Lightweight bone physics for Unreal Engine: an AnimGraph node that adds secondary motion to hair, skirts, tails, ears and accessories without setting up a Physics Asset or a cloth simulation. It is a pseudo-physics solver tuned for stylised characters, cheap enough to run on many characters at once. The GitHub source is MIT licensed and can ship inside a closed commercial game.
At a glance
Licence
MIT
Commercial use
commercial OK
Credit
Not required
Status
active: License spot-checked at the source; the entry carries dated evidence.
Used from an Animation Blueprint: add the KawaiiPhysics node to the AnimGraph and point it at a root bone; parameters and external forces (wind, gravity) can be driven at runtime from Blueprint or C++
Supported versions come from the README, which states "Unreal Engine 5.3 ~ 5.8"; the last UE4 release is v1.11.1 for UE 4.27, linked from the README
Install by copying Plugins/KawaiiPhysics from the repository or a release into your project's Plugins folder; the repository root is a sample project with one example level per feature
The README warns that packaging a Blueprint-only project can fail; converting to a C++ project (add any C++ class) is the stated fix
A Fab listing exists and the README says it is "Same content as the GitHub version"; the paid listing is a way to support the author, the GitHub copy is the free one
MIT is compatible with the Unreal Engine EULA, which forbids combining engine code with copyleft licences such as GPL and LGPL; keep the copyright notice in your third-party credits
Maintenance: GitHub API (2026-10-13) reports the repository not archived, last push 2026-10-01; latest release v1.21.0 (2026-06-23)
Evidence
LICENSE in the repository, master branch (2026-10-13): "MIT License Copyright (c) 2019-2026 pafuhana1213"
Same file (2026-10-13): "to deal in the Software without restriction"