AGEIA PhysX: Make physics fun again.

Alright, when was the last time you got excited about Physics? If the answer is "never", then here is a reason to revise that judgment. Don't worry, you won't have to deal with the actual physics but the virtual world inside games will finally be able to mimic real-life conditions more closely.

Note: Epinions is working in mysterious ways. I had this posted under the original category, which now is inaccessible. So I decided to move it here. I also deleted the other (ghost) entry.


IN A NUTSHELL

PhysX is new and therefor expensive and still hard to find. Should you be lucky to have gotten one of those (right now as part of select systems like Dell's XPS 600), the instant gratification may wear relatively thin soon after exploring the demos. With the release of Ghost Recon 3, however, one first step is done to make this hardware worthwhile. Others are scheduled, but right now that's about it beyond the demos by Ageia. Look out for Unreal Engine 3 later this year to find another reason to spend $250-$300 (once the card is available as an accessory).

BFG is one of the two early adopters to the technology and the 128 MB version might be considered the entry level model while Asus' 256 MB promises to be slightly more advanced -- and expensive. Either way, the PhysX engine is a hardware supported physics engine that's poised to make Havok 3.0 look very dated. Of course the latter doesn't have the steep price tag attached to it either.

Currently, the impact of Ageia's physics engine is rather limited in support, but important titles are lined up. With Ghost Recon being the first to support PhysX, most effort went into more realistic graphics by calculating debris and smoke influenced by objects better. While this is only a fraction of PhysX potential, it's also most likely the level of support games might be able to implement without alienating those gamers without "PhysX Inside".

Overall, PhysX presents a great opportunity for PC gaming since it's too late for implementation in the XBox 360 and maybe even the PS3 -- aside the hefty price tag that may not work for consoles anyway. Provided, developer support for Ageia's technology is good, gaming on the PC might gain back the much needed edge -- though be it only for 2 - 3 years until the next generation of consoles is ready for battle. (However, the Cell processor in the PS3 might be quite capable to implement nearly as complex physics via the included nine cores.)

The software side of PhysX might find its way much quicker on every desktop since it does not require the hardware to work and does scale with the available hardware.


WHY PhysX?

Thinking back to the early 1990s, Ageia's Physics Processing Unit has striking similarity to discrete Math Co-processors supporting Motorola's 680x0 and Intel's x86 architecture. Despite it all being about math (hence "computer"), certain tasks are too involving for a general purpose CPU. Complex math algorithms being one of those cases where an expression can be solved by a math coprocessor in a single cycle while a CPU would require a program for that and essentially consume several cycles for the same result.

A physics processing unit aims essentially for the same thing. By providing physics specific algorithms in the hardware, the processing time for related complex equations could be greatly reduced by simply providing specific processor with common elements encoded in the hardware. This works pretty much like building blocks and the CPU would handle one small block at a time (ignoring multi-core processors) while a physics engine get quicker to the finish line by handling much bigger chunks if not the whole equation at once.

The natural path for the PPU would be the one of the math co-processor and eventually end up as a building block in the CPU. Unlike graphics (GPU) the development of features and power in a PPU may not be as intense. With an agreed-upon feature set and enough computing power integration might become an option 2 - 3 years from now. That is, however, only if Ageia provides no-hassle licensing. At the current state of development, it remains to be seen if IBM's Cell processor can compete with the power of a dedicated PPU or simply adopts the concept and integrates it. This might be easy due to the modular structure of multicore processors.

Currently PhysX includes
1. Complex rigid body object physics system
2. PhysX FX smart particle system
3. Volumetric fluid creation and simulation
4. Cloth and clothing authoring and playback
5. Advanced character control
6. Ray-cast vehicle dynamics


FEATURES

Software vs. Hardware: [****-] While Ageia is actually both Software and Hardware, in the comparison to the closest competitor (Havok 3.0) it's heavily hardware supported and allows to process much more equations while freeing the CPU up as well. In the absence of a card, the Ageia driver works in full software mode (with restrictions) and poses a direct comparison to the Havok engine. To the degree it's supported, PhysX shows a more advanced environment even in software mode, but really comes to live only with the card installed. The Havok software is easy to upgrade with new features or optimizations while the hardware portion of the PhysX is locked in a certain development stage. However, dedicated hardware typically is faster and prevents the CPU from becoming the bottleneck.

