ConvexObjectBreaker

This class can be used to subdivide a convex Geometry object into pieces.

Use the function prepareBreakableObject to prepare a Mesh object to be broken. Then, call the various functions to subdivide the object (subdivideByImpact, cutByPlane). Sub-objects that are product of subdivision don't need prepareBreakableObject to be called on them.

Requisites for the object:

  • Mesh object must have a buffer geometry and a material.
  • Vertex normals must be planar (not smoothed).
  • The geometry must be convex (this is not checked in the library). You can create convex geometries with ConvexGeometry. The BoxGeometry, SphereGeometry and other convex primitives can also be used.

Note: This lib adds member variables to object's userData member (see prepareBreakableObject function) Use with caution and read the code when using with other libs.

Import

ConvexObjectBreaker is an addon, and must be imported explicitly, see Installation#Addons.

import { ConvexObjectBreaker } from 'three/addons/misc/ConvexObjectBreaker.js';

Constructor

new ConvexObjectBreaker( minSizeForBreak : number, smallDelta : number )

Constructs a new convex object breaker.

minSizeForBreak

Min size a debris can have to break.

Default is 1.4.
smallDelta

Max distance to consider that a point belongs to a plane.

Default is 0.0001.

Methods

.cutByPlane( object : Object3D, plane : Plane, output : Object ) : number

Subdivides the given 3D object into pieces by a plane.

object

The 3D object to subdivide.
plane

The plane to cut the 3D object.
output

An object that stores the pieces.
Returns: The number of pieces.

.prepareBreakableObject( object : Object3D, mass : number, velocity : Vector3, angularVelocity : Vector3, breakable : boolean )

Must be called for all 3D objects that should be breakable.

object

The 3D object. It must have a convex geometry.
mass

The 3D object's mass in kg. Must be greater than 0.
velocity

The 3D object's velocity.
angularVelocity

The 3D object's angular velocity.
breakable

Whether the 3D object is breakable or not.

.subdivideByImpact( object : Object3D, pointOfImpact : Vector3, normal : Vector3, maxRadialIterations : number, maxRandomIterations : number ) : Array.<Object3D>

Subdivides the given 3D object into pieces by an impact (meaning another object hits the given 3D object at a certain surface point).

object

The 3D object to subdivide.
pointOfImpact

The point of impact.
normal

The impact normal.
maxRadialIterations

Iterations for radial cuts.
maxRandomIterations

Max random iterations for not-radial cuts.
Returns: The array of pieces.

Source

examples/jsm/misc/ConvexObjectBreaker.js