Three.js根据内部网格设置Object3D的中心答案

【问题标题】：Three.js set the center of a Object3D based on internal meshesThree.js根据内部网格设置Object3D的中心
【发布时间】：2021-08-13 13:45:09
【问题描述】：

当我得到未以对象为中心的顶点时，我有一个位于 Object3D 中的网格集。所以我需要计算 object3D 的中心，然后移动网格以将它们与中心对齐。我尝试计算每个网格的边界框，然后是 max - min /2；这不起作用。这里的任何帮助都会很棒。我试过 Object3D.setFromObject();这只会返回无穷大。

【问题讨论】：

你能分享一些代码吗？有点难以想象你的问题......

标签： three.js

【解决方案1】：

据我所知，要使 Object3D 居中，取决于它的子对象，您必须遍历它们。代码如下所示：

// myObject3D is your Object3D

var children = myObject3D.children,
  completeBoundingBox = new THREE.Box3(); // create a new box which will contain the entire values

for(var i = 0, j = children.length; i < j; i++){ // iterate through the children

  children[i].geometry.computeBoundingBox(); // compute the bounding box of the the meshes geometry

  var box = children[i].geometry.boundingBox.clone(); // clone the calculated bounding box, because we have to translate it

  box.translate(children[i].position); // translate the geometries bounding box by the meshes position

  completeBoundingBox.addPoint(box.max).addPoint(box.min); // add the max and min values to your completeBoundingBox

}

var objectCenter = completeBoundingBox.center()

console.log('This is the center of your Object3D:', objectCenter );

// You want the center of you bounding box to be at 0|0|0

myObject3D.position.x -= objectCenter.x;
myObject3D.position.y -= objectCenter.y;
myObject3D.position.z -= objectCenter.z;

希望我能正确理解您的问题！

【讨论】：

【解决方案2】：

center = function(obj) {
  var children = obj.children,
  completeBoundingBox = new THREE.Box3();
  for(var i = 0, j = children.length; i < j; i++) {
    children[i].geometry.computeBoundingBox();
    var box = children[i].geometry.boundingBox.clone();
    box.translate(children[i].position);
    completeBoundingBox.set(box.max, box.min);
  }
  var objectCenter = completeBoundingBox.center()
  console.log('This is the center of your Object3D:', objectCenter );
  obj.position.x -= objectCenter.x;
  obj.position.y -= objectCenter.y;
  obj.position.z -= objectCenter.z;
}

【讨论】：

你能添加 cmets 来解释你的代码在做什么吗？
center(obj) obj -- Object3D -- 显示世界轴对齐边界框的 object3D。这以 Object3D 为中心。