createCustomUV.js

/* this.bufferGeometry.setAttribute(
      "uv",
      new THREE.BufferAttribute(uvArray, 2)
    ); 
*/   
createUV(mesh) {
    const box = new THREE.Box3().setFromObject(mesh);
    const size = new THREE.Vector3();

    box.getSize(size);

    const vec3 = new THREE.Vector3();
    const { position, uv } = this.bufferGeometry.attributes;

    for (let i = 0; i < position.count; i++) {
      vec3.fromBufferAttribute(position, i);

      const x = (vec3.x - box.min.x) / size.x;
      const y = (vec3.y - box.min.y) / size.y;

      uv.setXYZ(i, x, y);
    }
  }