Existing armature setup
Discover hierarchies, branching chains, multiple roots, rig problems, and virtual endpoints through the guided setup wizard.
All assets
Secondary motion without the rigging tax
Reactive Bones
Create the rig. Tune the motion. Add the collision you need.
A complete bone-based secondary motion toolkit for hair, tails, ears, straps, cables, soft-body motion, plants, and accessories—with setup wizards, rig painting, smart collision, wind, runtime forces, optimization, and debugging.
Rig painterSmart collisionWind + forcesRuntime budgets
Existing rigsChain discovery and setup wizard
No rigPaint and generate one in Unity
CollisionCharacter volumes and Unity Colliders
ScaleCulling, sleeping, and world budgets
What it solves
Create the rig. Tune the motion. Add the collision you need.
Reactive Bones is built around a visual, editor-first workflow. Use bones a model already has, or paint reactive regions directly onto a Mesh Renderer or Skinned Mesh Renderer and generate the bones, skin weights, and chains inside Unity.
From there, reusable profiles, centralized collision planning, ordinary Unity Collider interaction, wind, runtime forces, culling, and live diagnostics turn secondary motion into a system you can actually ship.
Core capabilities
A complete workflow, not a single trick.
The package connects authoring, runtime behavior, and the controls needed to integrate it into a real game.
Reactive Rig Painter
Paint hair, tail, or jiggle regions and generate bones, weights, chains, falloff, centerlines, and mirrored layers inside Unity.
Smart Collision Manager
Analyze characters, plan sparse capsule coverage, add manual volumes, preserve hand edits, and synchronize modular pieces.
Direct world collision
Interact with ordinary Unity Colliders using layer filters, trigger rules, self-collision rejection, friction, and broadphase limits.
Wind and runtime forces
Drive motion with global, spherical, or box wind zones plus persistent forces and one-shot impulses from gameplay code.
Production runtime controls
Use distance and visibility culling, smooth sleep and wake, teleport recovery, solver substeps, and adaptive simulation budgets.
The path through the tool
From first setup to production behavior.
The exact controls differ, but each STL Dynamics system is structured to get a first result quickly and leave enough depth for serious tuning.
Open Reactive Bones docsFind or build the rig
Run the setup wizard on existing bones, or paint a mesh region and generate a non-destructive reactive rig.
Shape the response
Assign reusable physics profiles and tune damping, elasticity, stiffness, inertia, gravity, limits, and root-to-tip curves.
Connect it to the world
Plan character collision, enable selected Unity Collider interaction, add wind, and verify contacts and budgets live.
Product showcase
Inside Reactive Bones.
Real editor workflows, runtime demos, feature breakdowns, and package presentation from the included media.
Watch it work
See the workflow in motion.
Open the official STL Dynamics videos on YouTube for the complete walkthrough and focused tutorials.
▶Official videoReactive Bones Showcase
Dynamic bone physics, collision, tooling, and runtime behavior.
Watch on YouTube ↗ ▶Official videoCreate Reactive Rigs in UnityPaint a mesh and generate a working reactive rig without leaving Unity.
Watch on YouTube ↗ ▶Official videoSet Up Hair CollisionsA focused walkthrough for character and hair collision setup.
Watch on YouTube ↗ Documentation included
Go from first setup to the exact system you need.
7 focused documents are available in the STL Dynamics documentation hub for Reactive Bones.
More from STL Dynamics
Explore the rest of the lineup.
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Define reusable SoundEvents, route playback through one managed pool, and keep large scenes under control with distance behavior, voice limits, loop virtualization, mixer routing, and runtime diagnostics.
2D + 3DPooling
Water + VFX
Retro Water System for URP
Build lakes, rivers, pools, swamps, and bounded oceans with profile-driven retro rendering, CPU surface sampling, Rigidbody buoyancy, projected caustics, underwater effects, and tiled-ocean LOD.
URPBuoyancy
Character Rendering
Human Shaders for URP
A complete URP character material toolkit with specialized human shaders, one editor workspace, texture packing, reusable profiles, diagnostics, runtime controls, and painted or geometric skin visibility workflows.
URPSix shader families