Hi everyone — I'm very proud to share the progress I’ve made on a project I’ve been developing for quite some time.

Video demonstration:
https://odysee.com/@DigitalArtFreedom:6/EP-0001_Blender-Spine-IO_pre-release:2?r=5uzb4Nk5x5zfozjYh3NkgAWtx5PDSyg3

Blender-Spine-IO — Release v0.0.1 (Alpha)

Open-source Spine 4.3 JSON exporter for Blender (OCA/OCO-friendly)
Author: Simon Heggie • Blender 4.2+ • Spine 4.3.39-beta • License: GPL-3.0

This project provides a direct Blender → Spine pipeline, supporting meshes, bones, weights, FK animation, blend modes, correct internal edges, OCA/OCO texture routing, and more. Import features are planned for later versions.

DOWNLOAD:

SimonHeggie/Blender-Spine-IOreleases/download/v0.0.1_pre-release/blender_spine_io_v0.0.1_pre-release.zip

Installation

Extensions (recommended):
Blender → Edit → Preferences → Extensions → Install ZIP → Enable Blender-Spine-IO

Legacy Add-on:
Preferences → Add-ons → Install… → Enable Spine-IO

Where It Appears

File → Export → Spine (.json) — full export dialog
3D Viewport → Sidebar → Spine-IO tab
Quick Export (stores last path)
Texture export toggle
Blend-Mode Manager

Features (Working as of v0.0.1)

✔ Mesh Export

Tris/quads/ngons
Internal edges (Spine-compatible)
Correct hull detection
Works on weighted/unweighted meshes

✔ Armature & Bones

Full hierarchy
Correct local transforms
Bone lengths
Auto-scale or constant-scale

✔ Weights

Up to 4 influences
Fallback bones
Correct Spine-space export

✔ Animation (FK)

Exports the active Action
Spine-compatible timelines

✔ Materials → Spine Blend-Modes

Procedural BLEND-MODE node
Normal / Additive / Multiply / Screen

✔ Tools / UI

One-click Quick Export
Blend-mode sync
Simple material browser

✔ OCA/OCO Pathing

Removes *.OCA wrappers
Normalizes nested folders
Predictable texture mapping

✔ Parenting Fix

Unparented weighted meshes auto-bind correctly.

Known Issues

Occasional UI slowdown (material scanning)
Root bone requires 90° workaround — full transform fix planned
FK-only animation (IK/constraints planned)
Unweighted meshes appear at origin

Roadmap

🔥 High Priority

Correct world→Spine transform
Controller bones
Drivers (e.g., alpha)
IK & constraints

🔥 Medium

Multi-Action export
Skins + slot colours
2-colour tint
PSD/Krita layer-name → slot mapping

🔥 Low

Full Spine → Blender importer
Unified UI for multi-rig workflows

Source & Extension Review

Currently awaiting review on the Blender Extensions site:
https://extensions.blender.org/approval-queue/blender-spine-io/

Acknowledgements & Notes on Credit

I want to thank the Spine team for answering licensing questions and providing helpful pointers.

For transparency: the only external implementation I directly studied for weighted mesh handling — specifically internal edges and hull encoding — was maximsokal’s work. Everything else (rig-space transforms, animation export, materials, OCA/OCO routing, UI, utility architecture, etc.) is original work I’ve designed and written for this project - based on my interpretation of Esoteric's .JSON documentation.

Since this topic came up on the forum early in my development, I wanted to share this release now so there is a clear public record of the features, solutions, and implementation I’ve built so far.

As this project is GPL-3.0, you are free to build upon it — all I ask is that derivative work provides appropriate credit, which is standard practice and important for creative and technical careers.

Collaboration

My aim is to build a reputation as someone who is indispensable at providing smart solutions.
But I'm open to where my work can build a part of a bigger solution.

I’m absolutely open to collaborating. If the Spine team or community developers wish to work together, I’m happy to coordinate so we don’t duplicate effort or reinvent the wheel in parallel. If not, I’m committed to continuing development on my version.

Thanks for taking the time to look, and I hope this exporter becomes a valuable tool for the community.

– Simon