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Cloth+Liquid=True

Started by MarcusLysen Aug 5, 2005 at 11:59 AM 13 replies 1.9k views
Original Post
MarcusLysen
MarcusLysen
I'm unfortunately not a frequent poster here but I thought that this forum might be the right place since I didn't want to make it into a news item. We have already linked to this from our site, so it's no secret anymore, so here goes: If you go here you can download some movies of cloth, rigid body and fluid interaction. It is based on a newer solver than the one we have available in the 1.5 version of the Meqon SDK and there is also an exe demonstrating some cloth/RB stuff. Oh, I almost forgot, there's a movie of some deforming metal and shattering as well. Best, Marcus /Edit: The movies are in DivX format [Edited by - MarcusLysen on August 6, 2005 1:35:44 PM]
LGAB
LGAB
Hallå där :)

I can't wait for all games to have completely destructable environments like that, it's great fun! I hope Duke-4-EverAndEver has some of this stuff in it :)
sbroumley
sbroumley
I can't get the movies to play - what media player codecs do I need?

cheers
Steve Broumley
MustEatYemen
MustEatYemen
Installed FFDSHOW and it played fine.
-Scott
LGAB
LGAB

Check out the real-time demo exe instead, it's dynamite :)
thebolt00
thebolt00
VLC reports the codec as DX50 so I guess it is DivX 5

-M
Timberl
Timberl
I love these animations, they're brilliant.

What are the sciences involved in them? I'd like to do some reading.

presumably rigid body kinematics for one...
mldaalder
mldaalder
I checked out the demo, it's fun.:P

But when I move those glass boxes with the dummy's in it, the box will move (or scatter) first, and when it stops the dummy will move.

Oh well, I suppose that will be fixed.
MarcusLysen
MarcusLysen
Oh, yes. The executable demo, or rather nothing on that page, is made with an official version of the engine and therefore not 100% reliable. However I hope it shows off the main simulation benefits anyhow. And what’s possible with an average PC already!

Also it might be worth mentioning that the movies were captured on a 2ghz system or so, a couple of years old dev machine anyhow.
MrRowl
MrRowl
Quote:
Original post by Anonymous Poster
Here is another nice simulation of fluids
http://www.continuousphysics.com/ftp/pub/test/index.php?dir=&file=Ageia_Airtight.mp4


Except there's a big difference - the Meqon video is a real-time capture running on old (existing) hardware. The Ageia video is, well, who knows what it is? There's no reason (that I know of) to think that most of the impressive stuff is real-time, and the bits of the videos that _are_ clearly from an interactive session have the physics running in slow motion (and there's one recent, similar, video that has terrible jitter too), even though it's the kind of stuff that could (just) be run in real-time in software! Novodex liquid running in software is _not_ interactive.

Incidently - I really like the Meqon fracture - very realistic looking. There are some issues with the demo (some jiggling on the ragdoll, jiggling, slowdown and not-sleeping when you pile up lots of tiles together etc) but generally it and the videos are pretty impressive, I think.
jovani
jovani
I always thought that Smoother Particle Hydrodynamics was a way of cheating the Navier equation of fluids, since it violates the more important characteristic of fluids which is incompressibility.
I have to admit that with good rendering techniques the method can be implemented to convey a very compelling fluids impression. Here is an implementation that is very nice too.

http://www.ss.iij4u.or.jp/~amada/fluid/

Since the method is so easy to implement and it fix rather nicelly with any existing solver techniques and even with ordinary particle systems, my guest is that each commercial engine (havoc and Novodex) will also come up with a more or less very polish implementation that will handle perhaps several thousand particles, specially using the extraordinary brute force power of these new consoles. I also think that the other free engines (True Axis, Newton, Tokamak and maybe even ODE) will follow suit with versions that won’t be as impressive since they do not have access to the new hardware, but with these new dual processors maybe they can do a decent job too.

The future of real time simulation will be very challenging, but that can only be a good thing.
MrRowl
MrRowl
Quote:
Original post by jovani
I always thought that Smoother Particle Hydrodynamics was a way of cheating the Navier equation of fluids, since it violates the more important characteristic of fluids which is incompressibility.


If I was being pedantic I'd point out that fluids aren't necessarily incompressible. Air is a fluid, for example. liquids are fluids that are at least nearly incompressible.

Also, you can add incompressibility (e.g. paper by Simon Premoze) to the equations using SPH - my understanding is that SPH is just a way of discretising the equations. However, doing so makes solving the system very slow because of the Poisson equation when you solve for pressure - just like grid methods.

One of the nice things about particle methods is that they conserve volume/mass (well, particles!), which is just as nice a thing as incompressibility, if not nicer - a container full of liquid that slowly evaporates due to numerical error isn't good :)
Airo
Airo
I like the fracture video. That looks like fun to play with.

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