The physics "claims" thread...

Lonbjerg

Diamond Member
Dec 6, 2009
4,419
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After debating on this board, it's obvious to me that a lot of misconceptions muddy the debate.
So I thought:
What better way than to make a FAQ/informative post to clear out a lot of these misconceptions.
So here we go:

Claim #1

"My multicore CPU will do physics just as good, no need for GPU physics."

This is false.
A GPU is superior to a CPU for physics calculations by a MAJOR factor.
I will let Erwin Coumans(Bullet Physics) provide the documentation:

Erwin Coumans said:
GPU NVIDIA Geforce 260:
Profiling: Root (total running time: 0.704 ms) ---
0 -- stepSimulation (99.57 %) :: 0.701 ms / frame (1 calls)
Unaccounted: (0.426 %) :: 0.003 ms
...----------------------------------
...Profiling: stepSimulation (total running time: 0.701 ms) ---
...0 -- synchronizeMotionStates (0.00 %) :: 0.000 ms / frame (1 calls)
...1 -- solveSoftConstraints (75.75 %) :: 0.531 ms / frame (1 calls)
...2 -- internalSingleStepSimulation (12.55 %) :: 0.088 ms / frame (1 calls)
...Unaccounted: (11.698 %) :: 0.082 ms

CPU Intel Quadcore Q6800 at 2.93 Ghz:
Profiling: Root (total running time: 12.511 ms) ---
0 -- stepSimulation (99.96 %) :: 12.506 ms / frame (1 calls)
Unaccounted: (0.040 %) :: 0.005 ms
...----------------------------------
...Profiling: stepSimulation (total running time: 12.506 ms) ---
...0 -- synchronizeMotionStates (0.01 %) :: 0.001 ms / frame (1 calls)
...1 -- solveSoftConstraints (68.69 %) :: 8.590 ms / frame (1 calls)
...2 -- internalSingleStepSimulation (15.21 %) :: 1.902 ms / frame (1 calls

This is the case wether the physics API is called PhysX, Havok or Bullet Physics.
So NO, you CPU is no match for a GPU in physics.
It would be like saying that your multicore CPU would render graphics just as good and fast as an GPU.

Claim #2

"BF:BC2's use of CPU physics looks just a good (or better) than any GPU physics game."

This is really comparing apple to oranges.
BC:BF2 uses Havok CPU physics and thus is limited in the perfomance is can apply to physics and thus resort to scripted physics.

This means that:

- every single wall explosion looks the same.
- every single wall explosion creates an identical hole in the wall time after time.
- every single wall explosion creates the same dead, inactive debris.

A game utilizing GPU physics does this differently, eg. Warmonger as is can use dynamic physics.

This means that:

- every single wall explosion is different aka dynamic.
- every single wall explosion creates a dynamicly whole, depending on the impact of forces.
- every single wall explosion creates interactive debris.
This applies to all other physics effects in general (scripted vs dynamic)

Games that have been acclaimed with doing the "same" on the CPU are eg. Ghostbusters or Star Wars Force Unleashed.

What people for some reason (choose?) to ignore are that not only are the amount of rigid bodies shown a lot less than other GPU physics games and that the debris for destroyed object not only are dead and static (you cannot interact with them) the debris also dissapear into thin air after 10-15 seconds.

This in in no way comparable to eg. games like Mafia II where not only are the debris interactive, but it also remains on the level and dosn't suddenly fade out and dissaper into thin air.

Claim #3

"You must have a NVIDIA GPU to run Physx"

This is also false.

PhysX run on everything from a Cell CPU to a x86 CPU to AGEIA's PPU to NVIDIA GPU's.
The ONLY difference is the amount of performance available on the different platforms.
This lead to that the developer needs to make some choices.

Run all physics effects at the same level of hardware, resulting in that some configuration will run at 1-2FPS while others will run at +30 FPS.

A game doing this is EVE - Online.

