three.js/examples/js/modifiers/ExplodeModifier.js

console.warn( "THREE.ExplodeModifier: As part of the transition to ES6 Modules, the files in 'examples/js' were deprecated in May 2020 (r117) and will be deleted in December 2020 (r124). You can find more information about developing using ES6 Modules in https://threejs.org/docs/#manual/en/introduction/Installation." );
/**
 * Make all faces use unique vertices
 * so that each face can be separated from others
 */

THREE.ExplodeModifier = function () {

};

THREE.ExplodeModifier.prototype.modify = function ( geometry ) {

	var vertices = [];

	for ( var i = 0, il = geometry.faces.length; i < il; i ++ ) {

		var n = vertices.length;

		var face = geometry.faces[ i ];

		var a = face.a;
		var b = face.b;
		var c = face.c;

		var va = geometry.vertices[ a ];
		var vb = geometry.vertices[ b ];
		var vc = geometry.vertices[ c ];

		vertices.push( va.clone() );
		vertices.push( vb.clone() );
		vertices.push( vc.clone() );

		face.a = n;
		face.b = n + 1;
		face.c = n + 2;

	}

	geometry.vertices = vertices;

};