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UCLA Adds Physics to Prat-falls 131

Posted by Hemos from the cheaper-then-people dept.
BaltoAaron writes "CNN.com is reporting on Petros Faloutsos , a UCLA scientist, that has developed a program that creates animation based almost solely on physics. Faloutsos "believes his animation program will one day allow virtual stunt artists to replace their flesh-and-blood counterparts in performing otherwise deadly feats of derring-do." "It's the Holy Grail of character animation. Everybody wants to do it, but there's not a whole lot of it out there right now.""
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UCLA Adds Physics to Prat-falls More

UCLA Adds Physics to Prat-falls

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  • Havent the video game makers created a program that creates animation based almost solely on physics yet? ;)

    • Re:Really? (Score:2, Funny)

      by Chiasmus_ ( 171285 )
      Havent the video game makers created a program that creates animation based almost solely on physics yet? ;)

      Sure, there's nothing I want more than to see a film where someone fires a gun at Keanu Reeves, and then he turns into a "Grand Theft Auto 3" style character made of polygons and falls to the ground with blood squirting out of his aorta.
    • Havent the video game makers created a program that creates animation based almost solely on physics yet? ;)

      Well, no, hence the reason you still need Marshall Fault to wear all those little bulbs while he runs around in tights.

      The article actually does a real good job comparing the two methods. Worth a read.

    • Re:Really? (Score:2, Informative)

      by Merlin42 ( 148225 )
      Kinda, but its always a pretty significant simplification. Only recently games have started adding things like Inverse Kinimatics(IK) in order to create motion sequences that are not just replays of motion capture.

      These days a game programming text looks like an abridged edition of a scientific modelling text.

      A big part of the trick is to have a realistic model of the human body. There are hundreds of joints of several varieties and many muscles controlled by the worlds most complex single entity(the brain). This makes it very hard to come up with a 'first principles' model. This is why most animation packages today (AFAIK) model the human body as a series of rigid parts(bones) connected by springs(muscles) with control points that the animator can use(the brain).

      Kevin
      • Is this really a new technology?

        I know that for the last 2 or 3 years, my school has had a program called Interactive Physics [interactivephysics.com]. While it seems like it may be a little more basic than this program, the concept seems to be the same.

        While I admit that I only have a little experience using it, from what I do know, using Interactive Physics, students can draw shapes on the screen, assign them physical properties, and then start the program and watch the animation that results.

        What is the big difference that causes this program to merit an article and posting of its own? The major difference that I see between the two programs is that Interactive Physics only supports 2D animations (to the best of my knowledge), while the program mentioned in the aticle supports three.

    • Re:Really? (Score:3, Interesting)

      by rhekman ( 231312 )
      No, not really. Game engine physics are purposefully incomplete for reasons of performance and gameplay.

      I seem to remember for example that normal character run speed in Unreal Tournament is over 30mph. They also tend to disregard inertia for enhanced control.

      Game engines could be modified for spatial realism. The Unreality Project for example. [unrealty.net] The problem is applying that technology for character models.

      Regards

  • This is lame by comparison (Score:3, Interesting)

    by Dan D. ( 10998 ) <duhprey@nOspaM.tosos.com> on Friday February 22, 2002 @07:07PM (#3054881) Homepage
    This guy http://www.q12.org/phd-movies.html did a physical body *and* made it walk with artificial controls. (And he's developed a library for the physics called ODE which makes doing a body falling down stairs about a days work, maybe half.)

    • Re:This is lame by comparison (Score:5, Informative)

      by Gary Yngve ( 416254 ) on Friday February 22, 2002 @07:44PM (#3055104)
      Sorry, but you are not very clued in on the
      research. Petros did not make a physical
      simulation of a human walking. That had been
      done many years earlier. Researchers at
      Georgia Tech [Hodgins, et al.] and U Penn
      [Badler, et al.] have focused on simulated
      humans since the early 90's, simulating motions
      from running to bicycling to diving.

      Petros's work was on integrating these motions
      together: so a character could walk, trip,
      dive, land, roll, and stand back up again.
      He used support vector machines to learn
      the domains of acceptable pre- and post-
      conditions of different movements and plan
      the transitions.

  • stick to plots rather than eye candy (Score:1, Insightful)

    by Anonymous Coward
    so, better special effects, big whoop
    • There are also many other applications for
      this and similar lines of research (including
      my current research):

      Education: Teach martial arts and use
      the system to visualize complex moves.