It's Character creator run NVIDIA's APEX.
If you have a NVIDIA GPU, the creator runs fluidly, but if you have an AMD GPU, you are forced to run the APEX PhysX on your CPU and you get 1-2 FPS at max settings.

A game doing it in a different way is Batman - AA.

There they limit the physics features being run (When a NVIDIA CPU isn't present) in order to ensure fluid gameplay.

Claim #4

"OpenCL/DirectCompute is much better than PhysX"

This is a claim based on ignorance.

OpenCL <-> CUDA <-> Directe Compute

Those are API's and can be compared.

PhysX <-> Havok <-> Bullet Physics.

Those are physics middlewares and can be compared.

Let look at PhysX.
It's a physics middleware running on CUDA.

Then lets look at Bullet Physics 3.0
It's a physics middleware running on OpenCL.

OpenCL will never be a physics middleware, so comparing the two is really bad and dosn't contribute with anything but ignorance about the topic.

Claim #5
"PhysX is proprietary and thus bad!"

This is really mindboggling.
DirectX is proprietary.
X86 is proprietary.
Hell, even Windows is proprietary.

Most technologies are infact proprietary and companies licenses proprietary technologies from each other all the time.

AMD licenses proprietary technologies from NVIDIA.
NVIDA licenses proprietary technologies AMD.
AMD licenses proprietary technologies from Intel.
Intel licenses proprietary technologies AMD.
The list goes on and on.

Just because something is proprietary dosn't make it bad.
This claim is often made with a foundation in brand loyality and nothing else.

Claim #6
"PhysX is an aesthetic feature, it doesn't do much for gameplay."

This is another mindboggling claim.
One of the first games that features PhysX was CellFactor.
It featured destructable architechture and that is gameplay altering.
Another game featuring this is Warmonger.

The claim is based on ignorance, either due to a lack of expore to such a games.
Or more mindboggling, as the poster who made this claim prefers "scripted physics" over "interactive physics" thus wanting to stall the development due to brand preferences..and his favourite brand dosn't yet have GPu-physics.

Stagnation is the opposite of progress and a really sad stance to have.

*space for further false claims as they are spotted*

Anyone have something they want added to the list, feel free to PM me or post it in this thread.
I think it would be nice to compile a list of the most comon false claims, so people don't have to use time to debunk the same false claims over and over again.
 
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Ancalagon44

Diamond Member
Feb 17, 2010
3,274
202
106
Claim #6
Its worth buying an nVidia card solely for PhysX

It just isnt. I've yet to see a single PhysX game that benefits from it enough for it to be worth it. Developer support is just not happening for PhysX, and it doesnt help that most games these days are developed on console and then ported to PC.

Proprietary being bad is a bigger kettle of fish than just that, look at the Free and Open Software Movement. Its not just about licensing. Regarding licensing though, because this has to do with marketing, AMD will never license PhysX. Just wont happen. Bullet Physics, if its not tied to either of AMD, Intel, or Nvidia, has the best chance of succeeding. Havok, now being Intel owned, will likely not get much work in the GPU support department unless Intel starts another discrete GPU project.
 

Lonbjerg

Diamond Member
Dec 6, 2009
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Claim #6
Its worth buying an nVidia card solely for PhysX

It just isnt. I've yet to see a single PhysX game that benefits from it enough for it to be worth it. Developer support is just not happening for PhysX, and it doesnt help that most games these days are developed on console and then ported to PC.

Proprietary being bad is a bigger kettle of fish than just that, look at the Free and Open Software Movement. Its not just about licensing. Regarding licensing though, because this has to do with marketing, AMD will never license PhysX. Just wont happen. Bullet Physics, if its not tied to either of AMD, Intel, or Nvidia, has the best chance of succeeding. Havok, now being Intel owned, will likely not get much work in the GPU support department unless Intel starts another discrete GPU project.

