不分配新箭头的情况下更新ArrowHelper的困难

我尝试更新的3组件ArrowHelper用three.js。现在，ArrowHelper仅在绘画函数的每次调用中分配新的动画，就可以成功更新动画3 。

例如，在我的main函数中，我首先分配如下3 ArrowHelper：

// Parameters for vector
var directionMainVectorX = new THREE.Vector3(1, 0, 0);
var directionMainVectorY = new THREE.Vector3(0, 1, 0);
var directionMainVectorZ = new THREE.Vector3(0, 0, 1);

var originMainVector = new THREE.Vector3(0, 0, 0);
var lengthVector = 20;
var widthVector = 3;
var headLengthVector = 1.5;
var headWidthVector = 1.5;
var hexVector = 0x11ff00;

mainVectorX = new THREE.ArrowHelper(directionMainVectorX, originMainVector, lengthVector, hexVector, headLengthVector, headWidthVector);
mainVectorY = new THREE.ArrowHelper(directionMainVectorY, originMainVector, lengthVector, hexVector, headLengthVector, headWidthVector);
mainVectorZ = new THREE.ArrowHelper(directionMainVectorZ, originMainVector, lengthVector, hexVector, headLengthVector, headWidthVector);

然后，进入drawVector()函数，我有：

function drawVector() {

  // Parameters for ArrowHelper
  var headLengthVector = 1.5;
  var headWidthVector = 1.5;
  var hexVector = 0x11ff00;
  var widthVector = 3;

  // SOLUTION : Allocating each time a new vector
  mainVectorX = new THREE.ArrowHelper(directionMainVectorX.normalize(), originMainVector, lengthVector, hexVector, headLengthVector, headWidthVector);
  mainVectorY = new THREE.ArrowHelper(directionMainVectorY.normalize(), originMainVector, lengthVector, hexVector, headLengthVector, headWidthVector);
  mainVectorZ = new THREE.ArrowHelper(directionMainVectorZ.normalize(), originMainVector, lengthVector, hexVector, headLengthVector, headWidthVector);

  // Width for mainVector
  mainVectorX.line.material.linewidth = widthVector;    
  mainVectorY.line.material.linewidth = widthVector;    
  mainVectorZ.line.material.linewidth = widthVector;    

  // Add arrows to scene reference
  scene.add(mainVectorX);
  scene.add(mainVectorY);
  scene.add(mainVectorZ);    

}

最后，我的render功能：

function render() {

  rotateCamera();

  drawVector();

  controls.update();

  renderer.render(scene, camera);

  scene.remove(mainVectorX);
  scene.remove(mainVectorY);
  scene.remove(mainVectorZ);

}

使用以上所有代码，一切正常。

我的问题是我不想使用“ allocating at each call of drawVector() function”。

这就是为什么我只分配一次3的原因ArrowHelper（我在main代码的开头进行分配），然后通过使用intodrawVector()函数来更新它们的组件，如下所示：

function drawVector() {

  // Parameters for ArrowHelper
  var headLengthVector = 1.5;
  var headWidthVector = 1.5;
  var hexVector = 0x11ff00;
  var widthVector = 3;

  // Compute coordinates of 3vectors

  // Compute directions
  directionMainVectorX.set(1, 0, 0);
  directionMainVectorY.set(0, 1, 0);  
  directionMainVectorZ.set(0, 0, 1);    

  // Update mainVector

  // SOLUTION : update the parameters of vector
  mainVectorX.position.set(originMainVector);
  mainVectorY.position.set(originMainVector);
  mainVectorZ.position.set(originMainVector);    

  mainVectorX.setDirection(directionMainVectorX.normalize());
  mainVectorY.setDirection(directionMainVectorY.normalize());  
  mainVectorZ.setDirection(directionMainVectorZ.normalize());  

  mainVectorX.setLength(lengthVector, headLengthVector, headWidthVector);
  mainVectorX.setColor(hexVector)

  mainVectorY.setLength(lengthVector, headLengthVector, headWidthVector);
  mainVectorY.setColor(hexVector)

  mainVectorY.setLength(lengthVector, headLengthVector, headWidthVector);
  mainVectorY.setColor(hexVector)    

  // Add arrows to scene reference
  scene.add(mainVectorX);
  scene.add(mainVectorY);
  scene.add(mainVectorZ);    
}

我在上一篇文章中看到了这种方法： update ArrowHelper

但是不幸的是，什么都没有出现，我错过了一些东西，但是我不知道...

如果有人可以帮助我，那就太好了。