Watch this: Mind-blowing water simulation is now a reality

By Gergo Vas on April 23, 2013, 10:36 AM

Simulating the physics of water has always been tricky and game engines sometimes still have to use dodgy mechanics to make it feel real. But the above demonstration of this new fluid simulation technique proves that slowly but surely we're getting there.

PhysXInfo has the details how it works:

Position Based Fluids is a way of simulating liquids using Position Based Dynamics (PBD), the same framework that is utilized for cloth and deformables simulation in PhysX SDK.

Because PBD uses an iterative solver, it can maintain incompressibility more efficiently than traditional SPH fluid solvers. It also has an artificial pressure term which improves particle distribution and creates nice surface tension-like effects (note the filaments in the splashes). Finally, vorticity confinement is used to allow the user to inject energy back to the fluid.

According to PhysXInfo, it is running in real-time on a single GTX 580, which makes the whole thing even more impressive.

Republished with permission. Gergo Vas is an editor at Kotaku.




User Comments: 26

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LNCPapa LNCPapa said:

I can't wait for this to appear in games... and once fluids can actually change the behavior of other things in game (like making the floor slippery) it will be even better.

1 person liked this | NTAPRO NTAPRO said:

This would've been called witchcraft 10 years ago xD

The progress game physics have made over the years.

Blkfx1 Blkfx1 said:

This is amazing! Definitely something to look forward to.

Guest said:

Not realistic at all...

2 people like this | TomSEA TomSEA, TechSpot Chancellor, said:

That is EXTREMELY impressive. Fluids are the most difficult of all substances to graphically emulate due to its viscosity and ability to flow.

PinothyJ said:

The water physics in Hydrophobia Prophecy were pretty impressive...

2 people like this | VitalyT VitalyT said:

The question is - how much volume of water a modern graphical card can emulate this way?

Those shown in the demo were all small reservoirs. Many computer games like showing some sort of mountain rivers and big waterfalls in them for good natural impressions - how about that? I suspect it would be too much for a desktop graphical system to handle...

2 people like this | havok585 havok585 said:

Not realistic at all...

Where's the dislike button?

VitalyT VitalyT said:

Fluids are the most difficult of all substances to graphically emulate due to its viscosity and ability to flow.

Viscosity does not exist in this graphical emulation. Do not confuse it with the real physical emulation, that would be different. This one is just to provide realistic visuals. Viscosity emulation needs only to be used on macro level, when one or a few drops of water are emulated, but that's an entirely different emulation.

The ability to flow, as you called it, is much simpler than you may think, at least within a graphical emulation. It is down to miniaturized granules of the material emulating basic responses to gravitation + interactive forces in space-time, while maintaining constant state for structure+energy, I.e. granules are considered unchangeable, which is sufficient for a graphical emulation.

2 people like this | IvanAwfulitch IvanAwfulitch said:

Not realistic at all...

Where's the dislike button?

To be fair, there are a lot of other properties of fluid dynamics that this engine can't handle. Hydrogen bonding, water flow through pipes, larger bodies of water such as ponds, rivers, lakes, oceans, and additional physical properties at various temperatures...

The list goes on, but none of that is programmed into this demonstration. It's a very complex way of moving individual pixels around surfaces. Completely realistic? No. I can agree with that. But completely UNrealistic? No to that too. It is a dramatic step forward compared to water physics of the past. For how beautiful games have gotten, they still rely on tricks and tomfoolery to make you think it's water.

But we've grown wise to the tricks, and we have all been looking forward to an update on physics engines for just this sort of thing. There is a ton of work still to be done, and as VitalyT said, this kind of an advanced physics engine will wreak havoc on a graphics card. New drivers, graphics engines that incorporate these dynamics, directX solutions to work with the physics, and completely revolutionary graphics card hardware to perform break-neck speed calculations for it all... all of it needs a good amount of development before it becomes a realistic addition to game engines.

mrcavooter mrcavooter said:

I wish I had this on my Fluid Dynamics exam last quarter. Awesome progress!

VitalyT VitalyT said:

To be fair, ...

- I posted it first!

Cota Cota said:

The movement is a little slow like if it were saliva, and the momentum lacks resistance, but it looks real enough, btw what's the GPU load for this?, no point of getting exited if it tops the 580.

VitalyT VitalyT said:

The movement is a little slow like if it were saliva, and the momentum lacks resistance, but it looks real enough, btw what's the GPU load for this?, no point of getting exited if it tops the 580.

Oh-oh! How did I miss this one in my tangled logic. A PC game won't be able to emulate a character spitting (or worse ) at you, because this one would require a different emulation, one that does account for Viscosity + Capillary Action + DO Level (Dissolved Oxygen).

Yuk!

Talking of the real physical emulation, if I see 1 single drop of water simulated with those 3 parameters accounted for, I will be impressed!

NTAPRO NTAPRO said:

Must've taken a lot of math T_T

IAMTHESTIG said:

Yeah that was cool... now lets see a jet crash land on the water in BF4. The BF games still need a lot of improvement in the physics department. it's kind of sad seeing a tank bounce down rocks as if it only weighed 10,000 lbs and had springy suspension.

1 person liked this | VitalyT VitalyT said:

People seem thirsty for the Matrix era. In the meantime, check the nature outside - there is nothing wrong with that emulation, and it renders perfectly

1 person liked this | LNCPapa LNCPapa said:

My wallet is missing textures though

sapo joe said:

I liked it, but have seen already impressive water in the bioshock games, on the PC....

9Nails, TechSpot Paladin, said:

I like it. I like the whitewash, I like the way it looks fluid around the models. I'd like it more if it wetted the surface where the fluid touched. It is a nice particle effect, and I could see it as a fun addition to games if it doesn't tax the heck out of our GPU's.

But, more than fancy water I'm really wanting to see clothing on models however and not just stretchy skin-tight suits painted to the models but real clothing that moves with the model.

JC713 JC713 said:

This is awesome. Very impressed they could achieve this with current graphics technology. Nevertheless, I find nVidia's realtime ray tracing cooler:

http://www.youtube.com/watch?v=h5mRRElXy-w

But it is still years away .

St1ckM4n St1ckM4n said:

This news is old as dirt, no idea why Kotaku is reporting it now. The video uses GTX580, if that tells you anything.

Also, people seem to forget that this kind of full simulation is not required for most games. All we need is a small layer on top of oceans/lakes/rivers that is emulated.

Just Cause 2 on NVIDIA card. The best water I've ever seen in a game, period. I don't even know any other games which use the technology employed in JC2. It's simply amazing.

JC713 JC713 said:

The water in the BF4 trailer looked awesome. That didnt use any realtime physics I bet. Just tessellation if I am not mistaken.

TS-56336 TS-56336 said:

Impressive. Let's hope they use the tech to make a fun fluids-based game rather than for more realistic destruction physics in run-of-the-mill shooters.

JC713 JC713 said:

Impressive. Let's hope they use the tech? to make a fun fluids-based game rather than for more realistic destruction physics in run-of-the-mill shooters.

If what you mean by "fun fluid-based games" is similar to the 5 dollar games you see on steam, the development cost would be too high.

IvanAwfulitch IvanAwfulitch said:

- I posted it first!

And I credited you in my post!

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