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I noticed I reached a milestone number of postings today, 512 answers posted to the online Intro to 3D Graphics course. Admittedly, some are replies to questions such as “how is your voice so dull?” However, most of the questions are ones that I can chew into. For example, I enjoyed answering this one today, about how diffuse surfaces work. I then start to ramble on about area light sources and how they work, which I think is a really worthwhile way to think about radiance and what’s happening at a pixel. I also like this recent one, about z-fighting, as I talk about the giant headache (and a common solution) that occurs in ray tracing when two transparent materials touch each other.
So the takeaway is that if you ever want to ask me a question and I’m not replying to email, act like you’re a student, find a relevant lesson, and post a question there. Honestly, I’m thoroughly enjoying answering questions on these forums; I get to help people, and for the most part the questions are ones I can actually answer, which is always a nice feeling. Sometimes others will give even better answers and I get to learn something. So go ahead, find some dumb answer of mine and give a better one.
By the way, I finally annotated the syllabus for the class. Now it’s possible to cherry-pick lessons; in particularly, I mark all lessons that are specifically about three.js syntax and methodology if you already know graphics.
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.
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).
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.
Short version: the Interactive 3D Graphics course is now entirely out, the last five units have been added: Lights, Cameras, Texturing, Shader Programming, Animation. Massive (22K people registered so far), worldwide (around 128 countries, > 70% students from outside U.S.). Uses three.js atop WebGL. Start at any time, work at your own pace, only basic programming skills needed. Free.
That’s the elevator talk, Twitterized (well, maybe 3 tweets worth). I won’t blab on and on about it, just a few things.
First, it’s so cool to be able to show a student a video, then give a quiz, then let them interact with a demo, then have them write some code for an exercise, all in the browser. Udacity rocketh, both the web programmers and video editors.
Second, I’m very happy about how a whole bunch of lessons turned out. The tough part in all this is trying to not lose your audience. I think I push a bit hard at times, but some of my explanations I like a lot. Mipmapping, antialiasing, gamma correction – a number of the later lectures in particular felt quite good to me, and I thought things hung together well. Shhh, don’t tell me otherwise. Really, it’s not pride so much; I’m just happy to have figured out good ways to explain some things simply.
Third, I wrote a book, basically: it’s about 850 full-sized pages and about 145,000 words. It’s free to download, along with the videos and code. I think of this course as the precursor to Real-Time Rendering, sort of like “Star Wars: Episode 1″, except it’s good. I should really say “we wrote a book”: Gundega Dekena, Patrick Cozzi, Mauricio Vives, and near the end Branislav Ulicny (AlteredQualia) offered a huge amount of help in reviewing, catching various mistakes and suggesting numerous improvements. Many others kindly helped with video clips, interviews, permission to show demos, on and on it goes. Thanks all of you!
Fourth, I love that the demos from the course are online for anyone to point at and click on. Some of these demos are not absolutely fascinating, but each (once you know what you’re looking at) is handy in its own way for explaining some graphics phenomenon. The code’s all downloadable, so others can use them as a basis to make better ones. I’ve wanted this sort of thing for 16 years – took awhile to arrive, but now it’s finally here.
Fifth, working with students from around the world is wonderful! I love helping people on the forums with just a bit of effort on my end. Also, I just noticed a study group starting up. I’ve also enjoyed seeing contest entries, e.g., here are the drinking bird entries, click a pic to see it in WebGL:
What’s making a MOOC itself like? See John Owens’ excellent article - my experience is pretty much the same.
A close-up in the recording studio, my little world for a few weeks:
OK, this post is most definitely non-graphical, but I need to rant a bit.
While I wait for the last few elements of the MOOC I worked on to be released, I’ve been reading various opinions on MOOCs. Here’s the one theme that drives me crazy on a number of levels:
One of the dirty secrets about MOOCs — massive open online courses — is that they are not very effective, at least if you measure effectiveness in terms of completion rates.
That’s from a NY Times article, which is otherwise fairly positive. I’ve seen this opinion expressed a number of times elsewhere, and it’s meant as a serious critique or a dismissive gesture. From what I’ve read, it’s true that the completion rate is around 5% to 15%. However, it’s an apples to orangutans comparison to equate this with completion rates at colleges. Here are just a few obvious explanations.
