Very interesting PhysX Fluid Simulation demo was revealed by a user Finalspace on German Delphi OpenGL Community forum.

Written from scratch on C++, based on PhysX SDK 3.0.2 and OpenGL, this demo is showcasing Smoothed Particle Hydrodynamics (SPH) fluid simulation in a basic environment.

However, the amount of options is appealing – you can choose from various scenes, change fluid parameters, add rigid bodies or more particles (up to 262 000), apply forces to the fluid, switch rendering modes – PhysX Fluid Simulation is a fully functional playground, more advanced than original PhysX Fluids demo from NVIDIA.

You can download PhysX Fluid Simulation v 1.2 from our server (1.7 mb), or from original thread.

Screenshots:

Controls:

(R) – reset scene

(H) – enable/disable GPU acceleration.

(S) – switch Fluid rendering mode (screen space fluid, particles, point sprites).

(Arrow Keys) – apply forces to the fluid.

(L) – cycle simulation scenario and collision geometry (normal box, small box, large and flat box, tall and narrow box).

(1-6) – choose object to be added to the scene

• 1 – rigid body: box
• 2 – rigid body: sphere
• 3 – rigid body: capsule
• 4 – fluid: one particle
• 5 – fluid: 512 particles
• 6 – fluid: 65 000 particles

(Space) – add new object to the scene

Recently, we got a chance to lay our hands on a bunch of high-resolution, never-seen-before screenhots from Art Gallery demo – it was used by NVIDIA to demonstrate APEX Destruction capabilities at GDC 2011.

For you viewing pleasure.

Art Gallery demo is featuring full-scale hardware acceleration of Rigid Body physics simulation (GPU Rigid Bodies, GRB) – we are hoping to see it live in APEX 1.1 and November/December UDK.

As good tradition, several interesting physical demos were presented during GTC Day 1 Keynote by Tony Tamasi, Senior Vice President Content and Technology in NVIDIA.

First one was showing some high-fidelity smoke simulation, with particles interacting fully with characters, producing nice fluid and turbulent behaviour.

Second one, more impressive from our opinion – water simulation inspired by Lighthouse scene from Stanford Computer Science, but this time running in realtime, on one GPU.

Hybrid solver, based on heightfiled fluids and particles – very similar to the one in Raging Rapids Ride – was used.

Of course, those are just technical demos, but they are giving a good glimpse on what future games and future physics engines (PhysX SDK 3.x, anyone ?) may bring us.

Original NVIDIA PhysX Fluid Demo is nice indeed, but it is not using fluid simulation to it’s full potential – there is only two scenes, level geometry is way too basic and water flow is too simple.

That’s why our fellow reader, known as AquaGeneral, desided to pimp Fluid Demo a little, buy replacing original models and, thus, providing more interesting usage of fluid sim.

[08.01.2011] Update: new model – “Two Story Building” – available. Mod reuploaded.

Update #2: If you want to create custom level to yourself, please refer to PhysX Fluid Demo Modding Guide.

Three new variants of initial “Pumping Station or something” scene were added:

1 – “Building”

2 – “Pool”

3 – “Two Story Building”

Installation instructions:

1) Install original Nvidia PhysX Fluid Demo. Please note that you need PhysX System Software to be installed too.

2) Download Fluids Mod.zip from our server (180 kb. Direct download links won’t work).

Note: virustotal report - 100% clear

3) Extract the zip archive to “\Program Files (x86)\NVIDIA Corporation\NVIDIA PhysX\Demos\Fluids“  folder

• Overwrite the two texture files, “corridor.bmp” and “corridor_n.bmp” – this is necessary because new models weren’t designed to be textured.

• Copy “Scene” folders content and replace them over the original “corridor_new.obj” and “corridor_new_collision.obj” files. Only one new model can be used at the time.

Note: since Fluid Mod is replacing original files, don't forget to back up them firstly.

You may notice some artefacts at the beggining of the simulation, but this is normal.

Don’t forget that you can use “1″ key to interrupt the emitter (and prevent older particles from being deleted), and, thus, observe water flowing through the whole level.

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.

Important: Mafia II may have some issue with PhysX System Software installation. If you experiencing major slowdowns, reinstall it using 9.10.0512_SystemSoftware package from \Steam\steamapps\common\mafia ii – public demo\3rd folder.