      Choreography: Rapidly prototype complex
      dance/gymnastics sequences realistially.

      Art: If this tool can be made intuitive
      for a novice user, character animation may
      finally become an accessible art medium
      for the masses.

  • Porn (Score:1, Insightful)

    by prizzznecious ( 551920 )
    What this guy meant to say is that this is the Holy Grail for Porn. You know why.

  • Not just normal physics, either (Score:3, Interesting)

    by texchanchan ( 471739 ) <ccrowley@@@gmail...com> on Friday February 22, 2002 @07:09PM (#3054896)
    You could get into the program and change a variable or two and have your characters looking like they really are on a high-gravity or low-gravity planet, or in the viscous atmosphere of Jupiter, or whatever you like! I'm looking forward to it.
    • It'd be neat to build artificial intelligence agents and let them loose in a "real" virtual world. We could test an agents response, and see how cool it could look, all at the same time!

    • You mean like NASA already did in 1969 with the "moon landing"?

      Now the minister of propaganda will be able to artificially render himself in front of an artificially rendered, fully clothed, sculpture, and show scenes from the latest battle in our war on the world.

      Seriously, I'm wondering what will happen on those fronts when we have the technology at hand to truly fool a viewing audience. At least right now I know that everything I see on TV is real!

      • Well if you look at the mutant flies story the other day, judging from the number of references to the three-eyed fish from The Simpsons being used as evidence as to what kind of DNA mutations can result from radiation exposure, it would appear that you need no technology more advanced than plain old cell animation. Some of the other people were not so easily fooled, it took the likes of Jurasic Park to fool them.

        As you can probably guess, my confidence in peoples ability to tell fact from fiction is very low. And we're not even talking about the computer illiterate types here.

        t.

    • You could also use computer stunt creatures that
      do not exist (aliens, dragons, an honest
      Enron exec) or perform motions that would be
      hard to convince humans/animals to do
      (pig & elephant going at it, a'la Southpark).
  • Except that it had been done using sensors placed on someone's body vs. coded. Sounds brilliant, though! I'd like to see some trash-and-smash on the big-screen that they haven't been able to do before.

    • Re:I thought this had been done already (Score:5, Insightful)

      by Chiasmus_ ( 171285 ) on Friday February 22, 2002 @07:29PM (#3055028) Journal
      Of course, there are definite advantages to putting sensors on someone's body.

      If I fall down the stairs, what's going to happen to, say, my right arm, wrist, and hand? Sure, if I'm unconscious, that will all be dictated by physics - I'll flop around like a rag doll and you can nicely see all the reactive forces at work.

      But if I'm conscious, how is the programming going to emulate my increasingly desperate attempts to keep from breaking my neck?

      It seems to me that a better effect would be captured simply by hooking up motion sensors to a stuntman, telling him to take a five-minute break, and then throwing him down the stairs when he wasn't looking. The "mechanics" realm of physics has relatively simple rules; panic does not. So far, we don't have any formulas for the interaction of perceived danger, temperament, adrenaline, and what have you.
  • Now we'll get to see the three stodges remade with Cowboy Neal, John Katz, and CmrdTaco punching each other using computer physics. What a great world.

  • saw it (Score:3, Interesting)

    by spookysuicide ( 560912 ) on Friday February 22, 2002 @07:12PM (#3054912) Homepage
    I saw a sneak of the time machine and I distinctly remember the skeleton crumbling scene they talk about in this article.

    I remember thinking that something about it looked unnatural, even a little cheap. Now I know it wasn't a low budget effect, just a new technique.

    While this may one day create much more realistic effect in film, I'm not sure it's quite ready yet. Did this scene stand out for anyone else that saw this flick as a little "off"?

  • Curious (Score:2, Insightful)

    by jweb ( 520801 )
    Haven't special effects wizards been using physics simulators for movie effects and video games for at least a few years now? Sure, this may be more advanced then previous physics engines, but is it really something revolutionary?

  • Maya (Score:1)

    by zaffir ( 546764 )
    I believe that Alias Wavefront's Maya has already done this.
    • Err not really. Maya has simulators for very specific circumstances. Every time a movie studio needs to come up with a new solution, something new has to be written in order to get the computer to do it. I think what this article is talking about is setting up a simulation so dynamic that nearly anything can be simulated, that's yet to be done today. The technology used to make a ball bounce is not the same technology used to make a skirt cling to Aki's body.
  • between this and the same hardware that can be used with lightwave or nomad?

