Udacity

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The recently and sadly departed Game Developer magazine had a great post-mortem article format of “5 things that went right/went wrong” with some videogame, by its creators. I thought I’d try one myself for the MOOC “Interactive 3D Graphics” that I helped develop. I promise my next posts will not be about MOOCs, really. The payoff, not to be missed, is the demo at the end – click that picture below if you want to skip the words part and want dessert now.

Good Points

Three.js: This layer on top of WebGL meant I could initially hide details critical to WebGL but overwhelming for beginners, such as shader programming. The massive number of additional resources and libraries available were a huge help: there’s a keyframing library, a collision detection library, a post-processing library, on and on. Documentation: often lacking; stability: sketchy – interfaces change from release to release; usefulness: incredible – it saved me tons of time, and the course wouldn’t have gone a third as far as it did if I used just vanilla WebGL.

Web Stuff: I didn’t have to handle any of the web programming, and I’m still astounded at how much was possible, thanks to Gundega Dekena (the assistant instructor) and the rest of the Udacity web programmers. Being able to show a video, then let a student try out a demo, then ask him or her a question, then provide a programming exercise, all in a near-seamless flow, is stunning to me. Going into this course we didn’t know this system was going to work at all; a year later WebGL is now more stable and accepted, e.g., Internet Explorer is now finally going to support it. The bits that seem peripheral to the course matter a lot: Udacity’s forum is nicely integrated, with students’ postings about particular lessons directly linked from those pages. It’s lovely having a website that lets students download all videos (YouTube is slow or banned in various places), scripts, and code used in the course.

Course Format: Video has some advantages over text. The simple ability to point at things in a figure while talking through them is a huge benefit. Letting the student try out some graphics algorithm and get a sense of what it does is fantastic. Once he or she has some intuition as to what’s going on, we can then dig into details. I wanted to get stuff students could sensibly control (triangles, materials) on the screen early on.  Most graphics books and courses focus on dreary transforms and matrices early on. I was able to put off these “eat your green beans” lessons until nearly halfway through the course, as three.js gave enough support that the small bits of code relating to lights and cameras could be ignored for a time. Before transforms, students learned a bit about materials, a topic I think is more immediately engaging.

Reviewers and Contributors: I had lots of help from Autodesk co-workers, of course. Outside of that, every person I asked “can I show your cool demo in a lesson?” said yes – I love the graphics community. Most critical of all, I had great reviewers who caught a bunch of problems and contributed some excellent ideas and revisions. Particular kudos to Gundega Dekena, Mauricio Vives, Patrick Cozzi, and at the end, Branislav Ulicny (AlteredQualia). I owe them each like a house or something.

Creative Control: I’m happy with how most of the lessons came out. I overreached with a few lessons (“Frames” comes to mind), and a few lines I delivered in some videos make me groan when I hear them. However, the content itself of many of the recordings are the best I’ve ever explained some topics, definite improvements on Real-Time Rendering. That book is good, but is not meant as an introductory text. I think of this course as the prequel to that volume, sort of like the Star Wars prequels, only good. The scripts for all the lessons add up to about 850 full-sized sheets of paper, about 145,000 words. It’s a book, and I’m happy with it overall.

Some Bad Points

Automatic Grading: A huge boon on one level, since grading individual projects would have been a never-ending treadmill for us humans. Quick stats: the course has well over 30,000 enrollments, with about 1500 people active in any given week, 71% outside the U.S. But, it meant that some of the fun of computer graphics – making cool projects such as Rube Goldberg devices or little games or you name it – couldn’t really be part of the core course. We made up for this to some extent by creating contests for students. Some entries from the first contest are quite nice. Some from the second are just plain cool. But, the contests are over now, with no new ones on the horizon. My consolation is that anyone who is self-motivated enough to work their way through this course is probably going to go off and do interesting things anyway, not just say, “Computer graphics, check, now I know that – on to basket weaving” (though I guess that’s fine, too).

Difficulty in Debugging: The cool thing about JavaScript is that you can debug simple programs in the browser, e.g. in Chrome just hit F12. The bad news is that this debugger doesn’t work well with the in-browser code development system Udacity made. The workarounds are to perform JSHint on any code in the browser, which catches simple typos, and to provide the course code on Github; developing the code locally on your machine means you can use the debugger. Still, a fully in-browser solution with debugging available would have been better.

Videos: Some people like Salman Khan can give a lecture and draw at the same time, in a single take. That’s not my skill set, and thankfully the video editors did a lot to clean up my recordings and fix mistakes as found. However, a few bugs still slipped through or were difficult to correct without me re-recording the lesson. We point these out in the Instructor Notes, but re-recording is a lot of time and effort on all our parts, and involves cross-country travel for me. Text or code is easy to fix and rearrange, videos are not. I expect this limitation is something our kids will someday laugh or scratch their heads about. As far as the format itself goes, it seems like a pain to me to watch a video and later scrub through it to find some code bit needed in an upcoming exercise. I think it’s important to have the PDF scripts of the videos available to students, though I suspect most students don’t use them or even know about them. I believe students cope by having two browser windows open side-by-side, one with the paused video, one with the exercise they’re working on.