Your personal stance is irrelevant, we are not talking flavours or preferences here, but factual false claims.

Nice try though.
 

Jacky60

Golden Member
Jan 3, 2010
1,123
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I think the point Ancalagon makes is perfectly valid. A niaive purchaser might think having read the first five claims that the answer is to buy an Nvidia card. This is quite clearly not the case as Ancalagon points out.
 

DaveSimmons

Elite Member
Aug 12, 2001
40,730
670
126
Your rebuttal to Claim 2 is false. Software physics are more limited in the amount of bodies, particles, etc. that can be computed but there is nothing preventing the code from using random number generators or including the current state of a model.

Claim 3 is a strawman since the fact being stated in threads is that an nvidia GPU is needed to run hardware PhysX. It is mentioned as a selling point for nvidia cards, which only makes sense if hardware PhysX is being discussed.

Claim 4 is also changing the argument, because those saying DirectCL / DirectCompute are better mean better than CUDA+PhysX in an openness or licensing sense not in a technical sense.

Your Claim 5 rebuttal is also arguable since DirectX, x86 and Windows are GPU-neutral, the vendors controlling them don't have a reason to favor their GPU over a competitor's.

PhysX is controlled by nvidia, and even if they offered licensing to AMD on reasonable terms nothing currently would stop them from then stabbing AMD in the back with changes that made it run poorly on AMD GPUs compared to nvidia's.
 

Lonyo

Lifer
Aug 10, 2002
21,938
6
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Fine, how about Misleading Claim #1: Lots of games use PhysX.

Yes, many games use PhysX, as you have stated, it runs on almost every platform.
hardly any games at all however use GPU accelerated PhysX, meaning that the PhysX everyone talks about, that supported by GPUs (and thus relevant to this forum) is used by only a very small percentage of all PhysX titles, meaning PhysX in general is only a CPU software.

Since this is the video card and graphics forum, when people say PhysX they usually are talking about the PhysX relating to this forum, which is the one hardly anyone uses, the GPU PhysX.
 

dguy6789

Diamond Member
Dec 9, 2002
8,558
3
76
How many legitimately good games are out that support hardware PhysX? How many games can someone honestly say that hardware PhysX support has helped the game and not hurt it?
 

Lonyo

Lifer
Aug 10, 2002
21,938
6
81
How many legitimately good games are out that support hardware PhysX? How many games can someone honestly say that hardware PhysX support has helped the game and not hurt it?

Well since there are about 12 games which support GPU PhysX, the number of good games supporting it is probably somewhere there or lower.
 

notty22

Diamond Member
Jan 1, 2010
3,375
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Batman: Arkham Asylum -2009
Mafia II -2010
PhysX is very important in both games, and they were major releases.

I'd assume the sequel to Batman which is listed in that Unreal3 engine list , might also feature phsyX
Batman: Arkham City


arkhammp.jpg
 

dguy6789

Diamond Member
Dec 9, 2002
8,558
3
76
Two good games. However, you'd be hard pressed to find a lot of people who think PhysX support was good for Batman. There was also a really big thread on this forum on how disappointed people were in Mafia II's PhysX implementation.
 

SlowSpyder

Lifer
Jan 12, 2005
17,305
1,002
126
I don't think anyone is disagreeing with the potential Physx (or other hardware accelerated physics engines) have. But the use of Physx so far is near worthless to many gamers. CPU physic, even scripted, can be done well enough to be more immersive than hardware physics... just because the physics is done on the GPU, that does not make is superior automatically.

Lonbjerg, you tout Physx so often, it's almost wierd. I don't see anyone here saying Physx doesn't have potential. I see a lot of people here that are like me, I don't care what piece of hardware handles physics (I really couldn't care less if my friggen sound card handled it) if it is well done and immersive.
 

happy medium

Lifer
Jun 8, 2003
14,387
480
126
How many physx haters actually have 2 good Nvidia cards and have tried physx?
Thats what I want to know. It seems most negative comments about physx have no merit from a guy that has or has allways had a AMD card.

