Computes the bounding sphere of a gltf model
const fs = require('fs');
const gltfBoundingSphere = require('gltf-boundingsphere');
var gltf = fs.readFileSync('box.gltf');
const model = JSON.parse(gltf, 'utf8');
const boundingSphere = gltfBoundingSphere.computeBoundingSphere(model);
// BoundingSphere {
// center: Cartesian3 { x: 0, y: 0, z: 0 },
// radius: 0.8660254037844386
// }