Three.js

Create a new mesh from faces projections of another mesh.

HTML

<script src="https://dl.dropboxusercontent.com/s/a7rgtxhskh397sh/three.min.js"></script>
<script src="https://dl.dropboxusercontent.com/s/8jejk094rdssb5q/STLLoader.js"></script>
<script src="https://dl.dropboxusercontent.com/s/f163vrsa79ad8i1/OrbitControls.js"></script>

CSS

body {
    margin: 0;
    background: #000;
}
div{
		border: 1px solid green;
		width: 600px;
		height: 400px;
}

JavaScript

var container, stats;
var camera, controls, scene, renderer;
var pickingData = [], pickingTexture, pickingScene;
var highlightBox;
var mouse = new THREE.Vector2();
var offset = new THREE.Vector3( 10, 10, 10 );
init();
animate();
function init() {
	container = document.getElementById( "container" );
	camera = new THREE.PerspectiveCamera( 70, window.innerWidth / window.innerHeight, 1, 10000 );
	camera.position.z = 1000;
	controls = new THREE.TrackballControls( camera );
	controls.rotateSpeed = 1.0;
	controls.zoomSpeed = 1.2;
	controls.panSpeed = 0.8;
	controls.noZoom = false;
	controls.noPan = false;
	controls.staticMoving = true;
	controls.dynamicDampingFactor = 0.3;
	scene = new THREE.Scene();
	scene.background = new THREE.Color( 0xffffff );
	pickingScene = new THREE.Scene();
	pickingTexture = new THREE.WebGLRenderTarget( window.innerWidth, window.innerHeight );
	pickingTexture.texture.minFilter = THREE.LinearFilter;
	scene.add( new THREE.AmbientLight( 0x555555 ) );
	var light = new THREE.SpotLight( 0xffffff, 1.5 );
	light.position.set( 0, 500, 2000 );
	scene.add( light );
	var pickingMaterial = new THREE.MeshBasicMaterial( { vertexColors: THREE.VertexColors } );
	var defaultMaterial = new THREE.MeshPhongMaterial( { color: 0xffffff, flatShading: true, vertexColors: THREE.VertexColors, shininess: 0	} );
	function applyVertexColors( geometry, color ) {
		var position = geometry.attributes.position;
		var colors = [];
		for ( var i = 0; i < position.count; i ++ ) {
			colors.push( color.r, color.g, color.b );
		}
		geometry.addAttribute( 'color', new THREE.Float32BufferAttribute( colors, 3 ) );
	}
	var geometriesDrawn = [];
	var geometriesPicking = [];
	var matrix = new THREE.Matrix4();
	var quaternion = new THREE.Quaternion();
	var color = new THREE.Color();
	for ( var i = 0; i < 5000; i ++ ) {
		var geometry = new THREE.BoxBufferGeometry();
		var position = new THREE.Vector3();
		position.x = Math.random() * 10000 - 5000;
		position.y = Math.random() * 6000 -...