You also may wanna try new 9.10.0513 PhysX drivers

PART I – APEX CLOTHING

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: tweaking APEX Particles effects

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

Cloth

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).

2) Disabling all clothing except for Vito

Revert Cloth folder to it’s place.

Delete all files (backup), except for those starting with “VIT*“, and files named “m2skeleton” and “ClothRemapTable“.

Note: if you experiences stability problems after selectively removing cloth files, try to delete certain lines from ClothRemapTable.xml, corresponding to files that were ommited.

Voila ! Fully dynamic clothing on Vito, without NPCs draining your fps with their unnoticable cloth skirts and jackets.

This is a place near Vito’s house – running around 20-25 fps previously, thanks for those NPC womans skirts. After tweak – 60+ fps.

3) Disabling clothing for NPC pedestrians only

If you want to disable clothing simulation for NPC pedestrians, but leave it for Vito and his buddies (Joe, Henry, etc):

Delete (backup, of course) files starting with “CCI*“, “CIT*“, “CME*“, “CPR*” and “CSI*“

from folder

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

All other files must remain (if you applied any clothing tweaks previously, Cloth folder must be reverted to its original state – before using this method).

———

And finally. With our tweaks it is possible to play Mafia II with APEX PhysX enabled – purely on CPU.

All fancy particles and impact debris (our CPU was enough for APEX Medium settings, GPU PhysX disabled in drivers), some clothing simulation – running around 30+ fps.

Looks like a nice deal for non-hybrid ATI users.

———

Some screenshots with clothing tweak №2 – APEX PhysX is set to High, graphics and physics are calculated on single GTX470. Particles are in place, Vito’s clothing is fully simulated.

PART II – APEX PARTICLES

In order to increase game framerate even further, APEX Particles effects (debris from bullet impacts, smoke, etc) can be removed too.

Simply delete (backup first) Effects folder located at

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

If you want to find a performance compromise, you can disable, for example – particles and clothing on NPC, but leave clothing on Vito – just like on the screenshot above.

Of course, system is more flexible – you can delete only certain .aea files (stands for APEX Emitter Asset I believe), located at

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

- responcible only for certain particle effects.

For example, deleting burnout.aea will vanish pretty demanding “tire burnout” dynamic smoke (all other particle effects will remain).

or, if you’ll remove vybuch_auto.aea – you will not see chunks from car explosions anymore.

Large field for experiments.

Any use of article content without permission is prohibited.

If you haven’t played Mafia II demo, and still wondering what are differences between APEX PhysX effects setting, we have prepared a small video, showcasing several APEX settings using built-in benchmark.

Update: Tweaking PhysX in Mafia II – huge fps increase without noticable difference.

Update #2: comparison PhysX videos for final version, covering APEX Clothing and APEX Particles modules usage in details.

As you may notice, when APEX is set to “High” – a lot of dynamic particles (impact debris, chunks from explosions, smoke) are added, and simulated clothing for characters as well. Detailed effects description is available here.

Unfortunately, this one is not even close our usual detailed comparison videos, so – our apologies.

Full scale APEX Effects comparison is planned only after Mafia II release.

While you are waiting for Mafia II Demo, planned to be released just in a few hours, you can read the preview of APEX/PhysX content, prepared by Techgage in their “Taking a Look at Mafia II and its PhysX Use” article.

Demo includes “Benchmark” mode, and that’s how it’s look like:

Update: Our PhysX Comparison video using built-in benchmark. In addition, APEX comparison and showcase videos roundup.

Update #2: Tweaking PhysX in Mafia II – huge fps increase without noticable difference.

Update #3: Mafia II Demo – PhysX Benchmarks roundup

Update #4: Mafia II GPU PhysX profile – comparison video, screens and other additional info.