I don't think this thread was based on opinions, and should not be rebutted with personal opinions.
 

SlowSpyder

Lifer
Jan 12, 2005
17,305
1,002
126
How many legitimately good games are out that support hardware PhysX? How many games can someone honestly say that hardware PhysX support has helped the game and not hurt it?


I actually was going to post something like this as well. In the past I was able to post a link to Gamespot.com's nominees for game of the year, I can't find it other than in video form now. Not that Gamespot.com has the be all end all say in what is a good game, but it is a popular site that many gamers visit. How many of their game of the year nominees use Physx? If Physx is so incredible, why are their so many games (all of the nominees? I really am not sure) that don't use it but are yet fantastic games?

Again, I am not doubting the potential of Physx (or hardware based physics engines) just that I'm more concerned with playing the game and being sucked into it's world than wondering what piece of hardwar is handling the particle effects I see.
 

DaveSimmons

Elite Member
Aug 12, 2001
40,730
670
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How many physx haters actually have 2 good Nvidia cards and have tried physx?
Thats what I want to know. It seems most negative comments about physx have no merit from a guy that has or has allways had a AMD card.

I don't think this thread was based on opinions, and should not be rebutted with personal opinions.

"PhysX haters"? Most people downplaying the current value of hardware PhysX do so because of the lack of games that show it making a significant difference in the gameplay.

Similar to how the more even-handed of us downplayed the value of DirectX 11 back when it was an AMD exclusive.

Show me the real games, that I actually want to play, where the DirectX 10/11 or hardware physics really matters.

Also, the "claims" being rebutted are not the points being debated in other threads.
 

happy medium

Lifer
Jun 8, 2003
14,387
480
126
Show me the real games, that I actually want to play, where the DirectX 10/11 or hardware physics really matters.
I find it hard to believ out of the millions and millions of mafia 2 and Batman buyers that knowone played it with physx.

personally I have never tried it but I was thinking about buying a used gtx260 for 85$ and giving it a go.
 

badb0y

Diamond Member
Feb 22, 2010
4,015
30
91
I tried PhysX it's nothing special, it's not compelling me to buy nVidia at all. The only thing that is enticing for me to go nVidia is their better support for S3D gaming and since I don't have a 120 Hz monitor that's a non-issue for me right now.

I do however believe that PhysX has the opportunity to be the next big "step" in PC gaming but nVidia has to open up a little. At least they should allow a nVidia to run PhysX on it's own card when the primary card is AMD. Don't tell me that it's not possible or it's not going to function well because I remember those beta drivers that were released a year that worked on AMD systems fine. As far as I can tell nVidia is trying to put a software restriction to prevent nVidia cards from running PhysX when the primary card is AMD.
 

Aristotelian

Golden Member
Jan 30, 2010
1,246
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I find it hard to believ out of the millions and millions of mafia 2 and Batman buyers that knowone played it with physx.

personally I have never tried it but I was thinking about buying a used gtx260 for 85$ and giving it a go.

Playing it with PhysX and "having it be a compelling reason to buy Nvidia hardware" are two very different things. That's the whole 'subjective' thing. I think PhysX is 'okay' at best, (and to be honest, the effects seem very overdone to me in places), and I bought two 580s without giving PhysX a second thought. I don't see it being as big a deal as people make it out to be (yet), but perhaps that'll change in the future.
 

MrK6

Diamond Member
Aug 9, 2004
4,458
4
81
It's great when people state their opinions as fact, it just warms my heart :rolleyes:

Claim #1 - GPU's probably have more horsepower when calculating physics, but how much of that is actually available when you're pushing maximum quality graphics at high resolution with 4x+ AA? Oh, right, very little. However, generally two of my four cores are doing jack when I'm playing a game, so proportionally there can be a lot more horsepower there that is readily available. Unless, of course, this is advocation for buying a "physics only" card is the best solution to get enhanced physics adopted into the mainstream, which we all know how that worked out (i.e. Aegia).

