what is box3d-unity fr?

Box3d for Unity is a C# wrapper that brings the Box3d physics engine into the Unity game engine. Box3d is a 3D physics simulation created by Erin Catto, who also created the widely used Box2D engine. This project acts as a bridge, exposing the engine's roughly 580 native C functions in a way that feels natural to Unity developers. The author notes that the wrapper is currently in an early stage and tracks the young Box3d engine, so you should expect changes as the underlying engine updates. The package covers the standard features needed for a physics engine. You can create static, kinematic, and dynamic bodies, and assign them shapes like spheres, capsules, and convex hulls. It includes nine types of joints for connecting objects, such as distance, revolute, and wheel joints with suspension and steering. You can cast rays to detect objects, handle collision events, and use a character mover toolkit for kinematic capsule controllers. The wrapper also includes extras like explosions and wind, plus a debug overlay to visualize shapes, contacts, and forces directly in the Unity editor. A notable feature is its focus on determinism and replay. You can record a simulation and verify that it reproduces the exact same state, even across different numbers of worker threads. This is useful for networked games that use lockstep or rollback netcode, and for reproducing bugs. The engine handles multithreading internally, allowing you to configure the number of workers per world to scale performance across independent groups of objects, such as piles of debris or crowds. Performance comparisons against Unity's built-in PhysX engine show faster processing times in several test scenes. In one test with 10,000 falling spheres, Box3d processed the frame in 1.84 milliseconds compared to PhysX's 6.70 milliseconds. Box3d performs best with scenes that contain many independent piles or crowds, while a single large coupled constraint network is its least favorable scenario. You can install the package through the OpenUPM registry or by providing a Git URL in Unity's Package Manager. It requires Unity 6000.0 or newer and includes native binaries for Windows, Linux, Android, and WebGL. The project ships with several sample scenes, including an interactive playground, a drivable vehicle, and a large pyramid stress test.