APEX/PhysX Features:

• Physically simulated clothing for main character and additional characters
  • Custom wind simulation that creates a more dynamic movement of clothing as the characters walk around and interact with the environment.
  • Force fields from explosions and interact with clothing, making those explosive moments even more immersive
• Up to 3,000 unique particles on screen at any given time (10,000 at High settings).
• Particle effects including dynamic collision, mass and kinetic simulation, and force fields from explosions that move and displace particles along its path.
  • Destruction particle debris from cement, wood, glass, dirt, and more
  • Weapon impact that creates dynamic smoke and kinetic persistent particles
  • Garbage moves and exists in the world of Empire Bay and reacts to effects like force fields and character interactions
  • Tire burnout while driving produces dynamic smoke and particles including fluid movement simulation and particle velocity and trajectory
• Character clothing on all character models is rendered entirely on the GPU when using a dedicated PhysX card which can be anything from a GT 240 to a GTX 480.

With APEX set to “Off”:

• Clothing on character models is not realistically generated but graphically simulated. It does not interact with the physical world.
• Particle debris is sprite based and does not contain physical properties. Particles will not interact with the environment and are not persistent.
• Smoke is staticly generated with no physical properties and will not interact with the physical world.

P.S. Judging by demo, additional APEX PhysX content is optimized for CPU execution better..

..than previous games, like Dark Void.

Unfortunately, still not enough for decent fps and comfort gameplay (at least, with our C2Q 9400 CPU).

PROBLEM: Strange. According to PhysX Visual Indicator, PhysX effects in Mafia II are running on CPU, even if GPU PhysX is enabled in drivers – with this newest 09.10.0512 System Software.

I wonder if that’s the reason of low fps. Can anyone confirms this ?

SOLUTION: you need to reinstall PhysX drivers.

Uninstall current one, than install PhysX_10.05.12_9.10.0512_SystemSoftware package manually,

from \Steam\steamapps\common\mafia ii – public demo\3rd

For those of you who are still playing with old Nvidia PhysX Fluid Demo (version 1.0.0.9, released in 2008 with first PowerPack) Nvidia has prepared a new, slightly updated variant – PhysX Fluid Demo ver. 1.0.1.3.

Update: Modding of PhysX Fluid Demo

Release notes:

• Allocate only 64MB of VRAM heap instead of 128MB
• Adjusted text output to not conflict with the PhysX Visual Indicator
• Added option to toggle the display of all text (in screen space) on/off.

You can download PhysX Fluid Demo ver. 1.0.1.3. from here (19 mb)

Alternative download from physxfiles.com (direct links won't work)

Supersonic Rocket Sled – DX11 and PhysX technology demo from Nvidia is finally available for download (221 mb). Unfortunately, you won’t be able to run it until you have GTX 400 Series GPU.

You can download Supersonic Sled demo from here

Apart from Supersonic Rocket Sled demo all of you are probably familar already, for GF100 launch Nvidia has prepared another technical PhysX demo, called Raging Rapids Ride, with boat riding down a montain river – maybe not so impressive in graphics aspect, but with intensive and complex real-time fluid simulation.

It using PhysX SDK based objects with custom hybrid water simulation, utilizing both heightfield fluid solver and particle simulation.  Boat behaviour is a little choppy, escpecially when it collides with waterside surface, but water simulation looks very impressive.

Update: You can download Raging Rapids Ride demo here

Grid based shallow water flowing pass a terrain with high slope is automatically turned into particle waterfall, and than – back to heightfield water (thus, two different fluid solvers are used simultaneously).

Dynamic wakes are generated, as boat mover along the river. When solid objects impacts with water they generate waves, splashes and sprays.

Foams swirl and show off the vortices, as they are advected along the water’s velocity field.

Finally, scene includes some tearable cloth banners, sofbody based plants and floating logs (with properly calculated buoyancy).

Interesting detail – apart from fact that this demo is limited to Nvidia GPU only, it includes multi-threaded CPU implementation of all physics simulations (up to 8 threads can be used). However, even with sufficient load of all four cores for our C2Q 9400 CPU, average framerate is around 5-8 fps.

10-12 fps – on a single GTX 275. And ~30 – with dedicated GTX 260 GPU.

Sum: interesting demo, but mostly in terms of fluid simulation variety and complexity – graphics isn’t that impressive, boat and camera controls aren’t very friendly (when you are trying to control them).

But it’s good to see Heightfield Fluid solver in action finally – it was promised to be implemented into PhysX SDK for years. Keep your fingers crossed, as it may be already included in PhysX SDK 3.0.

We believe that Raging Rapids Ride demo is going to be available for public download soon enough.