Cryostasis To Use PhysX For Fluid Simulation

Ever since NVIDIA acquired AGEIA and assimilated their PhysX IP, there has been an outcry for more triple-A game titles that fully utilize the technology. Currently there are only a handful of popular, shipping titles that take full advantage of PhysX, but NVIDIA's developer relations team seems to have been pushing hard and the company has been able to make a number of interesting announcement regarding PhysX support in some highly anticipated, upcoming games. We've already shown you the NVIDIA GPU PhysX packs that consists of a number of patches, updates, tech demos, and even some full games that support PhysX, and have posted a video of PhysX in action in EA DICE's hot upcoming title Mirror's Edge. And today we can show you some footage from another PhysX-enabled title, 1C's Cryostasis, that actually uses PhysX in a way that no other PC game has before.

According to NVIDIA and 1C, Cryostasis is a first person, survival-horror shooter due to be released in early 2009. The game is set in a dark environment where ice is constantly melting, making water a key theme in the game. Because water is such a key element, and 1C wanted it to look as realistic as possible, Cryostasis is the first game to use the GPU to calculate fluid simulation using smoothed particle hydrodynamics, or SPH. Unlike a regular particle system which typically accounts for only collisions, SPH computes viscosity and repulsion forces as well, which make the particles splash and puddle as if they were part of a real fluid. Additional PhysX features in the game include tarps, curtains, rag dolls, and rigid bodies.


Cryostasis Screenshots

To show off the visual effects in Cryostasis, NVIDIA provided us with a technology demo constructed using some of the in-game environments. To pull off the effects in Cryostasis, thousands of fluid particles are simulated on the GPU. In the first room in the demo, there are just under 30,000 fluid particles being rendered which interact realistically with the environment and other particles. The screenshots above don't do the effects justice, however, so we recorded a short video to show off some of the effects in real-time.

Cryostasis Smoothed Particle Hydrodynamics In Action

The video above doesn't show the tech demo in its entirety, but we tried to show you some of the more impressive effects in the clip. As you watch, notice how the fluid particles interact with the characters, environment, and each other, and how cloth moves differently whether it's frozen or warmed up.

To take advantage of the PhysX acceleration in Cryostasis, a CUDA enabled GPU, such as NVIDIA's GeForce 8, 9 or 200 series of GPUs, is required. For good performance (above 30 FPS) at more mainstream resolutions, NVIDIA recommends a GeForce 9800GTX+ or better graphics card. But for HD resolutions, a GTX 200 series card is recommended. If a PhysX-enabled card is not present in the system, PhysX can be simulated on the CPU, but performance takes a nosedive. We did some quick tests in a Core i7 965 Extreme powered system equipped with a pair of GeForce GTX 280 cards running in SLI, and found that the average frame rate at 1680x1050 with the game engine set to its "high" quality mode was 58.5 FPS with the PhysX simulations running on the GPUs. With PhysX simulated in software, i.e. on the CPU, the demo was basically a slide show--think under 10 FPS on average.

If you'd like to check out the Cryostasis PhysX technology demo for yourself, it will be available for download on the nZone website soon.