Obi is the first CPU-based realtime particle physics engine for Unity:
The most advanced cloth simulator for Unity. It brings back and improves pre-5.x cloth functionality.
Obi Rope will allow you to create realistic ropes and chains fast, with absolute control over their look.
Obi Fluid is a fully-fledged 2D and 3D realtime fluid simulator for Unity.
New in versión 4, released in January 2019. A high-quality, high-performance soft body simulator based on cutting-edge technology.
Simulate complex softbody meshes composed of thousands of polygons, complete with collisions, self-collisions and rigid body interaction.