Claim #2 - People talk about BF: BC2 and Ghostbusters because the physics actually changed the gameplay in a meaningful way and catapulted gaming physics forward in a way PhysX couldn't touch despite it's four year+ effort. When my squad and I are huddled on the top floor of a house hiding from a hail of bullet fire when suddenly the wall next to me blows up from an RPG, I'm not counting the bricks to see if it was the same as last time, my butt is already parachuting out the opposite side to escape the inevitable next round. Anyone who's arguing "oh, it's prettier/more realistic" has lost just as much focus as NVIDIA has on actual, meaningful implementation, and this is why PhysX on the GPU is a failure. Another great example is the "interactive steam" in Batman: AA. Great, the steam moves with you at a 50&#37; performance drop. Volumetric steam would look 90% the same with a 5% of the performance penalty, and no one would care as they're trying to chase down and knock out this bad guy.

Claim #5 - Proprietary isn't bad. Proprietary and useless is.

Claim #6 - Ask most people on this forum, never mind an average Joe, if they've heard of Cellfactor and Warmonger, and you'll most likely get a blank stare. Meanwhile, you can go up to any person on the street aged 10-30 and ask them if they've heard of Battlefield: BC2 and you'll get an affirmative. See the difference? To claim that PhysX has done anything for gameplay is just marketing speak or wishful fanboy thinking. If PhysX was worth more than crap, we'd all have NVIDIA GPU's right now. Guess what, we don't, because it's worth crap. All the ridiculous marketing speak, elitist write-ups, fanboy ranting, and flat out hissy fits aren't going to change that.
 

DaveSimmons

Elite Member
Aug 12, 2001
40,730
670
126
Show me the real games, that I actually want to play, where the DirectX 10/11 or hardware physics really matters.
I find it hard to believ out of the millions and millions of mafia 2 and Batman buyers that no one played it with physx.

personally I have never tried it but I was thinking about buying a used gtx260 for 85$ and giving it a go.
That isn't what I said.

Of course some players used hardware PhysX to see the papers fluttering in Batman and whatever it added to Mafia II.

It's subjective whether that matters enough to be worth buying either a second card or a more expensive card (eg. 460 => 560) to run hardware PhysX at the same resolution and settings.

I make enough that I could afford tri-SLI 580s and a fourth for PhysX if there was a game where all that would make it significantly more enjoyable for me to play than with a single GPU and software physics.

I haven't found such a game yet.
 

busydude

Diamond Member
Feb 5, 2010
8,793
5
76
How many physx haters actually have 2 good Nvidia cards and have tried physx? Thats what I want to know.

If PhysX implementation changed the way we play games.. then there would be many gamers here who would move to Nvidia in a heartbeat. Your post is to provoke a negative response. Do millions and millions of people have a GTX 570/480/580 to play Mafia II with Max PhysX at playable frame rates?
 
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badb0y

Diamond Member
Feb 22, 2010
4,015
30
91
it's great when people state their opinions as fact, it just warms my heart :rolleyes:

claim #1 - gpu's probably have more horsepower when calculating physics, but how much of that is actually available when you're pushing maximum quality graphics at high resolution with 4x+ aa? Oh, right, very little. However, generally two of my four cores are doing jack when i'm playing a game, so proportionally there can be a lot more horsepower there that is readily available. Unless, of course, this is advocation for buying a "physics only" card is the best solution to get enhanced physics adopted into the mainstream, which we all know how that worked out (i.e. Aegia).