Out of Time: Towards the end of the course some of the lessons become (relatively) long lectures and are less interactive; I’m looking at you, Unit 8. This happened mostly because I was running out of time – it was quicker for me to just talk than to think up interesting questions or program up worthwhile exercises. Also, the nature of the material was more general, less feature-oriented, which made for more traditional lectures that were tougher to simply quiz about. Still, having a deadline focused my efforts (even if I did miss the deadline by a month or so), and it’s good there was a deadline, otherwise I’d endlessly fiddle with improving bits of the course. I think my presentation style improved overall as the lessons go on; the flip side is that the earlier lessons are rougher in some ways, which may have put students off. Looking back on the first unit, I see a bunch of things I’d love to redo. I’d make more in-browser demos, for starters – at the beginning I didn’t realize that was even possible.

Hollow Halls: MOOCs can be divided into two types by how they’re offered. One approach is self-paced, such as this MOOC. The other has a limited duration, often mirroring a real-world class’s progression. The self-paced approach has a bunch of obvious advantages for students: no waiting to start, take it at your own speed, skip over lessons you don’t care about, etc. The advantages of a launched course are community and a deadline. On the forum you’re all at the same lesson and so study groups form and discussions take place. Community and a fixed pace can help motivate students to stick it through until the end (though of course can lose other students entirely, who can then never finish). The other downside of self-pacing is that, for the instructor(s), the course is always-on, there’s no break! I’m pretty responsible and like answering forum posts, but it’s about a half hour out of my day, every day, and the time piles up if I’m on vacation for a week. Looking this morning, there are nine forum posts to check out… gotta go!

But it all works out, I’m a little freaked out. For some reason that song went through my head a lot while recording, and gave a title to this post.

Below is one of the contest entries for the course. Click on the image to run the demo; more about the project on the Udacity forums. You may need to refresh to get things in sync. A more reliable solution is to pick another song, which almost always causes syncing to occur. See other winners here, and the chess game is also one I enjoyed.

Musical Turk

 

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OK, the obscure title can mean any of the following:

After a few months of writing lessons, I’m entirely in the mode of “how can I make a question or exercise out of this lesson?”

As of yesterday I think of the course as “outta beta”. There are some minor glitches we’ll fix in the weeks ahead, but now all the major stuff is in place. The thing that’s entirely great is that everything about the course is downloadable (thank you, Udacity). All the videos, for example, which is a big help to people with slow or censored YouTube connections. Here’s the rundown:

  • Videos are available in unit-sized chunks.
  • Code is all githubbed here, and there’s a zip download. Unzip and run the index and they’re all there (except solutions).
  • All my lesson scripts are here, and there’s other good stuff on the wiki page there. Tallied up, the first half of the course, in five PDFs, comes out to 367 letter-sized pages (admittedly a lot of figures, but that’s A Good Thing). Jeez, I’m writing a book. With code. And videos.
  • I put the demos (and exercises, but not solutions) up here. Click and you’re running a demo. This is just the github distribution uploaded to our site. I’ll make a guide to all the demos once the course is done; some of these are pretty handy for explaining things, once you know what you’re looking at.
  • All lesson instructor comments are here. Some lessons have additional information and links to resources. Rather than have to search through all the lessons for that link you saw somewhere, they’re all here.

Entirely unrelated, but here’s the cool three.js link for the day.

I heart procedural modeling, I don’t heart Apple’s driver bug that makes it so WebGL can’t use antialiasing.

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I spent a few minutes last week skimming through my unread stack of “Communications of the ACM” (CACM) – they were piling up. I enjoy the lighter articles for the most part, especially those on copyright and patent issues. The more serious articles would probably do me good to read, but no time, no time.

One bit that caught my eye: “Will MOOCs Destroy Academia?” A MOOC is a massive open online course, e.g., I’m working on one (I think there were about 15,000 sign-ups for it as of last month). I’d summarize the article as: “college courses where the professor lectures to all are ineffectual and costs are soaring [his words, not mine], but MOOCs are popular only because they’re free, and a Cambridge don says universities are critical to civilization”. His concluding sentence was particularly surprising to me: “If I had my wish, I would wave a wand and make MOOCs disappear, but I am afraid that we have let the genie [out] of the bottle.” The word “out” is in the on-line HTML and PDF versions, but not in the original print magazine. I guess the internet is good for something, though clearly not education, by the author’s estimation.

The author, by the way, is the Editor-in-Chief of CACM; I sometimes disagree with his views, but usually appreciate that some thought has been put into his opinion pieces. This time the research appears to have been the book “What Are Universities For?” and the Bible. I was cheered to see some reasonable replies.

For a CACM article with much more chew and nuance, see “Reflections on Stanford’s MOOCs“. This article is worth your time if you’re interested in a survey of various combinations of education and the internet for teaching computer science.