Games: [****-] The initial line-up of developers is impressive, but Ghost Recon 3 is also the only one that is currently available as a demo (retail to follow on May 5th). Explosions are incredibly real with lots of debris showcasing the power of PhysX. However, the difference to pure software emulation is similar to setting a graphics board from high detail to medium or low detail. Blame the novelty of this technology if you must, but the majority of computers may not have this kind of hardware for a few years, and that will be the biggest hurdle in establishing PhysX as a standard which then allows to more deeply implement physics into games. Ghost Recon 3 shows more graphics refinement than gaming revolution with its implementation. Look out for a possible exception when Unreal engine 3 (UT2007) surfaces later this year -- apparently implementing destructible environments. Either way, it is unlikely for released games to be "patched" and support PhysX.

Currently announced ...
- Tom Clancy's Ghost Recon Advanced Warfighter
- Rise of Nations: Rise of Legends
- Bet on Soldier: Blood Sport
- CellFactor
- City of Villains
- Gunship Apocalypse
- Unreal Tournament 2007
- Sacred II
- Loki
- Dogtag
- Fallen Earth
- Crazy Machines 2
- Arena Online
- Infernal (Formerly Diabolique)
- Warhammer MMORPG
- Eye of the Storm
- KARMA
- Vanguard: Saga of Heroes
- Alpha Prime
- Abyss Lights: Frozen Systems
- Highlander
- Dark Basic Pro
- Blink 3D
- Fritz Chess 9

The PhysX-only CellFactor aside, Unreal Engine 3 is likely to be the most in-depth implementation of PhysX with ...
- "rigid body physics system supporting player interaction with physical game object, ragdoll character animation, complex vehicles, and dismemberable objects."
- "all renderable materials have physical properties such as friction."
- "Physics-driven sound."
- "Fully integrated support for physics-based vehicles, including player control, AI, and networking."
- "UnrealPhAT, the Visual physics modeling tool built into UnrealEd that supports creation of optimized collision primitives for models and skeletal animated meshes; constraint editing; and interactive physics simulation and tweaking in-editor."
(info from the press release)


Applications: [***--] Game development environments like AutoDesk 3dsMax, Softimage xsi, and Alias Conductor are the most prominent professional applications currently supported or announced. Unfortunately rigid body mechanics may be too limiting for CAE (computer aided engineering) software like Pro/Engineer Mechanica, ANSYS, MoldFlow and other time consuming finite element analysis programs. Despite the potential there is currently no information available on how applicable the algorithms in the PhysX card may be for those examples. Should it prove feasible, real-time crash analysis and structural calculation while making changes would be a huge improvement over calculations currently taking up to several hours (for more complex problems). However, the market would be small compared to gaming and potential solutions probably carry a professional price tag too.

Current partners ...
- Autodesk 3ds Max
- Collada (3ds plugin)
- Ephere Ornatrix (3ds plugin)
- Alias Conductor
- Discreet Sparks
- Softimage XSI
- RAD Granny 3D
- FerReel Animation labs

Graphics: [****-] While often wrongly classified as a graphics card, it's currently used to support the physical aspects of graphics only. And the results are often stunning. Look at the smoke that flows around objects or tons of debris being scattered accompanied by smoke trails and realistic bouncing. Flame throwers have never been more real either. When supported, it makes the $250 investment worth every penny. However, I realize that this might be a subjective thing. If you got by with a 2 - 3 year graphics board (i.e. Radeon 9700) without the craving for more, the improvements provided by PhysX may not be useful to you and frankly your graphics card would probably be incapable of rendering the richer graphics details. (The increased number of polygons in more detailed explosions etc. adds to the workload of the graphics card and potentially slows it down. Simply having the same polygons behave more accurately as in cloth effects has no significant impact on your graphics performance.)

Interaction: [***--] First information for upcoming DirectX 10 (Windwos Vista only) is showing great improvements in interactive environments, and while that is currently CPU based it might be an "easy" shoe-in for Ageia's PhysX processes. Until that's confirmed, we're left with game developers that dare to support a rather small community of extreme gamers. (i.e. CellFactor) Until a physics engine becomes standard, interactive environments are most likely to remain watered down and not essential to the game play. So for the next 2 - 3 years the majority of games might improve certain behaviors, but it's going to remain eye candy for the most part. However, you can always hope that developers think modular enough and allow the PhysX engine to be optional. Fully interactive environments, however, may still be a good way out.

