Three.js анимирование объектов сцены
 

Доброго времени всем. Дали задание - есть чертёж фундамента из AutoCAD и необходимо сделать типо обучающего ресурса. Я конвертировал составляющие этого фундамента в формат .dae(collada). Долго бился над тем, как же в петле анимации сделать так, чтобы анимация(drop - объекты падают сверху) была для каждого объекта отдельно. Вроде бы получилось, но я уверен это не из лучших решений... Подскажите как улучшить следующий код(желательно чтобы были краткие примеры кода, чтобы по ним я мог ехать дальше...)
P.S. Заранее спасибо
Собственно сам код:

//container for render
var container;

//scene elements
var camera, scene, renderer, controls;

//downloaded items
var objects = new Object();

//load manager
var manager;

//widnow size
var SCREEN_WIDTH = window.innerWidth - document.getElementById('panel').offsetWidth;
var SCREEN_HEIGHT = window.innerHeight;

//list of files
var filename = [	'axes_1.dae',
									'prepare_2.dae',
									'base_3.dae',
									'joint_4.dae',
									'dump_course_5.dae',
									'fbs_6.dae',
									'joint_fbs_7.dae',
									'joint_fbs_gor_8.dae',
									'fbs_9.dae',
									'joint_fbs_9.dae',
									'joint_fbs_gor_10.dae',
									'fbs_11.dae',
									'joint_fbs_12.dae',
									'joint_fbs_gor_13.dae',
									'fbs_14.dae',
									'joint_fbs_15.dae',
									'air_course_16.dae',
									'air_course_17.dae', ];

//path to files
var path = 'stages/stage/';

// for animate objects
var count = 0;
var offset = 100;
var step = 5;

init();
load_models();

//function init() {...}


function animate() {

	requestAnimationFrame(animate);
	controls.update();

	render();

}

function render() {
	if (selected !== null) {
		switch (selected.id) {
		case '1':
		if (count === 0) drop(objects['axes_1.dae'].children);
		if (count === 1) drop(objects['prepare_2.dae'].children);
		if (count === 2) selected = null;
		break;
		case '2': 
		if (count === 0) drop(objects['base_3.dae'].children);
		if (count === 1) drop(objects['joint_4.dae'].children);
		if (count === 2) selected = null;
		break;
		case '3':
		if (count === 0) drop(objects['dump_course_5.dae'].children);
		if (count === 1) selected = null;
		break;
		case '4': 
		if (count === 0) drop(objects['fbs_6.dae'].children);
		if (count === 1) drop(objects['joint_fbs_7.dae'].children);
		if (count === 2) drop(objects['joint_fbs_gor_8.dae'].children);
		if (count === 3) selected = null;
		break;
		case '5':
		if (count === 0) drop(objects['fbs_9.dae'].children);
		if (count === 1) drop(objects['joint_fbs_9.dae'].children);
		if (count === 2) drop(objects['joint_fbs_gor_10.dae'].children);
		if (count === 3) selected = null;
		break;
		case '6':
		if (count === 0) drop(objects['fbs_11.dae'].children);
		if (count === 1) drop(objects['joint_fbs_12.dae'].children);
		if (count === 2) selected = null;
		break;
		case '7': 
		if (count === 0) drop(objects['joint_fbs_gor_13.dae'].children);
		if (count === 1) selected = null;
		break;
		case '8':
		if (count === 0) drop(objects['fbs_14.dae'].children);
		if (count === 1) drop(objects['joint_fbs_15.dae'].children);		
		if (count === 2) selected = null;
		break;
		case '9':
		if (count === 0) drop(objects['air_course_16.dae'].children);
		if (count === 1) selected = null;
		break;
		case '10':
		if (count === 0) drop(objects['air_course_17.dae'].children);
		if (count === 1) selected = null;
		break;
		}
	}
	renderer.render(scene, camera);

}

//function onWindowResize() {...}

function load_models() {

	manager = new THREE.LoadingManager();

	manager.onProgress = function (item, loaded, total) {
		console.log(item, loaded, total);
	}

	manager.onLoad = function () {
		console.log('all items loaded');

		animate(); //start animate
	}

	manager.onError = function() {
		console.log('there has been an onError');
	}

	filename.forEach( function (filename) {

		var loader = new THREE.ColladaLoader(manager);
		loader.load(path + filename, function (collada) {

			var dae = collada.scene
			dae.scale.z = dae.scale.x = dae.scale.y = 1;

			dae.traverse( function (child) {

				if (child instanceof THREE.Mesh) {

					child.material = new THREE.MeshNormalMaterial();
					child.material = new THREE.MeshLambertMaterial( {emissive: 0x111111, color:0x111111} );
					child.material.transparent = true;
					child.material.opacity = 1;
					child.material.side = THREE.DoubleSide;

