Baking world transform

[Samsy]

Hello !

I was reading the doc a could not find a way to bake a world matrix into a geometry position buffer and normals directly, something similar as Three.js :

geometry.applyMatrix4( worldMatrix )

Is there something similar using GLTF-transform ?

[donmccurdy]

Hi @Samsy! Probably what you want is either transformMesh or transformPrimitive:

import { transformMesh, transformPrimitive } from '@gltf-transform/functions';
import { fromScaling } from 'gl-matrix/mat4';

const matrix = fromScaling([], [2, 2, 2]);

// (A) transform mesh
const mesh = document.getRoot().listMeshes();
transformMesh(mesh, matrix);

// (B) transform prim
const prim = mesh.listPrimitives()[0];
transformPrimitive(prim, matrix);

The 4x4 matrix is an array of numbers, as defined in gl-matrix/mat4.

https://gltf-transform.donmccurdy.com/functions.html#transformmesh