Alice Physx Comparison Essay

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Looking for other areas of the game to enhance, Spicy Horse and the PhysX team decided to utilize the Clothing component of the APEX toolset. Comprised of five modules covering Clothing, Destruction, Particles, Turbulence and Vegetation, APEX is designed to save developers time and money by allowing programmers to focus on game code and not the development of extra tools and features. Instead, designers and artists can easily use the interface-driven modules to create, generate, and import high-quality game assets and supporting code that adhere to the same collision rules as the aforementioned PhysX Particles.

In Alice’s Victorian London there are numerous washing lines adorned with clothing that are otherwise static when PhysX is disabled. With PhysX enabled the clothes react realistically as Alice passes through, swinging and swaying as they lose momentum following her interaction, and despite its name, the Clothing module can be used to accurately simulate other objects also. Inn this case, curtains in Alice’s home, and loose newspapers blown by the wind down the dilapidated streets.

Alice gets a face-full of laundry, the clothing moving realistically as she passes. After Alice has passed the clothing gradually loses momentum and returns to its original position.

By adding these small but subtle details, a consistency now exists where all cloth is animated, not just Alice’s dress, removing a potentially immersion-damaging discrepancy.

APEX Destruction has also been leveraged for Madness Returns, as mentioned earlier. Stone slabs, chessboards and other terrain elements can be accurately smashed apart by melee attacks and Alice’s destructive hobby horse, but how does the game render this destruction when the areas in question are solid objects when PhysX is disabled? Schoemehl explains:

“With APEX Destruction artists can take existing assets and fracture them in the PhysX Lab tool based on a number of parameters. Using this tool they specify how the mesh fractures and tweak parameters to establish material strength and a support structure, and then set up the characters to cause damage by way of impacts. With these relatively simple steps our Destruction effect is created. Not only does APEX Destruction give us this instant flexibility to make these effects quickly, it also brings a great level-of-detail system along with large scale and manageable destruction.” In other words, the developer imports the existing chessboard models and textures, deforms them using the Lab tool, saves them, and then imports them back into the game, saving said developer a lot of time and money.

Using PhysX Lab to dictate the properties of the Chessboard and how it reacts when destructive forces are exerted upon it.

The in-game result. Note how the pieces of the board are able to sit on top of one another once destroyed, making the destruction appear more realistic. Like the particle effects, destruction is completely organic and not animated ahead of time (also known as pre-baking).

Furthermore, destruction is utilized to enhance in-game events that every player, regardless of platform, will see. In these instances extra destructive elements are added, destroyed objects fracture and splinter realistically during their destruction, and smaller destructive elements may be added, such as rocks that tumble down a cliff face as the main boulder hurtles towards the ground.

A cliff is destroyed, the rocks reacting and tumbling realistically. With PhysX enabled extra particles and rocks are featured in the scene, making it appear more realistic and action-packed.

All three technologies combined: Fluid coats the terrain, Particles emanate from Alice’s attacks and fill the air, and Destruction debris tumbles from the cave walls, falling realistically to the ground below.

Developed in concert with Spicy Horse’s developers in Shanghai, the PhysX effects in Alice: Madness Returns push the limits of the realism-led technology further than ever before. In the space of two years, since the introduction of PhysX with EA’s Mirror’s Edge, both the software and hardware have progressed massively, allowing for thousands more particles per scene and the introduction of advanced Smoothed Particle Hydrodynamics, used initially in a more basic manner in Cryostasis: Sleep of Reason.

With the integration of NVIDIA’s PhysX and APEX technologies into Epic Games’ Unreal Development Kit, any developer in the world, indie or otherwise, can make use of it to accelerate and enhance their games. And with Epic’s recent Game Developers Conference demonstration pushing the limits of APEX Clothing and game technology even further, it is an extremely exciting time to be a PC gamer.

We hope you found this article informative. If you have questions or comments please post them in this forum thread. Thanks!

Archive for the ‘Particles’ tag

PhysX Research: adding physics to animated characters with Oriented Particles

Another interesting research paper was published by Dr. Matthias Müller-Fischer, PhysX SDK Research Lead in NVIDIA.

Update:Oriented Particles solver through CUDA

It is called Adding Physics to Animated Characters with Oriented Particles and it further expands oriented particles approach with techniques for simulation of clothing on animated characters.


We present a method to enhance the realism of animated characters by adding physically based secondary motion to deformable parts such as cloth, skin or hair. To this end, we extend the oriented particles approach to incorporate animation information. In addition, we introduce techniques to increase the stability of the original method in order to make it suitable for the fast and sudden motions that typically occur in computer games. We also propose a method for the semi-automatic creation of particle representations from arbitrary visual meshes. This way, our technique allows us to simulate complex geometry such as hair, thick cloth with ornaments and multi-layered clothing, all interacting with each other and the animated character.

GPU PhysX in Alice: Madness Returns

Alice: Madness Returns, highly anticipated sequel to original American McGee’s Alice, and first game with GPU PhysX support for this year. As always, we have prepared comparison PhysX video – for your viewing pleasure.