  • Animate your own... (Score:5, Informative)

    by jsprat ( 442568 ) on Friday February 22, 2002 @07:16PM (#3054939)
    From his web page [ucla.edu]:

    DANCE is a portable, open, plug-in based, object-oriented software package for physics-based character animation. It runs on Linux, Irix, Windows 98/NT and is being ported to MacOS by Joe Laszlo. One of its goals is to provide researchers with a common platform where they can test their control methods and share their results. In addition, it provides the common, yet complex functionality that everyone needs in a physics-based animation system, allowing researchers to concentrate on their research work. Dance has been used for a variety of physics-based applications that include biomechanics modelling and composeable controllers. For more information, please contact the authors.

    It's available to download and play with!

    • It runs on Linux, Irix, Windows 98/NT and is being ported to MacOS by Joe Laszlo

      Is that the same Laszlo that lives in the steam tunnels?

    • In addition, it provides the common, yet complex functionality that
      everyone needs in a physics-based animation system

      Everyone needs this in a physics-based animation system? Oy vey! I don't even have a physics-based animation system! I'm doubly behind. I hadn't any idea I needed anything like this! Where can I get it, quick, before someone finds out?

  • finaly (Score:2, Insightful)

    by darklink ( 79588 )
    well if they can get the power to do it so be it.

    Every computer generted graphic movie thus far has failed but no one is totaly sure why. Final fantasy though excelent with the eye popping candy you realize that is is just a computer after 5 mins of enteraction. I dont see this comming to true fruition as of yet. But yes it would make for alot better FX. Some times i just watch a movie for the FX.

    The thing that worrys me most is that from most films eye candy takes up for true plot. Now if we can make a computer that can make really good plots the movies will rock.

    But this does sound alot better then bill hicks idea of using the termanaly ill and people sentanced to death to do this work. Though it still is kinda appealing.

    Kudos to any one that can pull it off am sure they will who knows one day we can all make gore fest as a plug in to adobe premere.

    • Re:finaly (Score:5, Informative)

      by FatRatBastard ( 7583 ) on Friday February 22, 2002 @07:21PM (#3054977) Homepage
      Every computer generted graphic movie thus far has failed

      Uh... Toy Story I/II, Bugs Life, Monster's Inc, Shrek, Antz (which I think sucked but did good business)... I wouldn't exactly call them failures.
      • I would like to qualify my statment about failure.

        They might have made a ton of money. You can still tell its fake. Alot of the movies are shooting for realizm. They have advanced computer generted characters but still you can pick them out of a crowd.

        More realizem would be nice, and this might translate into better manipulation into video game fields.

        • Then you need to leave "Final Fantasy" out of the mix. The creators specifically said, over and over again, that they *weren't* going for realism but more of a realism/anime cross.

          This they achieved admirably.

          Max
    • Every computer generted graphic movie thus far has failed but no one is totaly sure why. Final fantasy though excelent with the eye popping candy you realize that is is just a computer after 5 mins of enteraction.

      I think you're equating photo-realistic computer graphics with a successful film. The list quoted in the previous post [slashdot.org] by FatRatBastard shows that you can have one without the other. Also, implementing true physics in a film will not ensure photo-realism; I think that's more in the realm of optics, not physics.

      Now if we can make a computer that can make really good plots the movies will rock.

      Hell, I'll be happy if we can get a human to pull that off consistently :)

  • Good for him, but (Score:4, Informative)

    by epepke ( 462220 ) on Friday February 22, 2002 @07:17PM (#3054953)

    There has been research in this area being done for years, much of it presented at SIGGRAPH. There are techniques to animate characters through intricate plots just by specifying behavioral charactics, techniques to apply motion dynamics to characters of significantly different shape, and even "video puppetry" that allows images to self-animate in response to speech. All are a number of years old. All were hailed as holy grails. This just seems to be a case of CNN finally noticing.

    At last year's SIGGRAPH, everyone already knew about polynomial textures, because there had been a news story about it. To me, though, the highlight of the show was that it is now possible to walk around with an uncalibrated, handheld camera, and completely automatically get a decent 3-D model out of it (textured, of course). No news story about that.

