Rapier is a set of 2D and 3D physics engines for the Rust programming language focused on performance.
Rapier addresses the need for efficient physics simulation in games, animation, and robotics by providing separate crates for 2D and 3D scenarios, each available in both single-precision and double-precision floating-point variants. The engine prioritizes performance through SIMD-batched constraint solving and contact processing that runs by default, with an optional parallel feature enabling multithreading of the entire physics step across broad phase, narrow phase, and solver stages via rayon. On heterogeneous-core processors, the tool supports pinning work to performance cores to avoid bottlenecks from efficiency cores.
Rapier suits projects requiring physics simulation in Rust where performance matters. The tool is particularly relevant for game developers and robotics applications needing both 2D and 3D capabilities. Python bindings are available for projects that need to integrate physics simulation into Python codebases. The README does not compare Rapier to alternative physics engines, so no comparative guidance can be offered.
The project maintains a substantial base of adopters who report issues from real-world use rather than the core team driving the issue agenda. However, responses to issues and pull requests often wait weeks or longer for initial attention. Work in the issue tracker concentrates on bug fixes and dynamics-related features, with most issues classified as medium difficulty.
