3D graphics in the browser have been a hot topic since they were introduced. But if you were to create your apps using plain old WebGL it would take ages. That’s why some really useful libraries have come about. Three.js is one of the most popular of them, and in this series I will show you how to make the best use of it to create stunning 3D experiences for your users.

I expect you to have a basic understanding of 3D space before you start reading this tutorial, as I won’t be explaining topics like coordinates and vectors.

Preparation

As usual, we will start from the code that you created earlier. Download and unpack the assets I provided and you’ll be ready to go.

Step 1: A Word About Exporting Models in Blender

Before we start the programming part, I will explain something that many people have problems with. When you have a model created in Blender, and you want to export it to Three.js format, you should keep the following in mind:

• First, remove the parenting. The Three.js exporter won’t export any animations if you leave it (this also applies to the Armature Modifier)
• Second, group vertices. If you want the bone to move any vertices you have to group them, and name the group with the name of the bone.
• Third, you can have only one animation. This may sound like a big problem, but I will explain the workaround later.

Also, when exporting you have to make sure that these options are selected in the exporter: Skinning, Bones and Skeletal Animation.

Step 2: Importing the Model

As with pretty much everything in Three.js, importing models is very simple. There is a special class, THREE.JSONLoader that will do everything for us. Of course it only loads JSON models, but it’s recommended to use them so I will only cover this loader (others work pretty much the same way). Let’s initialize it first:

var loader = new THREE.JSONLoader;
    var animation;
    

No arguments needed. We also need to define a variable for animation, so we can access it later. Now we can load the model:

loader.load('./model.js', function (geometry, materials) {
    	var skinnedMesh = new THREE.SkinnedMesh(geometry, new THREE.MeshFaceMaterial(materials));
    	skinnedMesh.position.y = 50;
    	skinnedMesh.scale.set(15, 15, 15);
    	scene.add(skinnedMesh);
    	
    	animate(skinnedMesh);
    });
    

The load method accepts two parameters: a path to the model and a callback function. This function will be called when the model is loaded (so in the meantime you can display a loading bar to the user). A callback function will be called with two parameters: the geometry of the model and its materials (these are exported with it). In the callback, we are creating the mesh—but this time it’s THREE.SkinnedMesh, which supports animations.

Next, we move the model 50 units up to put it on the top of our cube, scale it 15 times (because I tend to create small models in Blender) and add it to the scene. Next we call the animate function that will set up and play the animation.

Step 3: Animation

Now we set up the animation. This is the source for the animate function:

function animate(skinnedMesh) {
    	var materials = skinnedMesh.material.materials;
    
    	for (var k in materials) {
    		materials[k].skinning = true;
    	}
    
    	THREE.AnimationHandler.add(skinnedMesh.geometry.animation);
    	animation = new THREE.Animation(skinnedMesh, "ArmatureAction", THREE.AnimationHandler.CATMULLROM);
    	animation.play();
    }
    

First we have to enable skinning (animations) in all materials of the model. Next, we have to add the animation from model to THREE.AnimationHandler and create the THREE.Animation object. The parameters are in the following order: the mesh to animate, the animation name in the model and interpolation type (useful when you have a complicated model like a human body, where you want the mesh to bend smoothly). Finally, we play the animation.

But if you open the browser now, you would see that the model is not moving:

To fix this, we have to add one line to our render function, just below the particleSystem rotation:

if (animation) animation.update(delta);
    

This will update the time on the animation, so THREE.AnimationHandler knows which frame to render. Now open the browser and you should see the top cube bend to the left and to the right:

Step 4: Multiple Animations

Yes, there is a workaround for only a one animation sequence in a model, but it requires you to edit it. The idea is that you add each animation to one sequence, then, when that one ends, the next one begins. Next, after you’ve exported your model, you need to change the animation code. Let’s say we have a standing animation from the beginning to the third second, and a walking animation from the third second to the end. Then in our render function we have to check on which second the animation is, and if it reaches the end time of the current sequence, stop it and play it from beginning:

var currentSequence = 'standing';
    
    function (render) {
    ...
    	if (animation) animation.update(delta);
    	if (currentSequence == 'standing') {
    		if (animation.currentTime > 4) {
    			animation.stop();
    			animation.play(false, 0); // play the animation not looped, from 0s
    		}
    	} else if (currentSequence == 'walking') {
    		if (animation.currentTime <= 4 || animation.currentTime > 8) {
    			animation.stop();
    			animation.play(false, 4); // play the animation not looped, from 4s
    		}
    	}
    ...
    }
    

You have to remember to start the animations not looped and from the correct time. This will of course be buggy if the user’s frame-rate is really low, because the delta will be higher and animation.currentTime may be much higher than the limit for any particular sequence, resulting in playing some part of the next sequence. But it will be noticeable only if deltas are about 300-500ms.