    • I did some work on the 'ego motion' problem in grad school ie determining self-motion solely from an image sequence. Since this effectively the same problem as creating a 3D map from an image sequence, I'd be interested to see what the state of the art has evolved to. Any refs would be appreciated.

    • Sound too good to be true. (Score:3, Interesting)

      by eddy ( 18759 )

      To me, though, the highlight of the show was that it is now possible to walk around with an uncalibrated, handheld camera, and completely automatically get a decent 3-D model out of it (textured, of course).

      That sounds amazing. Does this mean that a formerly HARD AI problem (vision & representation) is now solved?! Do you recall any names or something, so that I can look for more information?

      • (A little quick on the trigger there maybe. To clarify; I do understand the difference between being able to create a 3d-world "as you go" (easier) from inferring it without being able to move about freely, and then going from (possibly erraneously inferred) 3d-data to "This is a chair" (harder), but the this sounds so much more advanced than the things I've read about in AI research (1990s stuff)). Pointers would be much appreciated.

      • No, it is not anywhere near solved. Funny
        that the MIT AI geniuses of the 50's expected
        vision to be solved in ten years. :) We still
        don't know how to take a bunch if pixels/voxels/polygons and determine that they
        are a toilet. Or even "easier" problems such as
        perfect segmentation or stereo-matching.

        Systems like the 10+ yard line in football
        aren't even perfect (what if shadows move or
        the sun/clouds do funky stuff or green uniforms interfere?). They have attendants present to
        correct quickly any errors.
        • >We still don't know how to take a bunch if pixels/voxels/polygons and determine that they are a toilet.

          Yes we do. But not if it's noisy, or it's a toilet we haven't programmed the system to recognize, or it's at an angle we left out of the set. Or you're sitting on it.

          Look up "radial logarithmic mapping".

          --Blair
      • Here [siggraph.org] is the course from the Siggraph 2001 Conference page. And here's the researcher's home page [kuleuven.ac.be]. Looks cool, way above my head though.
    • And you'd think CNN could at least post a link to the video or something, instead of just telling you it's really cool.
    • it is now possible to walk around with an uncalibrated, handheld camera, and completely automatically get a decent 3-D model out of it

      There are a lot of restrictions for scenes that can be modeled this way with current structure from motion algorithms. Occlusions usually cause severe problems, because the error model for the correspondence points does not take occlusions into account.

      Structure from motion is a low level method which operates with pixels, not objects. In order to deal with occlusions, higher level object models need to be integrated somehow into the system, but this is far from easy. I'd like to see any references of such systems.

  • Animats has done this for years... (Score:3, Informative)

    by Anonymous Coward on Friday February 22, 2002 @07:19PM (#3054965)

    Years and years...

    http://www.animats.com/

  • Ten years at SIGGRAPH (Score:5, Informative)

    by peter303 ( 12292 ) on Friday February 22, 2002 @07:19PM (#3054967)
    Physics-based animation has been a hot topic in computer graphics for a decade. SIGGRAPH made a major award to Prof. Andy Witkin of Carnige Mellon in 2001 for major progress in this field. This involves anmal motions, objects colliding, objects shattering (e.g. Phantom Menace) and so on.
  • That looks like way too much fun to toy with. That way I could say something along the lines of "I want to beat up my big sister", go through all the frustrating physics behind it... then not really want to do it as I would have exhausted my poor brian trying to figure out higher math. I think this is cool... good for the movie industry? Probably.. But eh, I also kinda like the actors that have the guts to do their own stunts. Shows they enjoy it and actually do the work they are getting paid to do. bad thing is, actors might be goin' out of work quicker.

  • SIGGRAPH (Score:2, Funny)

    by abramsh ( 102178 )
    Wow, all one-year-old SIGGRAPH papers should be slashdot stories.

  • Hells Bells (Score:3)

    by Starship Trooper ( 523907 ) on Friday February 22, 2002 @07:21PM (#3054981) Homepage Journal
    This is the death of competitive FPS games as we know it. No longer will we be able to change our jump direction in midair, jump 7 feet through windows, run tirelessly carrying 750 rounds of ammunition, and get hit by blast damage through walls.