Me, I’m happy to see it’s possible to teach (in any form) using three.js on top of WebGL – click a link and you’re taken to a demo, or code you can edit and run in the browser. Try it now, if you want: for three.js demos, go to the three.js page and click on any appealing thumbnail (caveats being “use Chrome” or “enable on Safari” – see this worthwhile page if you have problems). For code in the browser, try here or any of these. For WebGL demos, some of which are wonderful, see webgl.com. And there are great things out there beyond these, I’ll cover more here once I have the time. A few days back Steve Worley pointed out this amazing thing, a classic tile terrain renderer, all in a web page.

This all couldn’t have been done at all two years ago – WebGL was officially released on March 3, 2011. This is great news for anyone teaching graphics, either online or in the classroom (or both).

Becoming a computer graphics programmer is something I consider as much an apprenticeship as a set of college courses. That’s how I felt as I began to be one at Cornell back in 1983-85. The Masters program in the Program of Computer Graphics was officially one 18 credit course each semester (and summer), along with “take a minor”. It was essentially “live and breathe graphics” for two-plus years. Teenagers in the demoscene have similar experiences, I expect.

I ran across a great quote from Confucius, which I’ll probably use at the end of the MOOC, “Every truth has four corners: as a teacher I give you one corner, and it is for you to find the other three.” This fits my view of computer graphics: you can be given a foundation in the subject, but it’s mostly up to you to learn by doing and pursuing knowledge (Confucius probably meant something entirely different). The fact that you can now do this on your own with a PC and enough self-motivation and online support I find wonderful (take the creator of three.js, for example).

Going to a college or university and learning from a good teacher and working with other students is fantastic stuff; I consider myself fortunate to have been able to do so. There are great professors and programs out there. Even humble basic courses (such as mine) are a boon, as they can expose and motivate some students to get involved and find their passion. However, the field of computer graphics (unlike, say, genetics, where you can’t currently buy a DNA sequencer for $25, but can buy a GPU for that) is quite accessible even if you can’t commit to being a full-time student.

So, back to doing my little bit to help destroy universities because, you know, that’s just the kind of guy I am. Honestly, I think MOOCs have their place, and my own vision of the future is one where professors can grab chapters, videos, githubbed code and so on to supplement their courses, and they can make their own creations available to others. They can say “take this MOOC over the summer and come back in the fall ready to go,” so that everyone has a baseline understanding.

Committing nowadays to a single textbook, for example, seems archaic. Few people have the time to write a whole book, so there are only so many to choose from and each has chapters a teacher will not use, either for time or for dislike of the author’s approach. However, plenty of people can write a short article explaining mipmaps or scaling matrices or other topics, and a few of them will be superb. Sites with educational content such as RedBlobGamesAlgoViz.org, and Online Python Tutor are signs of how things can be (BTW, I learned of those URLs from the useful CACM article). Mixing and matching among these resources allows engaging and powerful new tools for teachers and students.

Behold your doom, universities

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Launched!

As of today, March 11th 2013, the free online interactive 3D graphics course I’ve been working on has begun, at last. I’ve been laboring in earnest and more than full time on this class since October (thank you, Autodesk), and I’m just the most visible person on the project. There’s a raft of others at Udacity making things work and look great: web programmers, video editors, and particularly Gundega Dekena, the assistant instructor on the course. Many other people inside and out of Autodesk have been contributing time for interviews, for video clips, and  for reviewing material (special shout-out to Patrick Cozzi and Mauricio Vives for reading over everything). It’s way more total work creating a video course than writing a book, maybe equivalent to the effort of making a movie vs. writing a novel.

Some of the slick things Udacity has done is integrate video lessons, WebGL/three.js demos, and exercises and questions all in a continuous series. I’d point at an URL, but you do have to sign up for the course to see its structure. Also, wait a day or so: by tomorrow a bunch more links to resources should be in place, at least for Unit 1. Soon the course code will be githubbed, the videos all downloadable, etc. (update: this is now done.)

By the way, this is only the first half of the course. I’m in the throes of writing the second half, which will come out May 1st. I’m learning the video creation process as I go, so I think the quality is increasing as the units progress. Gesturing at the screen and reading what I wrote at the same time gives me a new-found respect for weathermen.

Even if you already know about 3D graphics, you might want to check out the history of the teapot video, which Martin Newell kindly fact-checked. And if you don’t know who Martin Newell is, or only know that he created the teapot model, then you definitely should watch the video. Oh, and then try the WebGL/three.js demo here.

What’s nice is that all the course videos are hosted on YouTube, so it’s easy for anyone to link to any of the lessons (well, except where YouTube is blocked; Udacity has  alternate delivery methods). I hope that these videos and demos will be handy for other people explaining 3D graphics.

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I’ve been more than a bit busy working on the (newly renamed) Interactive 3D Graphics course for Udacity, so have been tardy pointing out that this cool course is out now: Introduction to Parallel Programming. Taught by John Owens, David Luebke, and others, it uses CUDA as its basis for teaching. I look forward to taking it myself! It’s a free online course with some serious content, graded exercises, and much else to recommend it – a lot of time & effort (& money) was put into making it, so I expect it will be worth my while.

Oh, and I should also mention another new course, HTML5 Game Development, from experts at Google. It’s more 2D graphics related, but again looks like quite a serious course with a lot of chew.

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