Now to change the animate function to play the walking animation, just add these arguments to the animation.play function:

animation.play(false, 0);
    

Also, let’s allow the user to switch between animations using the a key. Add this code at the end of the file, just before the render() call:

document.addEventListener('keyup', function (e) {
    	if (e.keyCode == 'A'.charCodeAt(0)) {
    		currentSequence = (currentSequence == 'standing' ? 'walking': 'standing');
    	}
    });
    

Step 5: Attach to Bone

This technique is particularly useful in RPGs, but it can apply to other genres as well. It involves attaching another object to the bone of the animated object: clothes, weaponry, etc.

Let’s start by modifying our loader.load callback. Add this code under the scene.add(skinnedMesh'):

item = new THREE.Mesh(new THREE.CubeGeometry(100, 10, 10), new THREE.MeshBasicMaterial({ color: 0xff0000 }));
    item.position.x = 50;
    pivot = new THREE.Object3D();
    pivot.scale.set(0.15, 0.15, 0.15);
    pivot.add(item);
    pivot.useQuaternion = true;
    skinnedMesh.add(pivot);
    

The item mesh simulates something you may want to attach to an animated object. To make it rotate around a specific point, and not around the center, we will add it to a pivot object and move it 50 units (half of the width) to the right. We have to scale it to 0.15, because it will be added to the skinnedMesh that has a scale of 15. Finally, before it’s added to our animated object we tell it to use quaternions.

Basically, quaternions are a number system, but since Three.js handles everything for us, you don’t have to delve into this topic if you don’t want to (but if you do, take a look at its Wikipedia page). They are used to rotate objects without the risk of gimbal lock.

Now, in the render function we have to update the object’s position and rotation:

pivot.position = new THREE.Vector3().getPositionFromMatrix(skinnedMesh.bones[2].skinMatrix);
    pivot.quaternion.setFromRotationMatrix(skinnedMesh.bones[2].skinMatrix);
    

Let me explain what is happening here. First, we set the position to be the same as on the last bone in the model. We are using the skinMatrix property to calculate it. Then we use the same property to calculate the quaternion for the pivot‘s rotation. After that, you can open the browser and you should see the red beam attached to our model:

Conclusion

I hope you’ve learned a few new interesting techniques from this tutorial. As always, feel free to experiment with the app that we’ve created. In the next (and last) tutorial in this series, I’ll show you the true power of OpenGL/WebGL—Shaders.

Christopher Corbett, professor of the practice of English, recently reviewed a new book for The Wall Street Journal about Red Cloud, a Sioux war chief who defeated the U.S. Army and negotiated unprecedented concessions from the government. In “The Heart of Everything That Is: The Untold Story of Red Cloud, An American Legend,” authors Bob Drury and Tom Clavin tell the story of the powerful and successful Indian warrior.

“The great Sioux war chief, a military genius of the Indian wars, is a largely forgotten figure in the shape-shifting history of the American West,” Corbett wrote. “In his day, he presided over a vast swath of the continental U.S.—from Canada to Kansas and from what is today Minnesota and Iowa to Idaho and Utah. His name was much-feared.”

“‘The Heart of Everything That Is’ is a vivid if melancholy story that may make readers ponder our relationship with the memory of the American West,” Corbett added.

Corbett is the author of “Orphans Preferred: The Twisted Truth and Lasting Legend of the Pony Express” and “The Poker Bride: The First Chinese in the Wild West.”

You can read the full book review in The Wall Street Journal here (subscription required).

