UVsDebug is an addon, and must be imported explicitly, see Installation#Addons.
import { UVsDebug } from 'three/addons/utils/UVsDebug.js';
Function for "unwrapping" and debugging three.js geometries UV mapping.
document.body.appendChild( UVsDebug( new THREE.SphereGeometry() ) );
geometry
The geometry whose uv coordinates should be inspected.
size
The size of the debug canvas.
Default is 1024.
Returns: A canvas element with visualized uv coordinates.