    On the upside, the blood & guts is going to look a lot cooler.
    • That's a good thing. I think many people LIKE realism, i.e. CounterStrike. Imagine a game much along the same vein with this sort of physics. OTOH, in cs its more about guns guns guns, improved physics would only make the death animations more interesting; While in a fighting game it could significantly improve the gameply.
      • sorry, but, although Counter-Strike is a good game, it is far from realistic. The fact that people can stand on top of other people without problems, the fact that when climbing a ladder you dont put your gun away, etc. if they fix those things, it will be a much better game.
    • One claim is that once you have the accurate
      physics, you can tweak it and warp it to your
      satisfaction. An analogy could be that you
      cannot paint impressionistically if you
      cannot paint realistically.

  • This could be useful... (Score:5, Interesting)

    by ShooterNeo ( 555040 ) on Friday February 22, 2002 @07:21PM (#3054987)
    Well, the trouble with using it to replace stuntmen has as much to do with the realism of actual footage of an event vs a cgi simulation of one.

    That is, there are many other factors that cgi imagery comes no where close to mimicking, so even if tommorow this software let you create completely realistic human animation, it wouldn't put the union out of business yet.

    Many of the more spectacular stunts in our favorite action movies...such as the ones in crouching tiger...used the computer simply to composite the scene elements (like replacing the ropes from the flying harnesses), rather than recreate the scene. Or that train crash in Die Hard 3. The computer is often used to combine several "real" footages (like combining the actors on one set and the dangerous stuff on another) rather than do a whole scene, anyway.

    However, games could be great with this tech. I have always wanted to see a realistic fighting game, one with actual full physics animation, medical grade damage modeling (and when someone is hurt, realistic degradation of their performance), and the completely unscripted movements that an animation engine like this would allow.

    For instance, if someone punched your on screen avatar in the gut, your character would first stagger with the blow, and then shake back and forth as he tries to catch his breath. If you hit one of the attack commands at that moment, the subsequent attack animation would be modified by him still recovering from the blow, as WELL as what the other player was doing. A compltely freeform system. Yes, I know its possible to fake some of this now but there are some obvious limits. For instance, no matter how hard or how light your avatar got punched, he will probably still stagger with the same animation.

    And of course the "beowolf cluster" of all these technologies : a massively multiplayer online game where you can run around fighting other avatars like above, as well as casting spells, killing monsters, leveling, looting, camping, kill stealing... All the rest of the good things we come to expect from games of this type
    • Oh, and realistic "body physics" from scantily clad female fighters. That would sell more copies than anything. (especially if there were an unofficial "porno patch") Gotta love the power of smut.
    • Are you absolutely sure you want a fighting game that's realistic? Millions of people would complain about "play balance" in a realistic game. Face it, if you hit someone, physics dictates they're going down unless they take drastic measures to counteract that. And like you insinuated, if they take drastic measures, it leaves them open for more punishment. That's why, in real fights, it's almost always the guy who connects first that wins. And medical-grade damage modeling is definitely something you don't want. In almost every fighting game ever made, hitting someone in the stomach staggers them back, but that's about it. From (unfortunate) experience, getting hit in the stomach actuallymakes one double over and takes you out of the running for a minute or more.

      Let's face it...reality isn't fun. It takes a lot of money put from a special effects budget to make a movie look exciting. And that's because in real-life, things just aren't that cool.
      • The solution is to not be so anal about it. Make the forces on the avatar realistic but make the avatar super-human. By this I mean that if you punch him in the head, he goes down. However, it doesn't "hurt" him as much as it hurts a real person. Think about it, what we want is for games to look better not to be more realistic for realism's own sake.

        A good model to follow would be the kind of cartoon violence in movies like Die Hard, etc. Bruce gets hit with a lead pipe. He reacts with the full *force* of the impact (ie. he gets sent flying to the ground) but he gets up again - limping, with a bit of blood on him, but otherwise OK.

        When I shoot a rocket at someone in Quake, I expect them to react to the blast more than by just loosing health. They should be sent flying, or at least knocked over. Same goes for anyone close to them. So as not to affect game-play adversely, the blast radius could be kept unrealistically small (and fall off quickly) but within it I expect realistic reactions!

        If I shoot someone in the shoulder with a gun, they should react. They might do a quarter turn on impact, even though the amount taken from their health is the same.

        Remember what the goal for FPS is: fun violence. Make the game more realistic but don't go overboard at the expense of fun.