• Presents information on Asian Americans and individual Asian ethnic groups that provides comprehensive overviews of the respective groups
• Includes special topic entries that contain source information regarding major historical events
• Comprises work from a truly outstanding list of contributors that include scholars, journalists, writers, community activists, graduate students, and other specialists
• Expands the boundaries of Asian American studies through innovative entries that address transnationalism, gender and sexuality, and inter- and cross-disciplinarity

• Alien Land Laws
• Asian American Gay and Lesbian Movement
• Asian Americans and Affirmative Action
• Asian Americans in Hollywood
• Asian Indian Women in America
• The Chinese Confession Program
• Chinese Railroad Workers in America
• Japanese American Transnational Families
• Korean Cuisine in America
• Multiracial Asian American Families
• Multiracial Coalition after the Los Angeles Civil Unrest of 1992
• Native Hawaiians and Pacific Islanders
• Parachute Kids
• Ronald Takaki
• The Yellow Brotherhood

Hampton Catlin is widely known for being the creator of Sass and Haml. He’s also the author of “The Pragmatic Guide to Sass,” built the mobile version of Wikipedia, Dictionary! for iPhone, and founded the libsass project.

I recently interviewed Hampton while producing Sass Basics, our new course on Sass. In the interview he talks about how he got into web development, why he created Sass, the importance of open source projects and more!

The Interview:

How did you get into web development?

I picked it up mostly by myself. A friend of mine had a ‘zine in high school called “The Van” and so I worked my way through some ASP book to get something simple working. I had no idea what I was doing. A year later, I built a site called “Sorry, Cow” that was basically a simple app where you could sign your name to an irony-laced apology letter addressed to all the cows that we eat, and will still continue eating. It poked fun at both vegetarians and meat eaters. It ended up getting several hundred thousand signatures and was a big hit on LiveJournal with badges. It totally blew my mind that something I could make in my room would cause people to smile all over the world. Hundreds of thousands of people. That kind of impact just isn’t conceivable with any other medium.

You developed Sass back in 2006, what exactly was it about CSS that made you feel like you needed a better solution for writing CSS?

Nesting. Easy answer for me. I just couldn’t believe the amount of repetition that was required to style things *correctly*. We were expected to repeat ourselves if we wanted any decent scoping and I hated that it was harder to do the right thing. That’s a lot of how I think about products I’m working on… thinking about what should be easy and what should be hard. Product design isn’t always about making things easier, sometimes it’s about making bad behaviours really difficult.

CSS is evolving faster than ever. Do you think CSS will ever catch up with Sass, or at least be able to do some of the things Sass does?

I don’t think CSS should do most of the things Sass does. The only one it should support natively is nesting. Why nothing else? Because, I think we make our browsers do too much thinking these days. Have you ever thought about all the JS loading on every page load across the internet? jQuery is compiled millions of times a second on CPU’s everywhere… and mostly it’s unused. If that button is supposed to be red, then we can know that before you show up on the page. No reason to make every users’ browser repeat the same calculation! Some things are great for developers and some things are great for machines. Sass is for developers.

How important is it these days to work on––or contribute to––open source projects?

It’s an absolute necessity. One of the core traits that is important to me is collectivism. It’s the attribute that people actually care about other people. If I have an issue, then I want to fix it for others. Open source really helps you flex that muscle and get better at it. It teaches you how hard it is to get into a new project, and it also shows you how rewarding helping can be. At Moovweb, I push my teams to contribute back to the community as much as possible. We make it a pretty formalized part of day to day development.

Do you think it’s better to have a portfolio site, or a Github profile with several projects?

Depends on which direction you want to take your career. Portfolio sites are great if you are on the more creative end, but if you want to become a full time backend developer, great code samples are very important. I like to have both, myself. But, it all depends on how you want to brand yourself and what kind of role you are looking for.

You’re super passionate about delivering amazing mobile experiences. What are some of the biggest challenges you still face with mobile design and development?

The number one challenge to building great mobile web experiences is the insane amount of JavaScript bloat that exists on the Internet today. The culture of “just add it in!” has gone a bit far. It’s common for us to see sites with megabytes and megabytes of barely-used Javascript. I’d say the number two challenge is the total lack of solid UI design on Android devices… it looks like the early web! Embarrassing.

Beside Sass, Haml, and Moovweb, you’ve worked on a lot of mobile games and apps. How do you manage your time and all projects?

