Линия

массив точек
const points=[
new THREE.Vector2(0,0),
new THREE.Vector2(1,1),
]
материал с цветом
const material = new THREE.LineBasicMaterial({color:0x00ff00});

const geometry = new THREE.BufferGeometry().setFromPoints(points);
const line = new THREE.Line(geometry ,material );
scene.add(geometry);