Spine animation notes, from measured rigs
What we learned building an AI that rigs and animates Spine 4.2 skeletons: numbers counted in the official Spine examples, the traps of the JSON format, and how the tricks work inside.
Rigging a slot game character in Riggy: the Qubix hacker cat, prompt by prompt
The hacker cat of Qubix: Glitch City, rigged by chat from a layered PSD: a celebration loop in two prompts, and the real prompts behind each animation.
From a layered PSD to an animated Spine character in Unity
Install spine-unity 4.2, rename the atlas to .atlas.txt, set straight alpha, drag the SkeletonData into the scene and play animations from C#. Files included.
From a layered PSD to an animated Spine character in PixiJS 8
Rig a layered PSD, export Spine 4.2 JSON and play it in PixiJS 8 with the official spine-pixi-v8 runtime: Assets loading, playing, mixing, one-shots. Live demo.
From a layered PSD to an animated Spine character in Phaser 4
Rig a layered PSD, export Spine 4.2 JSON and play it in Phaser 4 with the official spine-phaser-v4 plugin: loading, playing, mixing, one-shots. Live demo.
Idle animation timing, measured on 127 official Spine animations
Frame grid, idle length, key density, rotation ranges by bone role, loop closure and curves — counted in the official Spine 4.2 example skeletons.
How we generate Spine 4.2 JSON with an LLM
The model never writes skeleton.json: it calls intent-level tools, code measures the art, a validator and the official runtime check each file. Traps we hit.
Pseudo-3D head turn from a flat image in Spine
How a single flat image turns in Spine as if it had volume: a mesh, a relief, a perspective projection and deform keys — and why it stops working past 45°.
Spine 4.2 Bezier curves in JSON, explained
What the curve array of a Spine 4.x timeline means: absolute time and value, four numbers per component, stepped, linear, and why 3.8 curves break in 4.2.