Performance: [****-] Since the PhysX card does not render the polygon into grpahics, a dedicated video card is still required. Due to the task division, one might see actually a reduction in performance should your graphics card be unable to handle the occasionally increased number of polygons. While I have not experienced such thing with my x1900XT, there have been reports to that extend with Ghost Recon Advanced Warfighter (which reportedly have been resolved with the latest game patch and PhysX driver). On the other hand, examples like torn cloth or fluid dynamics, where polygon numbers basically remain the same, see vast improvements in the behavior and performance. Memory at 128 MByte seems generous since PhysX is a pure number cruncher very similar to a previously discrete FPU. At the current level of support, even the BFG 128MB card is quite capable of handling what's thrown at it. More memory might be good to overcome the PCI bottleneck when needed. I guess we may see 512 MB cards in the second generation, but developers will have to consider the 128MB as the current baseline. Large fully interactive environments may require a access to the main memory to avoid the bottleneck PCI bus (127 MByte/sec). The PhysX processor is currently using high performance memory (GDDR3) so far only found in graphics cards.

Note: Unless your game is specifically designed to support the Ageia PhysX engine, it will not benefit from this hardware (at all). This is due to DX9's lack of an interface for advanced physics. Likewise, benchmarks like 3DMark06 don't make use of the PhysX engine either though some demos in this test reportedly use it in the latest patch.

Power: [***--] Compared to high-end graphics cards or CPUs, the PhysX hardware comes in at a mere 40W. Sure, that may be 1/3 of mentioned examples, but it still adds to a system's consumption. Unlike for example an x1900XT there is no powersaving mode (i.e. switching to 500 MHz for 2D and 650 MHz for 3D). That also means that most of the time it will be burning a full 40W whether it's used or not. In light of the limited support of this hardware, a "sleep mode" would be beneficial to (a) get load off your PSU during undemanding tasks like reading this review on the Internet and (b) help save a few cents of the monthly power bill.

Cost: [****-] Until mid May 2006, PhysX only came bundled with few select computers like Dell's XPS600 and the upgrade often was too expensive (despite the $250 option). BFG made first cards available mid May 2006 for $299 ($268 street). That's also not cheap considering the marginal return due to meager game support as of today. It's also is about the same as an entry-level high performance graphics card (i.e. Radeon X1800 XL). Then again, it's new technology and early adopters are not only driving progress but also paying the price to have it now. Further, expect about 2 - 3 generations of more powerful revisions before it might level out similar to CPUs. Until then it might be a wild goose chase. Irony has it that if eveybody is waiting for full implementation before buying into PhysX, we might never see a next generation (as it's making no money). Hold on tight, it's going to be a bumpy ride with real gravity, friction and inertia. (Pun intended!)

Future: [tbd] While I am not in the business to predict the future, there are realistically only three possible scenarios for the PhysX technology. Restrictive licensing might push extensions of the math unit to the degree possible and eventually eliminate PhysX. My favorite would be an adoption by AMD and Intel (and IBM) and essentially integration in next-gen multi core processors. However, that potentially eliminates the inventor of the technology (Ageia) as the need for discrete PC cards would go away. Ageia is a technology company and not a manufacturer anyway, and most likely in favor of licensing their technology to as many manufacturers as possible.
Either way, the PPU would have to outpace improvements in CPU speed which may be difficult in light of the 9 cores in the Cell processor. Judging from the large chip (currently in 130nm technology), there is plenty room for improvement by moving to finer processing technology (90nm or 65nm) and essentially smaller dies that run at higher frequencies.
Should the PhysX PPU remain on the current path, software developers may not support it on a broad scale since it is a rather costly accessory. Judging from sound cards the market would then be restricted to enthusiasts and the whole potential never be achieved due to a restricted market. Fortunately, Ageia was able to gather important developers and is off to a possibly good start with a possible software-only implementation. This might replace Havok on a broad scale, and allows to step it up another notch with the card installed (for all those that don't mind investing $300 for the sake of even more detail). Then again, alternative technologies might emerge and not only ATI and nVidia are pushing to move physics calculations into to GPU (DX10 capable cards at least).
Don't underestimate the power of ATI and nVidia as the polygons are already stored in the graphics card and adding a physics unit to that might have an advantage -- besides the obvious market presence of both companies.
It appears that the upcoming 1 - 2 years will be both exciting and confusing to say the least.

