Motion Capturing in Three Dimensions?

brokenbeaker asks: "I friend of mine is a modern dancer, and she is working with a 3D modelling program to record dance performances. Apparently, the system is very primitive - if you make a dancer jump, she doesn't fall back down to earth. My question is, does anyone know of a sophisticated (physics based, I guess) modelling program that can be used to record dance? How about motion capture in 3D - would this be feasible? Anyone looking for a programming challenge?"

Recording?

[caca_phony]

The things you talk about seem to have more to do with composing dance than recording it...
The formal composition of dance is a field that is hardly developed, most of dance is mixtures of repartorie learned one on one through generations with no formal theory or notation behind it. That means you're not gonna have very good luck finding any computerized tools for dance composition, AFAICT.

What about the motion trackers used for animation?

[Slashamatic]

One of the techniques used in computer assisted animation is to film an actor wearing a dark costume with strategically placed reflective dots. Cameras feed images through for processing which allow the animation process to be made more realistic (i.e, no cartoon physics). The raw output of the system is an articulated stick figure which goes to animate the 3d character.

I guess as this is the movie industry, such stuff would not be cheap and probably require a beowolf cluster or two to run it.

Re:

[account_deleted]

Comment removed based on user account deletion

software?

[tolldog]

What software is she using?

I know that Maya has a pretty complex modeler and it has solvers that allow for all sorts of stuff.
You can do IK solvers for a body and you can also add influences to states, such as gravity and wind.

I created a simple marble toy using the system. It would drop a marble and launch another one off of a see-saw and then start rolling down a track.

If she really wanted realism, she should look into motion capture, as other have suggested. It doesn't really take that complicated of mocap setup. Just patience and time at the end to tweak the animation keys.

-Tim

Good Luck

[Aix]

It is difficult to appreciate just how difficult this problem is. In terms of Artificial Intelligence, we don't even really have the technology for stereoscopic vision yet, much less three dimensional modeling from visual input. For video games and movies, I believe the state of the art is to strap a bunch of specially-colored objects all over the person's body and put them in extremely bright light, then try to reconstruct the body's kinematics from the movements seen in various cameras around the room.

Otherwise, I would do a search for "visual hulls". You'll get some inforfmation about trying to define surfaces given multiple pictures of the same object. Still a difficult problem - getting correlated points is the hard part.

In any case, good luck - you'll need it.

Vicon

[inkfox]

For motion capture, you might suggest she look at Vicon [vicon.com], the most popular motion capture system. Plan to have a couple hundred thousand bucks set aside for an entry-level system though. (Ouch.)

For hand-editing, the character animation software in Maya may be a good place to start. Or, look at any of the "bipedal toolkits" for other 3D animation packages. There are packages designed specifically for facilitating hand-animation of humanoid figures. Still, you're talking several grand and a relatively beefy computer for this.

I believe that AnimationMaster [hash.com] has basic support for this stuff as well, and it can be had as cheaply as $299. Possibly worth some extra investigation there.

Hmmm. This has been in use for a while. U of C.

[muonzoo]

Although I cannot find a specific-cool link at their site, the Human Performance Lab [ucalgary.ca] in the Department of Kinesthetics [ucalgary.ca] has been doing some mightly cool motion capture and analysis of atheletes, normal people and people with physical limitations for years. Very cool Sun based motion tracking system. My climbing partner in Uni used to be the technician for the capture / analysis systems. They were SPARC systems at the time, from sun [sun.com].
As other posters have mentioned, motion capture and motion synthesis tend to be very different problems, although in an end product (if it is a rendering) may contain elements of both.
Alias' [sgi.com] tools still tend to be some of the better products out there for synthesis. If you are serious about capture, I know that the U of C department would at least be a starting place for software sources. I know that it wasn't an inexpensive setup.

Lifeforms from Credo

[iamiuru]

I used this program for a while, it has been some time though; but it was pretty good at exactly what you are looking for. You can import various 3d files and it will export the timeline to many 3d apps.

You can check it out here [charactermotion.com]. Found an article off of google about them now giving you a free 30 day full trial version - so at least you can check it out and see.

As I recall there were a bunch of pre built dance moves in there for choreographers - much easier to start with something then to make everything from scratch. I could keep going on about this but it's just much better to go to there site and see all the features.

Hope this will be helpful. Unless of course this was the program that she was already using.

Re:Lifeforms from Credo

[darkonc]

Lifeforms seemed to do pretty much what you're asking for when I last saw it (in 1993!). If it's been getting support since then (which seems to be the case), then it should be pretty nice, by now).

NUDES

[gfim]

There was a package developed by Don Herbison-Evans at the Univesity of Sydney (Australia) some time ago called NUDES that did exactly this. Have a look at Dance and the Computer: A Potential for Graphic Synergy [uts.edu.au].

Try a Google search for "nudes" "dance" "software" "university".

Graham