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Basic Concepts

Get a high-level picture of how KawaiiPhysics works and how its settings fit together. Each element links to its dedicated setup guide or reference.

Architecture

KawaiiPhysics achieves bone physics using its own lightweight algorithm without using PhysX. It runs as a node in the AnimGraph, taking the input pose and outputting the pose after physics simulation.

Architecture and data flow

Position of the KawaiiPhysics node within the AnimGraph and its internal processing flow (diagram labels are in Japanese).

Overview of the Building Blocks

KawaiiPhysics setup is made up of the following elements.

ElementSummaryLearn more
Bone ChainThe range of bones that physics is applied to, starting from the Root Bone. Exclude Bones can remove part of itBone Chain Setup
Physics ParametersDamping (how quickly it settles) / Stiffness (how strongly it returns) / Radius (thickness) decide how it swaysAdjusting the Sway
CollisionSphere, capsule, box, and plane shapes prevent body penetrationCollision Setup
CurvesSmoothly vary parameters from root to tipCurve Editor
External ForcesApply wind, gravity, or arbitrary forcesWind and External Forces

Next Steps

Once you have the big picture, move on to the setup guides based on what you want to do.

  1. Bone Chain Setup — specify which bones to sway
  2. Adjusting the Sway — decide how it sways with Damping / Stiffness / Radius
  3. Collision Setup — prevent body penetration
  4. Wind and External Forces — apply wind and gravity

For a full list of parameters, see the Parameters Overview.