I work on a fully fluid system. If something interests me, I pursue it. If my interest wanes, I drop it. I am a person who thrives in chaos! For every successful project I’ve launched, I have hundreds of ideas that are half baked. I believe that the only time you know if something will work is by starting to work on it. The process of having to build and design is also the process of revealing the secrets of the project. I don’t believe in knowing beforehand if something will work or not. You just have to take the first step, then re-evaluate. And, more times than not, that re-evaluation means I move on to something different. But yeah, I don’t manage my time, I just let myself do what I feel.

Where do you see Sass and Haml in the next few years?

Probably living together in a cottage in Upstate New York, watching the seasons change, making jams. Reading each other french poetry and discussing the latest episode of Miss Marple. Or… Sass is poised to continue changing how we perceive front end design.

Many of your creations came about because you felt there were important problems that needed solutions. If you’d never sought out solutions, some of these problems would likely still persist today. How important is it for designers and developers to take on solving problems themselves––like you did with Sass and Haml––and not just wait for someone else to do it?

Finding what makes you passionate is the most important step. If you aren’t into big ideas, don’t punish yourself because you aren’t doing wilder things. Figure out who you are and how you want to value your own life story. Write the biography you want for yourself.

For me, it’s always been about finding ways to push technology and progress forward while building better and better things for the world. I get such a kick out of that kind of impact. It probably comes from my childhood love of the Carousel of Progress at Walt Disney World. I wanted nothing more than to invent something that might appear in the ride! I’ve always wanted to be a real participant in the insane rocket ride that is human progress and invention. Where are we going? I have no idea, but we’re going there fast and I can’t wait to find out!

The post An Interview with Hampton Catlin appeared first on Treehouse Blog.

The logic of carpooling is simple: it reduces the costs for all parties involved and takes at least one car off the road. If other students are coming from the same area and heading to UMBC around the same time, carpooling may be an easy way to meet other UMBC campus members, reduce UMBC’s carbon footprint, and save money as well as a number of other benefits.

Creating a carpool with UMBC students is easy—join the online “Casual Carpooling” forum just for UMBC members and discuss the details of a carpool (http://my.umbc.edu/groups/casualcarpooling).  The Casual Carpooling myUMBC group now has over 400 UMBC members! For an enjoyable and safe ride, we posted some suggestions and tips such as “carpool etiquette” on the webpage.

Face-to-face socials are also hosted by the office of Off-Campus Student Services throughout the year. The next carpool social is on February 14, 2014 with a Valentine’s Day theme at Lower Flat Tuesdays in The Commons from 12-1PM.

The REU in Microbiology at The University of Iowa seeks to foster the careers of the next generation of microbiologists. We do this by providing an intensive 10-week research experience for bright and ambitious undergraduates who are considering a PhD in microbiology or an allied discipline. We hope that this experience will encourage students to pursue a career in basic science and give them the skills they need to succeed in that career path. The focus of the program is a hands-on research project conducted under the guidance of faculty and graduate student mentors. A range of research projects will be available, including basic mechanisms of bacterial and viral gene expression, virus structure and assembly, biofilm formation, microbial development, and prokaryotic cell biology. Students will also attend lectures to broaden their understanding of microbiology and educate them about graduate school and career options. 

Overview of the Program

• Participants conduct full-time, hands-on research in microbiology, microbial genetics, or molecular biology.
• An overview of research programs in our department can be found by clicking here, and a list of recent summer REU projects can be found here.
• Enrichment activities include weekly seminars and workshops on graduate school and career opportunities. Schedules from past years: 2009, 2010, 2011, 2012, 2013.
• At the end of the summer students present their findings in a campus-wide poster session.
• Program lasts for 10 weeks (May 27-August 1, 2014).
• Participants receive a $5,000 stipend plus a $515 food allowance.
• On-campus housing is provided at no cost to the participants.
• Travel costs are paid by the program.

Eligibility

The program is intended for undergraduates who:

• Have completed at least two years of college.
• Will be returning for at least one semester of undergraduate study before graduation.
• Are majoring in a biological science.
• Are interested in pursuing graduate school and a career in biological research.
• Are United States citizens or permanent residents (hold a green card).
• Have limited access to research opportunities at their home institution.
• Prior research experience is NOT a requirement.

REU- Nanotechnology for Biology and Engineering