var scene = new THREE.Scene();

            var camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 1, 1500);

            camera.lookAt(new THREE.Vector3(0, 0, 0));

            camera.position.set(0, 0, 100);

​

​

​

            var renderer = new THREE.WebGLRenderer({alpha:true});

            renderer.setSize(window.innerWidth, window.innerHeight);

            document.body.appendChild(renderer.domElement);

​

​

            var world;

            world = new THREE.Object3D();

            scene.add( world );

​

            // arrow vector helper

            var origin = new THREE.Vector3(0, 10, 0);

            var direction = new THREE.Vector3(80, 10, 0);

            direction.normalize();

            var length = 12;

            var hex = 0x000000;

            var arrowHelper = new THREE.ArrowHelper( direction, origin, length, hex );

            world.add( arrowHelper );

            /*

                direction after its normalized

                Object

                x: 0.9922778767136676

                y: 0.12403473458920845

                z: 0

            */

​

​

​

            // laser from front

            var lasermat = new THREE.LineBasicMaterial({

                    color: 0x248aff,

                    linewidth: 8

                });

            var lasergeo = new THREE.Geometry();

                lasergeo.vertices.push(new THREE.Vector3(0, 10, 0));

                lasergeo.vertices.push(new THREE.Vector3(80, 10, 0));

            var laser = new THREE.Line(lasergeo, lasermat);

            world.add( laser );

​

​

​

            var render = function () {

                requestAnimationFrame(render);

                renderer.render(scene, camera);

            };

            render();

​

​

​