three.js/src/extras/helpers/AxisHelper.js

/**
 * @author sroucheray / http://sroucheray.org/
 * @author mrdoob / http://mrdoob.com/
 */

THREE.AxisHelper = function ( size ) {

	size = size || 1;

	var vertices = new Float32Array( [
		0, 0, 0,  size, 0, 0,
		0, 0, 0,  0, size, 0,
		0, 0, 0,  0, 0, size
	] );

	var colors = new Float32Array( [
		1, 0, 0,  1, 0.6, 0,
		0, 1, 0,  0.6, 1, 0,
		0, 0, 1,  0, 0.6, 1
	] );

	var geometry = new THREE.BufferGeometry();
	geometry.addAttribute( 'position', new THREE.BufferAttribute( vertices, 3 ) );
	geometry.addAttribute( 'color', new THREE.BufferAttribute( colors, 3 ) );

	var material = new THREE.LineBasicMaterial( { vertexColors: THREE.VertexColors } );

	THREE.Line.call( this, geometry, material, THREE.LinePieces );

};

THREE.AxisHelper.prototype = Object.create( THREE.Line.prototype );
THREE.AxisHelper.prototype.constructor = THREE.AxisHelper;