cd ~/tools
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Spine Animator Toolkit

Spine 2D in Unity, with zero runtime

WindowsmacOSLinux (Unity Editor)
Read the docsSupport
Spine Animator Toolkit · Batch Convert
hero.skel
hero.atlas
hero.png
Spine
baked
Clips
Controller
Prefab
Unity
0 KB runtime
// README.md

# Overview

Spine Animator Toolkit converts skeletal animations from Spine (the industry-standard 2D animation tool) into native Unity assets: AnimationClips, an AnimatorController, and a ready-to-play Prefab. Once converted, your project no longer depends on the Spine runtime, your animations are just plain Unity. Smaller builds, faster load times, and every Unity feature (Timeline, Mecanim, Animation Rigging, URP / HDRP / Built-in, Addressables) just works.

  • One-click batch conversion of every rig in your project
  • Three output modes: atlas-sliced sprites, separate PNGs, or SkinnedMeshRenderer
  • Dual-prefab output (sprites + skinned mesh side by side)
  • Pixel-perfect post-constraint curve baking (IK, transform, path, physics)
  • Built-in importer for raw Spine sources (.skel / .json + .atlas + .png)
  • Per-vertex bone weights and BlendShape deform support
  • In-editor bone, mesh, and weight-paint scene tools
  • Works with Timeline, Mecanim, Animation Rigging, URP / HDRP / Built-in
spec.json
{
  "name": "Spine Animator Toolkit",
  "stack": "C# / Unity Editor",
  "platforms": ["Windows", "macOS", "Linux (Unity Editor)"],
  "license": "One-time purchase (Unity Asset Store EULA)",
  "support": "Email + online docs"
}
// ARCHITECTURE.md

# Under the hood

  1. 1Two Unity assemblies: SpineAnimatorToolkit.Runtime + SpineAnimatorToolkit.Editor
  2. 2Vendored spine-csharp parser for Spine source ingestion
  3. 3Intermediate rig.json format for converter / baker decoupling
  4. 4Offline baker emits standard Unity AnimationClips + AnimatorController + Prefab
  5. 5Zero runtime dependency in shipped builds

./capabilities

  • Reads Spine .skel (binary) and .json sources
  • Supports bones, slots, skins, IK, transform / path / physics constraints
  • Atlas reuse with sliced sprites, or per-attachment PNG export
  • SkinnedMeshRenderer mode with per-vertex bone weights and BlendShape deform
  • Per-rig overrides and project-wide defaults (frame rate, atlas policy, default mode)
// DEVLOG.md

# How we built it

./challenges

  • Faithfully reproducing Spine's post-constraint pose at every frame
  • Bridging Spine's pose-relative animation curves to Unity's absolute-keyframe model
  • Supporting both atlas-sliced sprite output and SkinnedMesh skinning from one source
  • Keeping the converted output free of any runtime dependency on Spine or on the toolkit itself

./insights

  • Baking constraints into curves trades a tiny disk-size cost for zero runtime CPU
  • Treating SpriteRenderer and SkinnedMeshRenderer as parallel back-ends, not alternatives, gives developers quality-tier flexibility for free
  • Vendoring spine-csharp inside the editor assembly keeps imports reproducible without forcing customers to manage a second package
Unity 2021.3+ (Mono runtime)C# (.NET Standard 2.1)Vendored spine-csharp parserStandard Unity AnimationClip / AnimatorController APIs
// docs/

# Documentation

Read the full documentationQuickstart, output modes, scripting API, troubleshooting & FAQ.

./guides

  • Quickstart: convert your first Spine rig in 60 seconds
  • Output modes explained: Sprites vs Separate vs SkinnedMesh
  • Batch building every rig in your project
  • Per-rig overrides and project-wide settings
  • Working with Timeline, Mecanim and Animation Rigging on baked output
  • Troubleshooting and FAQ

./examples

  • Basic Rig Walkthrough (bundled sample)
  • Dual-prefab quality tiers (Sprite + SkinnedMesh)
  • Driving a baked rig from a Mecanim state machine

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