The barrier to entry is low: “So, people who pay, or whose parents pay, $500 to $5000 per course are more likely to complete that course than those who pay $0? Shocking!” Say I have two computer programs I could use for a task. One costs $0, one costs $5000. I’ll certainly look at the $0 option first. If I paid $0, no big deal if I stop using the program. $5000, and I definitely am committed to use the program in a serious way, I want to get my money’s worth so I’ll make sure I need it and use it. But, really, this kind of misses the point. No one’s really weighing today’s MOOCs vs. traditional college curricula, for one obvious reason:
You’re getting just knowledge, not course credit or a QPA, nor even any parties: There’s a huge group of people ages 18-22 that go to college. They’re all there to get a degree, along with an education. Take away the degree aspect and most parents are not interested in plunking down the cash. Even alternatives such as Hampshire College produce an elaborate transcript for their students and some “proof of learning”. Take away the “meeting other students” aspect and that removes a significant aspect of the college experience for students: no dorms, no sports, no clubs, no parties, on and on. Comparing MOOCs with colleges is just silly. The main question that should be asked is “how do various MOOC techniques fit in with college education?” Flipped classrooms is the obvious one, and so how else can college education be improved? We don’t make every faculty member write their own textbook for each course they teach. What improvements can be gained by sharing more elaborate forms of media and interactivity for education? Articles such as this help.
Students who finish want to be there: That’s the dirty little secret of MOOCs. People are taking them because they want to, not because they have to. The main motivator is, “I want or need to know about this subject.” Since sign-up is free, there’s then all the things that will whittle down that number: “I was just curious what the course looked like” (there’s a huge percentage, maybe 40%, that never take a single class), “I thought it’d be fun, and it was at first, but then it got hard”, “I already knew most of the material”, “I learned the bits I wanted to know and never bothered to complete the course”, “the lecturer was boring/the course disorganized/the materials poorly presented/etc.”
I could go on, but I think you get the idea. The completion rate is a distraction and misses much of interest. It makes for an attention-grabbing fact but not much else. If you think about it, it would be downright bizarre if a free course open to all had a 90% completion rate. That would be the most amazing course ever, that it would be so compelling to almost everyone that signed up for it.
A MOOC can be thought about in another way. What if you told a professor, “every student taking your class is there because they want to be there, they want to know what you have to teach them”? That would be a dream come true. My humble course has 22K signups currently (many “name-brand” MIT, Stanford, and Harvard-backed online courses have over 100K students). Say just 1100 (5%) complete the course, and just 220 (1%) really loved the subject. 220 inspired students? I’ll take it! Heck, I’ll take 22. That may well be more truly inspired students than many teachers get a chance at in their careers. That’s a major reason many professors are excited by MOOCs and push to get their courses online through their universities. Getting messages from students such as, “in my country I think we don’t have schools making this kind of Course” is certainly fulfilling for me.
I like to give 7 links for a day, but I’ve been busy the past half year or so with the interactive 3D graphics MOOC. In two days the second half of the course will roll out, and I’ll blab about that later (in, like, two days). In the meantime, here are 490 links for the half year I’ve been missing. Basically, it’s the Instructor Notes for a bunch of the lessons in the course, additional material and links relevant to the subjects. I admit it, there are a lot of weaksauce links in there, basics for beginners and pointers to Wikipedia this and that. But there are also some great things in there.
Hey, let’s turn this into 7 great links (use Chrome or Firefox to view them, or enable WebGL in Safari):
- Why WebGL? - nice page (with a clever header) pointing out some of the best WebGL work out there. His math visualizations page is also cool.
- Mind-numbingly well-done and instructive terrain rendering demo in WebGL.
- Morph targets rigging for a face looks good in a browser.
- Using particles for model display gives an interesting look, with more data streaming in filling in gaps vs. the usual LOD popping.
- Some great slidesets on animation, collision detection, and other kinds of math from GDC 2012.
- To be honest, WebGL is a bit behind at this point, in DirectX terms being sort of Shader Model 2.0 to 3.0. But boy can that little dog dance: irradiance volumes, for example.
- Useful? Beats me, but it’s fun to watch Gource show the last year of development of three.js in two minutes. I like seeing myself flit in at the end and help shoot lasers at the source tree.
I know there are a bunch more links in the Instructor Notes that are worthwhile (things like the GLSL shader validator plug-in for Sublime Text 2), but these particular ones stuck with me.
I did get to visit the shrine one morning while in Mountain View recording:
OK, the obscure title can mean any of the following:
- We launched the Interactive 3D Graphics MOOC last Monday, and dinner follows l
- I’m feverishly working on the second half of the course (today I learned how to use tweening in three.js) and the only time I leave my office is for food and bed.
- This They Might Be Giants song is stuck in my head.
- Come and get it! It’s all downloadable.
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 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 RedBlobGames, AlgoViz.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.
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.
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.