ecto / phyz

What is phyz?

Phyz is a Rust-based differentiable physics engine that runs multi-physics simulations—rigid bodies, SPH fluids, electromagnetism on Yee grids, even Regge calculus for general relativity—all with analytical Jacobians for gradient-based optimization. Load MJCF models, batch thousands of GPU-accelerated envs via WGPU, and get derivatives through full trajectories for controller tuning or parameter fitting from video. It turns physics into a true differentiable function, skipping noisy finite differences.

Why is it gaining traction?

Unlike standard engines, phyz delivers end-to-end differentiability across domains like differentiable physics simulation of dynamics augmented neural objects or differentiable physics enabled closure modeling for burgers turbulence, with kernel fusion slashing GPU memory use. Rust ensures zero-cost safety at C++ speeds, while MJCF import and probabilistic inference (SVGD/HMC) hook ML workflows. Devs dig the one-loop sim+grads for differentiable physics and stable modes for tool use and manipulation planning.

Who should use this?

Robotics researchers optimizing manipulation planners with differentiable physics models for real-world offline model-based reinforcement learning. Audio engineers reconstructing sound fields via differentiable physics for sound field reconstruction. Sim hackers blending EM/rigid for Lorentz-coupled actuators or differentiable ray tracing github prototypes.

Verdict

Promising differentiable physics engine at 1.0% credibility (11 stars, solid tests, thin docs)—use for proofs-of-concept now, but wait for benchmarks and examples before prod. Fork-friendly MIT for custom physics tweaks.

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