Nvidia’s PhysX has finally cracked realistic, real-time rendered water
By James Plafke on April 24, 2013 at 11:28 am
Our graphics capabilities have sort of plateaued as of late. Games and movies look better than they ever have, but we’re still embroiled in an eternal battle with the Uncanny Valley. No matter how great a video game heroine’s hair looks, or how many individual furs are articulated on an anthropomorphic Pixar character, we can still instantly tell that computer-generated graphics are just that — generated by a computer. Aside from human eyes and mouths, one of the biggest enemies of the Uncanny Valley is computer-generated water. With PhysX’s position based fluids, though, CG water flows the best we’ve ever seen.
Perhaps the closest we’ve come to mind-blowing computer-generated water effects in a consumer product is the water in the Uncharted series. The way the water flows won’t explode any brains, but how it dampens anything it touches, exactly where it touches, is nothing short of mesmerizing. For instance, whatever angle a character enters a body of water, his or her shirt and pants will become damp based on which parts of the clothing actually touched the water. While that realism is impressive, it certainly doesn’t translate to the way the water flows. However, PhysX’s position based fluids research seems to have produced computer-generated water that moves just like the real thing.
CG water that behaves similarly to real fluid has been around for a while — most notably in tech demos showing off that it’s possible, or perhaps appearing in the occasional big-budget movie. However, it’s too computationally intensive to put into a real-time application, like a video game. For as pretty as the CryEngine is, our hardware just can’t dedicate enough resources to generate fancy flowing fluids. Now, though, Nvidia’s Miles Macklin and Matthias Müller-Fischer have figured out a way to reduce the load on hardware, generating a result that is remarkably fluid, but “suitable for real-time applications.”
Position based fluids — the method used — is similar to the one that dictates the behavior of computer-generated cloth, position based dynamics. Unfortunately, the exact methods used to reduce the computational load and create lifelike water movements haven’t yet been revealed, as Macklin and Müller-Fischer are saving the details for a forthcoming research paper. What the pair did note, though, is that they were able to create surface tension, improve particle distribution, and lower the overall computational requirements to get everything working.
The “real-time applications” weren’t defined, and we’re not sure if that means consumer-grade entertainment media, or expensive and powerful systems used by professional designers. The above video is a mightily impressive tech demo either way. The water bounces and flows like it would in real life, shimmying between cracks, rolling off of curved surfaces, and adhering to inertia. Almost benevolently, the video morphs the water into little spheres, giving us something of an X-ray view of how the water moves.
Hopefully, the PhysX duo will be able to transfer the position based fluids method to next-gen consumer-grade applications, and we’ll soon be able to watch water soak a character’s shirt, but realistically bounce around between his arms and off of his torso during the process.
Check out the demo video in that article, impressive!!