Chapter 320: BoxHelper

Core Idea

Helper object to graphically show the world-axis-aligned bounding box around an object. The actual bounding box is handled with Box3, this is just a visual helper for debugging. It can be automatically resized with BoxHelper#update when the object it's created from is transformed. Note that the object must have a geometry for this to work, so it won't work with sprites.

Key Concepts

object : Object3D: The 3D object being visualized.

Code Examples

const sphere = new THREE.SphereGeometry();
const object = new THREE.Mesh( sphere, new THREE.MeshBasicMaterial( 0xff0000 ) );
const box = new THREE.BoxHelper( object, 0xffff00 );
scene.add( box );

What it demonstrates: Typical usage of BoxHelper.

Reference Tables

Constructor

Signature
`new BoxHelper( object : Object3D, color : number

Properties

Property	Description
`.object : Object3D`	The 3D object being visualized.

Methods

Method	Description
`.dispose()`	Frees the GPU-related resources allocated by this instance. Call this method whenever this instance is no longer used in your app.
`.setFromObject( object : Object3D ) : BoxHelper`	Updates the wireframe box for the passed object.
`.update()`	Updates the helper's geometry to match the dimensions of the object, including any children.

Key Takeaways

BoxHelper extends: EventDispatcher → Object3D → Line → LineSegments
Most relevant properties: object.
Key methods: dispose, setFromObject, update.

Connects To

EventDispatcher: parent class
Object3D: parent class
Line: parent class
LineSegments: parent class
Source: src/helpers/BoxHelper.js