        • Someone please mod up this comment. The whole point of my original post was to make someone realize that maybe super-realism (which I was seeing advocated in a few posts) wasn't the most fun thing in the world. Obviously someone got it, but somehow it was my original "devil's advocate" post that got modded up.
    • However, games could be great with this tech. I have always wanted to see a realistic fighting game, one with actual full physics animation, medical grade damage modeling (and when someone is hurt, realistic degradation of their performance), and the completely unscripted movements that an animation engine like this would allow.
      Have you seen the Bioforge from Origin? It's an MS-DOS game for 486 with 8MB RAM and VGA, with "3-D, texture-mapped synthetic actors whose images actually show the injuries suffered in combat" (from the box) Not only the characters look hurt but they also behave accordingly, e.g. you fall down when you try to run, when you fight, etc. Of course today we have better graphics, but games as a whole are much less realistic than Bioforge was quite a few years ago on 20 times slower machines.
  • Now add this to some online games and suddenly Everquest becomes even more addictive.

    (Of course, knowing EQ, the requirements will go up to a Quad Xeon 2Ghz with 4GB RAM and dual GeForce 4's. And it will still be slow)
  • I think that there is something on it.
    Really!

  • http://www.mrl.nyu.edu/~dt/

    This is rather old, last year's SIGGRAPH and all, but I thought the even older artificial fish were always kinda cool.
  • There's nobody in the animation industry that thinks it's a good idea. Not directors, not animators, not modelers. The article talks about Character animation. Everything else has been out there for a long time. Particle simulations, rigid and soft body dynamics, and cloth sims are all standard in the industry now. But, and this is a big BUT, after the simulation is run there is ALWAYS tweaking that must be done by an artist. It might work for simple physics, but once again CNN is reporting 5 years too late.

  • Human brain still necessary. (Score:3, Insightful)

    by TekkonKinkreet ( 237518 ) on Friday February 22, 2002 @07:35PM (#3055069) Homepage
    I'm willing to believe that this is a new and sophisticated tool, though I see there are already a bunch of credible posts about prior art (I go to SIGGRAPH, too).

    My issue is that a lot more than physics needs to go into an animation. There's brain up there controlling all those muscles, it's not just a bunch of sticks and rubber bands. A character animator is an *actor*, part of his or her job is to give the appearance of intention to a character's performance.

    Falling down the stairs is (relatively) easy. Show me the panic the moment he realizes he's lost his balance and can't stop himself. Does he flop like a drunk or roll out like Jet Li?

    You still need to control a character with a human brain, whether that brain belongs to a mocapped stunt man or an animator.

  • CNN title misleading (Score:3, Informative)

    by Gary Yngve ( 416254 ) on Friday February 22, 2002 @07:37PM (#3055073)
    The researcher performed this work for his
    Ph.D. thesis at Toronto. Though he is
    most likely continuing the line of research
    as a professor, the article is about his
    thesis work.
  • "Inverse kinimatics" was added to such modeling/rendering programs as SoftImage [softimage.com] back in the early 90s. You could "drop" stuff and have it bounce around or blow in the wind or act like jello or whatever. Yes, even fall down stairs.

    You just create your model and connect the "bones" (fundimental objects that move) via articulated joints that could swivel in any direction you specify. Then determine what forces are acting on it (gravity or wind for example) and stuff like how the objects interact (do they bounce? or stick?) and then just hit "play" and off it goes...

    What's the big deal here?
    • When you use forces, as you suggest in
      the second paragraph, you are not doing
      forward/inverse kinematics, but rather
      forward/inverse dynamics, a much harder
      problem.

      And things like trees and jello behave
      passively, that is they don't produce any
      forces on their own from muscles, motors, etc.

      My guess is what you are referring to in the
      first paragraph is simple spring-mass systems.
      Modal analysis can be used to obtain more
      accurate deformations for things like trees.

      But if you want to simulate humans, you need
      to model the human's muscles as well if the
      human is anything but limp. The interaction
      can be very complex (especially given closed
      loop situations such as two legs on the ground).
    • Inverse Kinematics isn't a physics simulation, it's a method of moving bones around by connecting an end connector to a series of bones where the computer calculates the rotation of the bones based on where the end connector is. The old method is forward kinematics where the animator had to move each bone in the chain individually to get the hand or foot or whatever to wherever he/she wants it to be. So IK is far from connecting the bones, adding some forces and then hitting play and it's hardly a substitute for full fledged physics simulations of digital actors.
    • the inverse kinimatics (sic) stuff has been dealt with already. But i'd also like to mention that Dance has been available (through his site) for several years. Did you think this was banged out overnight?
    • IK is not phyics. You can't create a 'stunt' with IK without manually adding your own details to every little thing that happens.