Update:PhysX benchmarks roundup

Update #2:Comparison PhysX screenshots available

GPU PhysX content in Alice: Madness Return can be characterized as “Particle Madness“. In a good way – this game contains probably most rich and diverse physically simulated particle effects, of all games with hardware PhysX support. From habitual and universal debris, chunks, smoke and dust (emitted either by player’s weapons or enemies) to environmental particles (dynamic leaves, ash, bubles, etc) and place-specific effects.

Physical simulation of goopy oil-like substance, that is spawned when black “Ruin” beings are damaged or killed, requires a special notice. During intence fights, up to 10 000 SPH fluid particles, which are colliding with level geometry and reacting to player’s movement, can be processed simultaneously.

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PhysX Research: Eulerian Water Simulation and Solids through Oriented Particles

Two new research papers have landed on a homepage of Dr. Matthias Müller-Fischer, PhysX SDK Research Lead in NVIDIA and NovodeX co-founder.

Fisrst one, called “Real-Time Eulerian Water Simulation Using a Restricted Tall Cell Grid“, presents further impovements to the real-time hybrid fluid solver, that we were able to see in recent demos like Lighhouse and Raging Rapids Ride.


We present a new Eulerian fluid simulation method, which allows real-time simulations of large scale three dimensional liquids. Such scenarios have hither to been restricted to the domain of off-line computation. To reduce computation time we use a hybrid grid representation composed of regular cubic cells on top of a layer of tall cells. With this layout water above an arbitrary terrain can be represented without consuming an excessive amount of memory and compute power, while focusing effort on the area near the surface where it most matters. Additionally, we optimized the grid representation for a GPU implementation of the fluid solver.

To further accelerate the simulation, we introduce a specialized multigrid algorithm for solving the Poisson equation and propose solver modifications to keep the simulation stable for large time steps. We demonstrate the efficiency of our approach in several real-world scenarios, all running above 30 frames per second on a modern GPU. Some scenes include additional features such as two-way rigid body coupling as well as particle representations of sub-grid detail.

We badly want to see this one in further releases of PhysX SDK 3 or APEX.

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Alice: Madness Returns will feature GPU PhysX effects

In a recent promo video for upcoming GTX 560 GPU, NVIDIA has spoiled next game with support of GPU accelerated PhysX effects – Alice: Madness Returns, sequel to American McGee’s visionary classic “Alice” title.

UPDATE:Comparison GPU PhysX video

Starting at 1:34, comparison PhysX sequences are showcased. According to the video, GPU PhysX content in Alice will include (following list may be not full) destructible environments..

..volumetric fluid effects (for example, oil-like fluid from damaged enemies)..

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APEX PhysX in Mafia II: Particles

We are completing our overview of APEX PhysX content in Mafia II by this video,  showcasing most noticable effects based on APEX Particles module.

Previous comparison video, dedicated to APEX Clothing module, is available here.

APEX Particles effects are including:

  • Various dynamic debris (concrete fragments, glass pieces, wood splinters, etc) from bullet impacts.
  • Additional physically simulated chunks from explosions, car crashes, wheel slip, trash cans, mailboxes and other destructible objects.
  • Vehicle tire burnout effect -  realistic fluid smoke, which reacts to environment and character/NPC movement.
  • Up to 3000 (APEX Medium settings) or 10 000 (APEX High settings) unique particles on screen.

Sum: You can find dynamic particles almost in every single GPU/PPU PhysX game, but in Mafia II particle effects are close to their perfection – realistic collision simulation, various particle types (for both graphical mesh and physical behaviour), LOD based resource management (particles are not dissapearing over time, like in earlier games) – and, most important, pretty decent performance.

If your system can handle such effects, we recommended to leave them enabled, or you’ll loose significant piece of game’s immersion.

Finally, keep an eye on Mafia II GPU PhysX info mini-site for additional information and comparison screenshots.

Mafia II Demo: tweaking PhysX performance

Yes, all that dynamic clothing and particle effects are cool, but actuall performance of Mafia II with APEX PhysX effects set on “Medium” or “High” isn’t very fascinating – even GTX 480 users may met some annoying fps drops and lags. Fortunately, there is a way to tweak APEX content a little.

Note: Interested in how exactly APEX Framework is being used ? Visit Mafia II GPU PhysX profile page for additional information.


Most performance is devoured by APEX Clothing module (why ? because it is running on CPU, not on GPU), that is responcible for realistic clothing simulation on main and several NPC characters.


Update #2: following tweaks will work with final version of Mafia II

1) Disabling all clothing

If you can live without flowing Vito trenchcoat and woman’s skirts, you can simply follow the path

\Steam\steamapps\common\mafia ii( – public demo)\edit\APEX

and delete (don’t forget to backup) directory named as


This will remove  certain APEX assets, and all character clothing will revert to static skinned mesh (like with APEX set to “Off“), but all particle effects will stay !

Result ? No more realistic cloth, but huge fps increase. 70 average fps vs 25 fps without this trick (APEX set to High, single GTX470 is used, GPU PhysX enabled).

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