PC exclusive?: The hardware is ging to be an exclusive for the PC market for a while, but Ageia proudly announced licensing of the technology to both PS3 and XBox360 developers. In that case, PhysX runs in a 100% software mode which is supported by the up to 9 cores of the Cell processor. This is both good and bad for PCs, as the developers can use it on all platforms and increase their usage of this technology. PC gamers might reap the benefits simply by lowering the threshold in implementing PhysX. On the other hand, the degree of implementation may be determined by what's possible on the XBox360 (the weakest processor of the next-gen consoles). Hence PhysX hardware may not be fully utilized for a while. (The same is true for high-end graphics cards on the PC.)

© 2006, theuerkorn


ONLINE RESOURCES

BFG PhysX Card
- http://www.bfgtech.com/physx/index.htm

AGEIA Demo Footage
- http://www.ageia.com/physx_in_action/footage.html

Licensed games
- http://www.ageia.com/physx/titles.html


AGEIA - The name stems from the country of origin of the 5 founders of the company: America , Germany , Egypt , India and America.


UPDATE [02-JUN-2006] - To my surprise, a few games like City of Villains announced patches. However, this is mostly to improve effects (similar to Ghost Recon 3). Given the nature of a patch, changes cannot be significant and results should not be used as a benchmark for what this card can do. (There is much more to physics.)

UPDATE [20-JUN-2006] - Persistent rumors are circulating that the PhysX-only game demo "CellFactor" (ETA late 2007) can be played without an actual PPU hardware installed. It should not surprise anybody that PhysX can be forced into software mode and apparently a fast CPU like AMD's FX-62 may be capable to process the physics with minor reduction in frame rates while maintaining good physics. However, despite my AMD Athlon64 X2 4200+ and 2 GByte of memory, the drop in performance was significant and reduction in physics quite noticeable, yet it remained playable to a limited degree in low graphics mode. To find out yourself download and install the Cell Factor demo along with the latest PhysX drivers (2.4 or later). Adding "EnablePhysX=false" to the options in the command line (target) in the shortcut properties does the trick.

UPDATE [12-OCT-2006] - Ageia released a benchmark called RealityMark (based on CellFactor) showing the "true" difference between hard and software, claiming 1000% improvement for PhysX over the average system (dual core). This may put claims to rest that software-only PhysX is just fast, though it remains to be seen if that degree of implementation will ever be realistic for any game.) Anyway, prices dropped and there is almost no good reason anymore not to try it. After all, Christmas is coming up. (If you're waiting for the Havok FX release, be advised that it will likely need a dual GPU implementation like SLI or Crossfire, since apparently one GPU needs to be dedicated to the physics calculation. So the idea to be "cheaper", may not be all that accurate (unless you already have a quad SLI system). Keep in mind that more complex physics often involve a much greater polygon count as well, which is taxing the GPU more.

UPDATE [21-Nov-2006] - RealityMark has been re-released (not requiring to install the old driver anymore). My system is a AMD X2 4200+ w/ 2 GByte of DDR400 and the difference couldn't be more impressive. The score is a whopping 3340% advantage for the PhysX hardware, or 33x faster. This is mostly due to the extensive use of cloth effects in the benchmark, which the CPU simply doesn't have enough computing power for. The difference in actual games should be less impressive, as cloth is not likely to be used that much. Ageia also announced the upcoming release of a PCI-e version of the PhysX board. However, now you're faced with a decision: dual GPU and potentially faster graphics in Non-physX games, or single GPU and PhysX?

UPDATE [10-Jan-2007] - PhysX R.I.P.? I almost missed this one but Ubisoft "quietly" released Rainbow Six Vegas for the PC based on Unreal 3 engine. Despite Unreal having the built-in support for PhysX, it appears that Ubi opted out from using that part. This is especially odd, since both PS3 and XBox360 versions actually do support PhysX (software). The upcoming months with show if this is the first sign for a not-so-bright future for the Ageia hardware. (Especially if UT2007 comes with the same limitations.)