claim #2 - people talk about bf: Bc2 and ghostbusters because the physics actually changed the gameplay in a meaningful way and catapulted gaming physics forward in a way physx couldn't touch despite it's four year+ effort. When my squad and i are huddled on the top floor of a house hiding from a hail of bullet fire when suddenly the wall next to me blows up from an rpg, i'm not counting the bricks to see if it was the same as last time, my butt is already parachuting out the opposite side to escape the inevitable next round. Anyone who's arguing "oh, it's prettier/more realistic" has lost just as much focus as nvidia has on actual, meaningful implementation, and this is why physx on the gpu is a failure. Another great example is the "interactive steam" in batman: Aa. Great, the steam moves with you at a 50% performance drop. Volumetric steam would look 90% the same with a 5% of the performance penalty, and no one would care as they're trying to chase down and knock out this bad guy.

claim #5 - proprietary isn't bad. Proprietary and useless is.

claim #6 - ask most people on this forum, never mind an average joe, if they've heard of cellfactor and warmonger, and you'll most likely get a blank stare. Meanwhile, you can go up to any person on the street aged 10-30 and ask them if they've heard of battlefield: Bc2 and you'll get an affirmative. See the difference? To claim that physx has done anything for gameplay is just marketing speak or wishful fanboy thinking. If physx was worth more than crap, we'd all have nvidia gpu's right now. Guess what, we don't, because it's worth crap. All the ridiculous marketing speak, elitist write-ups, fanboy ranting, and flat out hissy fits aren't going to change that.
+1

qft.
 

bunnyfubbles

Lifer
Sep 3, 2001
12,248
3
0
Batman: Arkham Asylum -2009
Mafia II -2010
PhysX is very important in both games, and they were major releases.[/B]
except PhysX is NOT very important for either game, its purely an aesthetic enhancement that you'd likely never truly appreciate unless you specifically looked for it. This is exactly how I felt when playing Mirrors Edge or Arkham Asylum on either my GTX470s or 5850. I'll admit I haven't played Mafia II but the videos I have seen of it indicate the same thing - aesthetic improvement only. Not that the game looks particularly enticing to own either way.


How many physx haters actually have 2 good Nvidia cards and have tried physx?
Thats what I want to know. It seems most negative comments about physx have no merit from a guy that has or has allways had a AMD card.

I don't think this thread was based on opinions, and should not be rebutted with personal opinions.
I have SLI GTX470s, I don't hate PhysX, but I have yet to play a game (or at least a good game) where PhysX was a gameplay changer and not completely inconsequential to the overall experience.

The OP mentions two games that might qualify - CellFactor and Warmonger. CellFactor was a lousy game that was only worth it as a PhysX demo playground of what might be possible with the new technology, its rated 50 out of 100 on Metacritic. Warmonger is a game I never heard of until now, and I can't even find any reviews on it with a quick google search. So ultimately neither truly qualify, whats the point if the game itself is terrible and no fun?

I find it hard to believ out of the millions and millions of mafia 2 and Batman buyers that knowone played it with physx.

personally I have never tried it but I was thinking about buying a used gtx260 for 85$ and giving it a go.

If you really have a GTX460 why not try running PhysX on that first? Most PhysX games really aren't that processing intensive to justify investing in a dedicated GPU, IIRC its been established a GT240 is plenty for a dedicated PhysX card.
 
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SirPauly

Diamond Member
Apr 28, 2009
5,187
1
0
I think what some may do is simply go to an ideal extreme: Have to be the best thing since sliced bread! A game changer! Something that will simply blow me away and buy nVidia for PhysX!

How about a feature that simply enhances some titles with some modest game-play advantages and improved fidelity -- some great titles and some not so great?

Is PhysX in its current form an absolute must have? No.

Is it good to see a start of GPU Physics and to get the ball rolling, foundations for tools and to try to bring awareness and some content to boot? Sure!

Many desire to see Physics re-define gaming -- probably believe that Physics has great potential but heck, it has to start first, evolve and mature and simply can't get there without the chaos and growing pains. Would love to see ideal Physics, too.