samples

Building and installing

• mkdir build
• cd build
• cmake ..
• cmake --build . --config Release
• cmake --install . (might need sudo)

Using Box3D in your project

The core library has no dependencies beyond the C runtime (and libm on Unix). Linking it gives you the box3d::box3d target. When Box3D is consumed as a subproject it builds the library only; samples, tests, and benchmarks are skipped.

The recommended path is FetchContent, which pins a tag and needs no separate install step:

include(FetchContent)
FetchContent_Declare(box3d
  GIT_REPOSITORY https://github.com/erincatto/box3d.git
  GIT_TAG v0.1.0)
FetchContent_MakeAvailable(box3d)

target_link_libraries(my_app PRIVATE box3d::box3d)

For a vendored copy or git submodule, point add_subdirectory at it:

add_subdirectory(extern/box3d)

target_link_libraries(my_app PRIVATE box3d::box3d)

To use a copy installed with cmake --install, find the package:

find_package(box3d 0.1 REQUIRED)

target_link_libraries(my_app PRIVATE box3d::box3d)

See docs/hello.md for a minimal first program.

Compatibility

The Box3D library and samples build and run on Windows, Linux, and Mac.

You will need a compiler that supports C17 to build the Box3D library.

You will need a compiler that supports C++20 to build the samples.

Box3D uses SSE2 and Neon SIMD math to improve performance. This can be disabled by defining BOX3D_DISABLE_SIMD.

Documentation

The user manual lives in docs/ and is built with Doxygen. Enable the BOX3D_DOCS CMake option and build the doc target.

Community

• Discord

Contributing

Please do not submit pull requests. Instead, please file an issue for bugs or feature requests. For support, please visit the Discord server.

Giving feedback

Please file an issue or start a chat on discord. You can also use GitHub Discussions.

License

Box3D is developed by Erin Catto and uses the MIT license.

Sponsorship

Support development of Box3D through Github Sponsors.

Please consider starring this repository and subscribing to my YouTube channel.