glb-rig

A mesh file's triangles for rigging, read with no engine. The same BodyTriangles that loadRigTriangles (rig-build) gives from a Babylon scene, read straight from a GLB's bytes: in Bun or Node, in a worker, in a test, or in a headless export. Hand the result to bodyFromMarkers with a character file's markers and you have its RiggedBody with no scene at all.

import { glbRigTriangles } from 'tosijs-3d/glb-rig'
import { bodyFromMarkers } from 'tosijs-3d/rigged-body'

const bytes = new Uint8Array(await (await fetch(url)).arrayBuffer())
const tris = glbRigTriangles(bytes)
const body = bodyFromMarkers(tris, { markers, source: url })

What it gives, and how it agrees with the Babylon path (a test loads the same files both ways and compares them):

• The file's own frame, right-handed, every node's transform applied. A skinned mesh is taken skinned AT REST (its joints' rest transforms times their inverse bind matrices), its own node's transform ignored, as glTF says and Babylon's loader does: a file in centimetres sized by its armature comes out in metres.
• pick takes one node of a library file and its children, its own translation dropped (so the character stands at the origin), as loadRigTriangles does. A name that is not there throws.
• Surfaces: one run of triangles per material, named as Babylon names them (the material's name, material<i> when it has none, made unique), runs that follow one another with the same material joined. Each carries its glTF material as data (GltfSurfaceMaterial): the PBR factors, alpha mode, two-sidedness, and each texture's IMAGE BYTES and MIME type (a data: URI decoded; an external uri kept as it is, unread).
• Eyes: meshes named as eyes (isEyeName) are kept out of the body and handed back as eyes, one per side, as splitEyes does.
• Uvs and colours when any mesh has them (others filled with 0 and white, as the Babylon path fills them); colours as RGBA floats.

Only triangle lists are read (mode 4, the default); other primitives (lines, points, strips) are skipped. Compressed geometry (Draco, meshopt) is not read: it throws, naming the extension.

The rig from it is DETERMINISTIC: the same bytes and the same markers give the same weights, so a saved character exports the same every time.