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Li physics module overview

Physics for the Li game engine ships as li-physics-* workspace packages on li-math and li-math-numerics, with ergonomic imports (import physics.runtime, import math).

Quick start: GAME_DEV.md (packages, tier-2 benches, engine checklist).

Org mirrors: some published repos still use legacy names (li-std-math, li-httpd). Monorepo folders and import_name values use li-math, li-physics-*, etc. See repo-naming.md.

Fidelity tiers

Tier Name Typical use
T0 Arcade 60+ FPS, PBD, semi-implicit Euler
T1 Simulation Verlet, SPH, weather advection
T2 Scientific FDTD, TDSE, weak-field GR
T3 Research Offline HEP toys, full MD research

Scenes select a PhysicsProfile (tier, dt, substeps, NumericalTargets).

Packages (monorepo packages/)

Folder Import Role
li-math import math Vec3, Quat, Mat4, array dot/sum
li-math-numerics import math.numerics Integrators, three-body reference
li-physics-core import physics.core Profiles, tier defaults
li-physics-rigid import physics.rigid Rigid bodies, PGS stub
li-physics-runtime import physics.runtime PhysicsWorld, physics_step
li-physics-particles import physics.particles Emitters, MD SoA
li-physics-fluids import physics.fluids SPH, heat, cloth PBD
li-physics-weather import physics.weather Advection/diffusion wind
li-physics-aero import physics.aero Atmosphere, orbits
li-physics-chem import physics.chem Reactions, passive combustion
li-physics-em import physics.em Coulomb, FDTD, Poisson
li-physics-quantum import physics.quantum TDSE 1D hooks
li-physics-relativity import physics.relativity SR + Schwarzschild factor
li-physics-hep import physics.hep Toy MC (education)

Benchmarks

Tier-2 kernels live under lic/benchmarks/tier2_physics/. Status is tracked on the benchmarks dashboard.

Numerical policy

See numerical-policy.md for compile-time method selection (planned language phase PHY-n).