				}

			});
			
			objects[filename] = dae;
		 	scene.add(dae);

		});
	});

}




var select = function (div) {

	if (selected !== null) {
		selected.className = 'scene';
	}

	selected = div;
	selected.className = 'scene selected'

	allVisible(false);

	switch (selected.id) {
		case '1':
		count = 0;
		setPosition(objects[filename[0]].children);
		setPosition(objects[filename[1]].children);
		break;
		case '2':
		count = 0;
		setPosition(objects[filename[2]].children);
		setPosition(objects[filename[3]].children);
		for (var i = 0; i < 2; i++) objects[filename[i]].visible = true;
		break;
		case '3':
		count = 0;
		setPosition(objects[filename[4]].children);
		for (var i = 0; i < 4; i++) objects[filename[i]].visible = true;
		break;
		case '4':
		count = 0;
		setPosition(objects[filename[5]].children);
		setPosition(objects[filename[6]].children);
		setPosition(objects[filename[7]].children);
		for (var i = 0; i < 5; i++) objects[filename[i]].visible = true;
		break;
		case '5':
		count = 0;
		setPosition(objects[filename[8]].children);
		setPosition(objects[filename[9]].children);
		setPosition(objects[filename[10]].children);
		for (var i = 0; i < 8; i++) objects[filename[i]].visible = true;
		break;
		case '6':
		count = 0;
		setPosition(objects[filename[11]].children);
		setPosition(objects[filename[12]].children);
		for (var i = 0; i < 11; i++) objects[filename[i]].visible = true;
		break;
		case '7':
		count = 0;
		setPosition(objects[filename[13]].children);
		for (var i = 0; i < 13; i++) objects[filename[i]].visible = true;
		break;
		case '8':
		count = 0;
		setPosition(objects[filename[14]].children);
		setPosition(objects[filename[15]].children);
		for (var i = 0; i < 14; i++) objects[filename[i]].visible = true;
		break;
		case '9':
		count = 0;
		setPosition(objects[filename[16]].children);
		for (var i = 0; i < 16; i++) objects[filename[i]].visible = true;
		break;
		case '10':
		count = 0;
		setPosition(objects[filename[17]].children);
		for (var i = 0; i < 17; i++) objects[filename[i]].visible = true;
		break;
	}

	
}


function allVisible(visible) {

	filename.forEach( function (name) {
		objects[name].visible = visible;
		objects[name].children.forEach( function (item) {
			item.transparent = true;
			item.material.opacity = 1;
		});
	});

}



function setPosition (object) {

	for (var i = 0; i < object.length; i++) {

		object[i].position.z = offset;

		object[i].material.transparent = true;
		object[i].material.opacity = 0;

	}

}

	function drop(object) {

		for (var i = 0; i < object.length; i++) {

			if (i == 0 && object[i].position.z > 0) {
				
				object[i].parent.visible = true;
				object[i].material.opacity += 0.5;
				object[i].position.z -= step;

				if (object[i].position.z < step) object[i].position.z = 0;

				break;

			}

			if (i > 0 && i < object.length - 3 && object[i].position.z > 0) {

				object[i].parent.visible = true;
				object[i].material.opacity += 0.5;
				object[i].position.z -= step;
				object[i+1].position.z -= step / 1.5;
				object[i+2].position.z -= step / 2.25;
				object[i+3].position.z -= step / 3;

				if (object[i].position.z < step) object[i].position.z = 0;

				break;
			}

			if (i > object.length - 4 && object[i].position.z > 0) {
				
				switch (i) {

					case (object.length - 3):

						object[i].parent.visible = true;
						object[i].material.opacity += 0.5;
						object[i].position.z -= step;
						object[i+1].position.z -= step / 1.5;
						object[i+2].position.z -= step / 2.25;

						if (object[i].position.z < step) object[i].position.z = 0;

						break;


					case (object.length - 2):

						object[i].parent.visible = true;
						object[i].material.opacity += 0.5;
						object[i].position.z -= step;
						object[i+1].position.z -= step / 1.5;

						if (object[i].position.z < step) object[i].position.z = 0;

						break;


					case (object.length - 1):

						object[i].parent.visible = true;
						object[i].material.opacity += 0.5;
						object[i].position.z -= step;

						if (object[i].position.z < step) {

							object[i].position.z = 0;

							count++; //animation finished. next animation

						}

						break;

				}

			}

		}

	}