var positions = new Float32Array(geometry.__directGeometry.vertices.length * 3);
geometry._bufferGeometry.setAttribute('position', new THREE.BufferAttribute(positions, 3).copyVector3sArray(geometry.__directGeometry.vertices));
Это верно
geometry._bufferGeometry.getAttribute('position').copyVector3sArray(geometry.__directGeometry.vertices);
geometry._bufferGeometry.getAttribute('position').needsUpdate = true;
это неверно, не знаю почему, три. js v119