      Frankly, I'm a little surprised that you know about features of Softimage, but you have trouble understanding how useful a 'real world physics simulator' would be. I have trouble beliving an animator would ever say 'what's the big deal?' to this type of goal.

      I would love to animate a crash landing in Lightwave where instead of keyframing every little thing, instead I set up a bunch of interesting areas to be affected by the crash. I'd like the results to surprise me instead of having to meticulously plan out every little thing that has to happen. I think that's what they mean by the stunt metaphor.

      Here's another example, what if a character opened a door and it caused the curtains in front of a window to billow for a moment as the pressure changed. To do that today, you'd have to animate the character opening the door, and *then* set up a totally seperate effect wher you place a 'wind generator' behind the curtain and tell it 'blow briefly for about a second on the same keyframe that the door opens.' The curtain would be a seperate object, and the 'wind' physics would only affect it. Nothing else in the room (unless specified) would react either. So a plant sitting on the dresser might sit unnecessarily still.

      It's that type of subtle interaction that it may not occur to an animator to create. Every little physical response like this in the 3D world adds a new layer of believability to the viewer. This makes animation more immersive, and more rewarding to do because the user gets sucked into the world that the animator has created.

      Try turning on your imagination a little bit and you might just find what the big deal is, instead of saying 'I already have that if I just jump through a few dozen extra hoops.' It's an attitude I've seen aspiring animators have over the years, but it takes them a while to discover that saying "so what?" is also saying "I don't feel like growing today."
  • in watching Jackie Chan movies :-)

    Jackie Chan rocks!
  • Every decent visual effects house is already doing better stuff than that - and with physics too.

  • The foot (Score:4, Funny)

    by Dolly_Llama ( 267016 ) on Friday February 22, 2002 @08:29PM (#3055280) Homepage
    "It's the Holy Grail of character animation."

    I thought Terry Gilliam was the Holy Grail of anima.. oh nevermind..

  • Since when have movies cared about physics? I mean, in Speed the bus "jumps" an unfinished section of an overpass.

    And when was the last time you saw a movie where the explosion is seen BEFORE it is heard?

    Not to mention virtually every space fiction movie ever made with the sole exception of 2001.
    • Hey he's right! I saw an episode of Beavis and Butthead once and Butthead threw a pair of dice and they landed without even bouncing once! Ever since that day, animation never reached a higher respect of physics!

      Sarcasm aside, the movie industry cares very much about physics. They may exaggerate them from time to time (like the jumping bus, heh), but they pay very careful attention to it when they are doing animated movies. Take Snow White, for example, they had a scene with lots of people dancing in it. They actually filmed a bunch of dancers and rotoscoped them, using their motions to make the characters move in the movie. The result? A surprising level of realism in that scene.

      Hollywood cares more about physics than your limited over-simplification indicates.
  • this post should be taken with a grain of salt, as I am not a professional 3-D computer animator. however, I am trained in the art/craft of 2-d animation (particularly drawn character-based animation), so I'm far from clueless.

    simply put, physics based animation will have a _long_ distance to go before it starts to look "good" to anyone who wants to see anything beyond "physics".

    The inherent problem is that there is rarely a one-to-one correspondence between something being "physically accurate" and something being "visually entertaining". in other words, entertaining/compelling visuals aren't necessarily based in physical reality.

    Prime anecdotal evidence: Wile E. Coyote.

    "But that's not live action!" you say. Well, this also applies to the vast majority of live-action "action movie" sequences; the overwhelming majority of these are composed of multiple takes shot from multiple angles on multiple sets, and later composited/edited together - in other words, the action was _not_physically_possible_, but had to be "assembled" from lots of smaller, quasi-physically-possible elements.

    many of the posts here reference video game physics as unrealistic; they've got it exactly right - except that this is far more than a video-game-specific issue.

    of course, in the long term the need to "ficitionalize/cheat" at physics may be addressed by a layer operating _above_ the physics engine (perhaps tweaking physical laws, running a simulation but changing the rules over time, etc.), but in the end it's still going to take a lot of direct creative input in order to get anything out of these systems that anyone will _want_ to see.

    and it will be an even longer time before the output from that kind of system will produce anything not directly comparable to graphic work entirely based on photoshop (or GIMP) "filters" - i.e. it will look pre-packaged, cheap, and not terribly distinctive.

    while I really appreciate the work that these people are doing (and believe that it will have wonderful applicatons in court cases/medicine/sports), calling physics-based animation a "holy grail" for _storytelling_ is nothing other than to mistake the long term goal of these projects as being to completely remove humans from the creative process of filmmaking.

    and I've already seen "Battlefield Earth", thank you.

    - jdbo

  • Saw his demo last month (Score:3, Informative)

    by mbrubeck ( 73587 ) on Friday February 22, 2002 @09:32PM (#3055528) Homepage
    Dr. Faloutsos gave a colloquium talk to the CS department at my college [hmc.edu] recently, including a dozen or so simple examples of his DANCE system. It was really very impressive.

    Faloutsos' work is not actually focused on the physics models, but on the control programs for the virtual actors. This allows dynamic, force-based animation (as opposed to kinematic, position-based animation). Each model has a set of controllers for various tasks like walking, running, jumping forward, moving from a prone position to a standing position, etc. Each controller knows its "competencies" -- the conditions under which it can successfully guide the model. These are used to hand off control from one controller to the next as the model goes through a complex motion or reacts to external forces.

    The sample movies that Faloutsos showed were mostly unscripted. They would start with a model in a simple standing state, which would then respond to user-controlled forces like pushing or throwing simulated balls at the model from various angles. Various balance-recovery controllers would take over depending on how the model was displaced; if none of them were succesful then the model would fall down, and then use one of its controllers for returning to a standing position. All of this appeared incredibly realistic and human.

    Also, as another poster noted, DANCE [ucla.edu] is available under a "free for non-commercial use" license (not free under the FSF or Debian definitions, but a good deal in my opinion). He encouraged us to try it out, explaining that research like his has suffered from a lack of common infrastructure, leading to a lot of reinvented wheels. He expressed hope that the DANCE framework would allow more innovative research with less duplicated work.

  • Everybody knows that the Road Runner cartoons are based almost entirely on quantum physics.
  • ...how much better Jar Jar Binks would be.

  • My zero-point energy extraction device. I've waited for this moment for years.
  • Am I the only one who wanted to be the unknown stuntman growing up? Crap, there goes another career option.
  • http://www.cs.ucla.edu/~pfal/animations.html
  • I think it'd be fun to play with a physics simulator of sorts, but to be honest, I'd rather have a tool where I can change or even invent my own laws of physics. Take Yosemite Sam for a moment: somehow he can survive a shotgun blast in the butt. In reality, his butt'd be missing a few important pieces, but in Toon Town, the unexpected happens.

    Physics are.. well.. expected. If I could change the rules around a bit, I could create fun yet silly little movies. Remember that Far Side cartoon where a black hole suddenly formed in that guy's apartment, and everything started getting sucked into it? Heh I could animate that! Let me tweak the physics a bit, and I could really have some fun with it!
  • maybe it's just late, or maybe I'm pissed about being mistaken for gay one time too many, or maybe my feminism is rearing its head, but this quote is strinking me as being especially retarded:
    "You can tell from how someone is walking if they're effeminate or angry. How would you account for that in a physics-based system?" said Darren Hendler, technical director at Digital Domain Inc., a Los Angeles special effects studio.
    "effeminate or angry"? Guess he hasn't met too many pissed-off women.
  • Physics game engines will be creating the next level of gaming experience. For the past few years there have been tremendous advances in the realm of graphics, rendering objects in amazing detail and complexity. However, those verisimilar badboys are merely eye-candy that glosses over a scripted world.

    With the introduction of physics modeling, your victim can die a thousand different deaths, and remove that deja-vue feeling you get after killing the thousandth Strogg.

    While many games have incorporated aspects of physical modeling into their games, I believe this stuff is finally about to pop. I know that the Sony PS2 was built on MathEngine's physics SDK, and Seamus Blackley (one of the pioneers of the genre and developer of Trespasser, the first game to incorporate physics into most aspects of gameplay - and was a flop) has been hoisted by Microsoft for the Xbox developement. Maybe soon we'll stop getting that feeling everytime we lock and load that someone is whispering in our ear to "ignore the man behind the curtain!"

    Related links:
    (2001) http://www.wired.com/wired/archive/9.08/physics.ht ml
    (1999) http://zdnet.com.com/2100-11-514530.html

    Physics Engine players:
    http://www.mathengine.com
    http://www.ha vok.com

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